It’s no exaggeration to say that without Greg Matloff, there would have been no Centauri Dreams. After reading his The Starflight Handbook (Wiley, 1989) and returning to it for years, I began working on my own volume in 2001. Research for that book would reveal Matloff’s numerous contributions in the journals, especially on solar sail technologies, where he illustrated early on the methods and materials needed for interstellar applications. A professor of physics at New York City College of Technology (CUNY) as well as Hayden Associate at the American Museum of Natural History, Dr. Matloff is the author of, among others, Deep Space Probes (Springer, 2005) and Solar Sails: A Novel Approach to Interplanetary Travel (with Les Johnson and Giovanni Vulpetti; Copernicus, 2008). His latest, Starlight, Starbright, is now available from Curtis Press, treating the controversial subject of today’s essay.
by Greg Matloff
Introduction: Motivations
As any web search will reveal, most of my research contributions have been in the fields of in-space propulsion, SETI, Earth-protection from asteroid impacts, planetary atmospheres, extra-solar planet detection and spacecraft navigation. Since I have consulted for NASA on solar-sail applications, I have trained myself to err on the side of conservatism. However, a true scientist cannot ignore observational data. He or she must base hypothesis and theories upon such results, not upon previous experience, ideology and dogma.
Image: Gregory Matloff (left) being inducted into the International Academy of Astronautics by JPL’s Ed Stone.
Until 2011, I never expected that I might contribute to the fascinating debate regarding the origin and nature of consciousness. On one side are the epiphenomenonalists, who believe that consciousness is a mere byproduct of bio-chemical activity in the complex brains of higher organisms. On the other side are the panpsychists, who believe that a universal field responsible for consciousness, sometimes referred to as “proto-consciousness,” reacts with matter to produce conscious activity at all levels. The philosophical arguments were fascinating, but to me as a scientist they were a bit disappointing. There seemed to be no way of elevating the argument from the realm of deductive philosophy to the realm of observational/experimental science.
But in 2011, as documented in my June 12, 2012 contribution to this blog – Star Consciousness: An Alternative to Dark Matter – I learned (much to my surprise) that it may be possible now to construct simple models of universal consciousness and test them against observational evidence.
I was primed for this work by several factors. First, an early mentor of mine and a coauthor of several astronautics papers, was the late Evan Harris Walker. With expertise in plasma and quantum physics, Harris (as his friends called him) was a pioneer in the infant field of quantum consciousness. Although I am far from an expert in quantum mechanics, I was fascinated by Harris’ attempt to explain consciousness by the quantum tunneling of wave functions through potential wells created by the inter-synaptic spacing in mammal brains [1].
After the success of The Starflight Handbook and other contributions to interstellar travel studies, I was asked by Apollo 11 astronaut Buzz Aldrin in the early 1990’s to join the team of scientific consultants for a science-fiction novel he was co-authoring with John Barnes [2]. For plot purposes, Buzz required the stable, long-term existence of a Jupiter-like planet at a 1 Astronomical Unit (AU) distance from a Sun-like star. When he asked me to check the possibility of such a planet, I was initially very pessimistic. When I told Buzz that most exoplanet experts believed that the Hydrogen-Helium atmosphere of such a planet would likely evaporate quickly (in cosmic terms), he asked me to check this assumption. I located an appropriate equation in a space science handbook and calculated the estimated lifetime of the giant planet’s atmosphere. I was surprised and Buzz was gratified to learn that the lifetime of the Jovian’s atmosphere at 1 AU would be billions of years. At that point in my career, I was an adjunct professor and consultant. Since I was unable to locate a derivation for the subject equation, I elected not to challenge scientific orthodoxy and attempt to publish these results in a scientific journal. After the discovery of “hot Jupiters” circling Sunlike stars a few years later, I became credited (by Paul Gilster and others) with predicting the existence of hot Jupiters in a science-fiction novel, but not in a peer-reviewed journal. I vowed to never repeat this mistake again and hold back data, if my results challenged established paradigms.
The third influence pointing me in the direction of conscious stars was an undergraduate, liberal arts student at New York City College of Technology. Between the time I became a tenure-track professor in 2003 and my retirement from full-time teaching in 2011, I organized and coordinated the astronomy program at New York City College of Technology (NYCCT). In the first term of the NYCCT astronomy sequence, students learn about astronomical history, aspects of classical and modern physics and solar-system astronomy. In the second term, they investigate the astrophysics of the Sun, stars, and galaxies, cosmology, and the prospects for extraterrestrial life. In one Astronomy 2 section, I was lecturing about dark matter. The existence of this mysterious substance has been invited to explain anomalous stellar motions. When a liberal arts undergraduate interrupted the lecture, I learned that he doubted dark matter’s existence. His supposition was that physics is at an analogous stage to the situation in 1900. A major shift in physical paradigms may be necessary to explain the many anomalies (including dark matter) building up in observational astrophysics.
In 2011, it all came together. Kelvin Long, who edits the Journal of the British Interplanetary Society (JBIS), invited me to participate in a one-day symposium at the London headquarters of the BIS to celebrate the work of Olaf Stapledon, a British science-fiction author and philosopher who has greatly influenced astronomical and astronautical thought. In his 1937 masterwork Star Maker, Stapledon predicted nuclear energy, nuclear war, interstellar travel, space habitats and rearrangement of solar systems by intelligent extraterrestrials. Because I usually author papers on these topics and have often cited Star Maker, I elected to avoid astrotechnology in my contribution to this BIS symposium and instead concentrate on a core aspect of Stapledon’s philosophy: that the stars and indeed the entire universe are in some sense conscious.
A Toy Model of Stellar Consciousness and Astrophysical Evidence
Many people have written about consciousness. Since there is no agreed upon definition of this quality, I decided to investigate a symptom of stellar consciousness. This is Stapleton’s supposition that a fraction of stellar motions around the centers of their galaxies is volitional. According to Stapledon, stars obey the canons of a cosmic dance as they travel through space. Many researchers consider the seat of consciousness in humans and other lifeforms to be neurons or tubules [1,3,4]. I have little knowledge regarding the intimate details of the stellar interior. But I am pretty sure that neurons and tubules do not exist within stars. However, most cooler stars, including the Sun, do have simple molecules in their upper layers.
Contrary to what many of us learned in high school chemistry, the Van der Waals forces that hold the atoms in molecules together are not purely electromagnetic. Some of this attraction is due to the so-called Casimir Effect [5]. Vacuum is not truly empty. Instead, in tiny intervals of space and time, there are enormous fluctuations of energy and matter. Generally, positive and negative energies in these fluctuations exactly balance. But in the opinion of most cosmologists, the Big Bang was a stabilized vacuum fluctuation. All the matter, energy, space and time in the universe inflated from a tiny volume of dynamic vacuum during this event.
An echo of this most creative event in the universe’s history occurs in every molecule. Not all vacuum fluctuations can fit between adjacent molecules. A fraction of the Van der Waals force holding molecules together is produced by the pressure of these vacuum fluctuations.
With astrophysicist Bernard Haisch [6], I assumed that a proto-consciousness field operates through vacuum fluctuations or is identical to these fluctuations. I developed a very simple “toy model” in which this field produces a form of primitive consciousness by its interaction with molecular matter in the Casimir Effect (Fig. 1).
Fig. 1. A “Toy Model” of Proto-Panpsychism.
But models, no matter how simple or complex, are useful in physics only if they can be validated through experiment or observation. So I conducted a Google search for “Star Kinematics Anomaly and Discontinuity”.
Contrary to my expectation, what appeared on my screen was amazing. There was a Soviet-era Russian astronomer named Pavel Parenago (1906-1960). In addition to his astronomical contributions, Dr. Parenago was a very clever man. Unlike many of his colleagues, he avoided an extended vacation in a very cold place by dedicating a monograph to the most highly evolved human of all times – Joseph Stalin!
The anomaly named after Parenago, which is referred to as “Parenago’s Discontinuity”—is his observation that cool, low-mass stars in our galactic vicinity (such as the Sun) move around the center of the Milky Way galaxy a bit faster than their hotter, higher-mass sisters.
I used two sources to quantify Parenago’s Discontinuity for nearby main sequence stars. One was a chapter in Allen’s Astrophysical Quantities, a standard reference in astrophysics [7]. The second was a compilation of observations of 5610 main sequence stars using the European Space Agency (ESA) Hipparcos space observatory out to a distance of ~260 light years [8]. Figure 2, a graph presenting this data, is also included in my June 12, 2012 contribution to this blog and the JBIS paper based on my contribution to the BIS Stapledon symposium [9].
In Fig. 2, star motion in the direction of galactic rotation is plotted against star (B-V) color index, which is a measure of the difference between star radiant output in the blue range of the spectrum and the center of the human eye’s visual sensitivity. Hot, blue, massive stars have low and negative (B-V) color indices. From Table 19.1 of Ref. 7, G spectral class main sequence stars such as the Sun have (B-V) color indices in the range of about 0.6-0.7.
Fig 2: Solar Motion in Direction of Galactic Rotation (V) for Main Sequence Stars vs. Star Color Index (B-V). Diamond Data Points are from Gilmore & Zelik. Square. Data Points are from Binney et al.
Note in Fig. 2 that cooler stars to the right of the discontinuity move as much as ~20 kilometers per second faster than their hotter sisters around the center of the galaxy. As discussed in the June 12, 2012 contribution to this blog and in Ref. 9, Parenago’s Discontinuity occurs near the point where stable molecules begin to appear in stellar spectra.
Recent Work and Consideration of Alternative Hypotheses
Science is essentially a testing ground of alternative hypotheses to explain observational and experimental data. Since data points to at least the local reality of Parenago’s Discontinuity, some astrophysicists have developed rival explanations to Volitional Stars.
One possibility is stellar boil-off from local stellar nurseries. Perhaps this results in faster motions for cooler, low mass stars. But this process should result in a greater velocity dispersion in low mass stars, not a higher velocity of revolution around the galaxy’s center. Also, stellar nurseries typically live for tens of millions of years [10]. Why is there no discontinuity in the motions of short-lived O and B stars?
If Parenago’s Discontinuity is a local phenomena extending out a few hundred light years from the Sun, at least one other alternative explanation is possible. This is the Spiral Arms Density Waves concept [11]. The matter density of the interstellar medium is not uniform. Although the typical density of ions and neutral atoms in the Sun’s vicinity (the so-called Intercloud Medium) is less than 0.1 per cubic centimeter, matter density in the cooler, mostly neutral diffuse nebula that operate as stellar nurseries in the spiral arms of our galaxy is orders of magnitude greater. If a dense diffuse nebula passed through our galactic vicinity in the distant past, low-mass, cool, redder stars might be dragged along faster by the dense cloud than hot, blue, more massive stars.
There are at least two ways to check the validity of the Spiral Arms Density Waves hypothesis. One is to investigate the typical size of diffuse nebula in the Milky Way galaxy. The second is to check observational consequences of this hypothesis.
In a recent book, I reviewed the sizes of diffuse nebula in Messier’s compilation [12]. As part of a recent research paper, I performed a similar review of the more comprehensive Herschel catalog and an on-line listing of New General Catalog (NGC) deep-sky objects [13]. These results are summarized in Fig. 3.
Fig 3: Fraction of Galactic Bright Diffuse Nebulae with Diameters > D Light Years from Messier (Blue), Herschel (Green) and Atlas of the Universe—NGC (Yellow) Compilations.
Note in Fig. 3 that, in all three compilations of deep-sky objects, diffuse nebulae with diameters greater than a few hundred light years are rare. Since the Hipparcos main sequence dataset used in Ref. 8 includes stars in a ~500 light year diameter sphere, Fig. 3 does not support the Spiral Arms Density Wave hypothesis.
But there is worse news for this hypothesis, also derived from Hipparcos data. Giant stars are considerably brighter than their less evolved counterparts on the main sequence and
are consequently visible over greater distances. Richard Branham, an astrophysicist based in Argentina, has analyzed the kinematics of thousands of giant stars in the Hipparcos data set [14]. His conclusion that Parenago’s Discontinuity is present in these results is demonstrated in Fig. 4.
Fig 4: Giant Star Motion (V) in Direction of Sun’s Galactic Revolution. The reduction of Branham’s data to produce Fig. 4 is discussed in Chap. 23 of Ref. 12.
Note that Fig. 4 is not as neat as the corresponding results for main sequence stars in Fig. 2. This may be due to uncertainty in the > 1,000 light year distance estimates for many of the stars in Branham’s Sample.
An interpretation of the above results is that a local explanation for Parenago’s Discontinuity is unlikely. Existing galactic diffuse nebula are simply too small (and widely separated, as discussed in Ref. 12) to produce a stellar kinematics anomaly over a radius greater than 1,000 light years.
However, although the existing data does not support Spiral Arms Density Waves, the sample of stars, which numbers in the thousands, is not large enough to rule out this and other local explanations for Parenago’s Discontinuity. After all, the Milky Way galaxy contains more than a hundred billion stars.
Within the next few years, astrophysicists should know conclusively whether Parenago’s Discontinuity is a local or galactic phenomenon. In December 2013, the European Space Agency (ESA) launched Gaia as a more capable successor to the Hipparcos space observatory. While Hippasrcos accurately determined the distance and motions of perhaps 100,000 stars,
Gaia should gather similar data over the next few years for about a billion stars in the Milky Way galaxy. Gaia, its mission and capabilities are discussed in more detail in Ref. 12.
Fig 5: The European Space Agency’s Gaia Space Observatory (Courtesy ESA).
But even before the data from Gaia is analyzed and released, astronomers using different equipment have gathered preliminary data that may lead to the falsification of the Spiral Arms Density Waves hypothesis. Note in Fig. 6 the structure of M51, a typical nearby spiral galaxy not dissimilar from the Milky Way. The revolution of this galaxy is in the counterclockwise direction, from our point of view. Hundreds of millions of years are required for one
complete revolution [15].
A team of astronomers have carefully analyzed the light received from the leading and lagging edges of spiral arms of twelve nearby spiral galaxies. For the Spiral Arms Density Waves Hypothesis to be correct, differences should be observable between these two locations. Sadly for Density Waves (and happily for Volitional Stars), such an effect was not noticed.
Fig 6: The Whirlpool Galaxy M51 (courtesy NASA).
Since the universe contains ~100 billion spiral galaxies, this result is not conclusive. Using new telescopes, about 300 spirals should be observed to statistically rule out Density Waves. Density Waves is apparently limping, but it cannot yet be completely ruled out.
If observations from Gaia indicate that Parenago’s Discontinuity is a galactic phenomenon rather than a local phenomenon, some astrophysicists will attempt to develop explanations that are alternatives to Volitional Stars. As discussed in Ref. 13, this will be challenging. The only reasonable galaxy-wide explanation might be a collision between the Milky Way galaxy and another large galaxy in the distant past. While such a collision might have produced a galaxy-wide “starburst” episode of rapid star formation, simulations indicate that the ultimate result of such galaxy smash-ups is a giant elliptical galaxy, not a spiral such as the Milky Way.
Volitional Star Kinematics
In my June 12, 2012 contribution to this blog, I considered methods that a volitional star could use to adjust its galactic velocity. One possibility was stellar jets.
Many infant stars eject high-velocity matter streams (Fig. 7). Surprisingly, some of them are unipolar or unidirectional, ejecting more material in one direction than others [16]. In April 2015, Paul Gilster e-mailed a link indicating that solar winds from mature stars like the Sun
enter interstellar space in a complex system of jets [17]. The complexity of these jets is at least partially due to solar galactic motion and the interaction between the solar and galactic magnetic fields. Uni-directional matter jets from infant and young stars are discussed in greater detail in Chap. 15 of Ref. 12.
Fig 7: A Jet of High-Velocity Material Ejected From an Infant Star (courtesy NASA).
If Gaia observations reveal that Parenago’s Discontinuity is a galaxy-wide phenomenon, attention might turn to these unidirectional stellar jets. Are they generally aligned to accelerate molecule-bearing stars in the direction of their galactic motion? Since star galactic revolution velocities generally increase with distance from the galactic center, do jet velocities increase as well?
Although unidirectional material jets from infant and mature stars is one method that a volitional star could use, there is another possibility. This is the admittedly very controversial possibility of a weak psychokinetic (PK) force. Much has been written about the investigation of PK and related paranormal phenomena funded by US intelligence agencies.
As I have described in my earlier treatments of this subject, this is the only scientific controversy that I am privileged to know participants on opposing sides. On one hand are the physicists who claim that Uri Geller, the alleged psychic who scored best on their screening tests, could not possibly have cheated on these tests. On the other hand, I met a retired Time-Warner editor at a cocktail party years ago who demonstrated that Geller’s signature fork bending could be duplicated as a magic trick, and who also claimed to have enlisted a magician The Amazing Randi, to further investigate Geller.
Many web sources conclude that Geller is indeed a trained magician. When my friend Dr. Eric Davis of the Institute for Advanced Studies at Austin (Texas) mentioned (while reviewing a draft copy of Ref. 12) that there is no confirmation of Geller actually having attended a magician’s college, I decided to check what I consider the best reference available on the Geller-Randi controversy. I carefully checked a book by MIT physics professor David Kaiser on this topic and learned that Dr. Davis is apparently correct [18].
Eric Davis also sent me an electronic copy of a report he authored for the US Air Force in 2005. Many countries other than the US have investigated PK and related phenomena in studies funded by government agencies. Some of the results are positive and have reportedly been replicated [19, 20].
As discussed in Refs. 9 and 12 and my June 12, 2012 submission to this blog, a PK force required to accelerate a Sun-like star by 20 km/s during a ~1-billion-year time interval is many orders of magnitude less than that required to bend a kitchen utensil. Perhaps it is time for experimental physicists to put the Geller-Randi controversy aside and perform a new set of carefully controlled experiments to test the existence or non-existence of a weak PK effect.
One possibility discussed by others is to include professional magicians on the experiment design team. Another possibility, raised by a responder to my June 12, 2012 contribution to this blog, is to perform PK tests on the interaction between human subjects and an Einstein-Bose condensate. As further discussed in Ref. 12, an Einstein-Bose condensate is a macroscopic state of matter in which all of the particles share the same quantum state. A human subject might be instructed to see if he or she could “will” the condensate to climb the enclosure wall repeatedly to the same level. This would test not only the validity of PK but the assumption that consciousness is related to quantum phenomena.
Conclusions: A Learning Experience
Since 2011, I have spent a large fraction of my creative time investigating whether the Volitional Star hypothesis can be considered scientific. As reviewed in Ref. 12, it is certainly a venerable concept. Shamans, astrologers, philosophers, mystery-cult members, poets, and fiction authors have considered this possibility for millennia.
It is also interesting that at least a few scientists have walked this path before me. Although the concepts of stellar or universal consciousness are certainly not in the scientific mainstream at present, scientific speculation along these lines is becoming more respectable.
One creative group that apparently welcomes these concepts is fine artists. The chapter frontispiece art in Ref. 12 created by C Bangs has been presented in several artistic forums, including the Arts Program at the 9th IAA Symposium on the Future of Space Exploration, which was held in Turin, Italy in July 2015. A version of one of these images is presented as Fig. 8. Modifications of 18 of these images on 11″ X 14″ panels painted on both sides in the form of an accordion book are on display at the Manhattan gallery that C Bangs is affiliated with: Central Booking Art Space, 21 Ludlow Street.
Fig 8: Modified Version of C Bangs Chapter frontispiece from Starlight, Starbright.
Recently, with my assistance, C prepared an Artist’s Book entitled Star Bright?. In July 2015, Star Bright? was collected by the Prints and Illustrated Books division of the Museum of Modern Art in Manhattan.
It is of course very premature to claim that the work presented here has proven the case for volitional stars. The toy model of proto-panpsychism is certainly too simple to have much traction in the theoretical world. But it is not impossible that this work might move panpsychism from the realm of deductive philosophy to the realm of observational astrophysics.
References
1. E. H. Walker, “The Nature of Consciousness,” Mathematical Biosciences, 7, 131-178 (1970). Also see E. H. Walker, The Physics of Consciousness, Perseus, Cambridge, MA (2000).
3. L. Margulis, “The Conscious Cell”, Annals of the New York Academy of Sciences, 929, 55-70 (2001).
4. S. Hameroff, “Consciousness, the Brain, and Spacetime Geometry”, Annals of the New York Academy of Sciences, 929, 74-104 (2001) and R. Penrose, “Consciousness, the Brain, and Spacetime Geometry: An Addendum”, Annals of the New York Academy of Sciences, 929, 105-110 (2001).
6. B. Haisch, The God Theory, Weiser, San Francisco, CA (2006).
7. G. F. Gilmore and M. Zelik, “Star Populations and the Solar Neighborhood,” in Allen’s Astrophysical Quantities, 4th ed. A. N. Cox ed., Springer-Verlag, NY (2000), Chap. 19.
8. J. J. Binney, W. Dehnen, N. Houk, C. A. Murray, and M. J. Preston, “Kinematics of Main Sequence Stars from Hipparcos Data,” Proceedings of the ESA Symposium Hipparcos Venice
’97, SP-402, Venice, Italy, 13-15 May 1997, pp. 473-477 (July, 1997).
9. G. L. Matloff, “Olaf Stapledon and Conscious Stars: Philosophy or Science?”, JBIS, 65, 5-6 (2012).
10. E. Chaisson and S. McMillan, Astronomy Today, 6th ed., Pearson-Addison/Wesley, San Francisco, CA (2008), Chap. 19.
11. R. S. DeSimone, X. Wu, and S. Tremaine, “The Stellar Velocity Distribution of the Stellar Neighborhood”, Monthly Notices of the Royal Astronomical Society, 350, 627-643 (2004).
13. G. L. Matloff, “The Non-Locality of Parenago’s Discontinuity and Universal Self Organization”, IAA-FSE-15-06-03. Presented at 9th IAA Symposium on the Future of Space Exploration, Turin, Italy, July 7-9, 2015. Published in Conference Proceedings.
14. R. L. Branham, “The Kinematics and Velocity Ellipsoid of GIII Stars,” Revisita Mexicana de Astronomia y Astrofisica, 47, 197-209 (2011).
15. K. Foyle, H.-W. Rix, C. Dobbs, A. Leroy, and F. Walter, “Observational Evidence Against Long-Lived Spiral Arms in Galaxies,” Astrophysical Journal, 735 (2), Article ID = 101 (2011), arXiv: 1105.5141 [astro-ph.CO].
16. F. Namouni, “On the Flaring of Jet-Sustaining Accretion Disks”, Astrophysical Journal, 659, 1505-1510 (2007).
17. I. O’Neill, “Sun May Blast Two Jets of Plasma into Interstellar Space”, news.discovery.com, (March 4, 2015). Also see “A New View of the Solar System: Astrophysical Jets Driven by the Sun”, bu.edu (February 19, 2015).
18. D. Kaiser, How the Hippies Saved Physics, Norton, NY (2011).
19. E. W. Davis, “Teleportation: Mind and Intelligence”, Report to the US Air Force Future Technology Branch, Future Concepts and Transformation Division Workshop, Mitre Corporation, McLean VA (Oct. 21, 2005).
20. E. W. Davis, “Teleportation Physics Study,” Final Report AFRL-PR-ED-TR-2003-0034, Air Force Research Laboratory, Air Force Materiel Command, Edwards AFB, CA (2004): https://www.fas.org/sgp/eprint/teleport.pdf
His interest fired by an interview with interstellar researcher Greg Matloff, Dale Tarnowieski became fascinated with the human future in deep space. One result is the piece that follows, an essay that feeds directly into a recent wish of mine. I had been struck by how many people coming to Centauri Dreams are doing so for the first time, and thinking that I would like to run the occasional overview article placing the things we discuss here in a broader context. Dale’s essay does precisely this, looking at our future as a species on time frames that extend to the death of our planet. Dale retired in January 2015 from the position of assistant director of communications with New York City College of Technology/CUNY, a veteran journalist and editor of “Connections,” the college’s print and online magazine. He also did considerable writing for the New York City College of Technology Foundation and its annual Best of New York Award Dinner (and continues to do so on a freelance basis). Here he reminds us of the Sun’s fate and asks how — if we and our planet get through our technological infancy — we will find ways to move into the Solar System and, eventually, out into the Orion Arm.
By Dale Tarnowieski
Mother Earth – our home, sweet home – won’t be our home forever. In one billion years, give or take, increased heat from a steadily warming Sun will cause our planet’s temperatures to double, its oceans to boil away, and its land surfaces to turn to sand or melt. Assuming we’re still around, we’ll have to relocate before that happens.
A billion years is a long time off, so why the hurry to establish a foothold in space? One answer comes from astrophysicist Stephen Hawking, who warns that we may have as few as 200 years to establish permanent settlements on other worlds and begin mining our solar system for its bounty. Our numbers and the depletion of our planet’s finite resources are growing exponentially, as is our ability to alter the biosphere for good and ill. Within two centuries, Hawking contends, we could exhaust the resources available on Earth essential to our survival and damage our environment beyond repair.
But assuming we successfully respond to these more immediate challenges, the longer-term threat to our survival posed by a progressively warming Sun is one we won’t be able to avoid. We are already contemplating the use of mirrors in space to deflect sunlight as an anti-global warming measure as well as devices called space sunshades at neutral-gravity positions in the Earth-Sun system to reduce the increasing heat from our parent star. But such devices will do nothing to protect us when that heat becomes so intense that our only option will be to abandon our planet.
Now middle-aged, the Sun’s luminosity has increased 30 percent since its birth 4.6 billion years ago and will increase another 10 percent over the next one billion years. The radius of a more luminous Sun is projected to expand an estimated 200 times within four-to-five billion years and Mercury, Venus and possibly Earth and Mars will be vaporized.
Numerous natural or man-made catastrophes could bring most or all life on Earth to an end before the excessive heat from a warming Sun compels humankind’s relocation. But assuming no such catastrophe occurs, that move is only the first of two we’ll have to make. Several billion years later, it will be necessary to leave the solar system altogether as our dying Sun begins to swell.
Image: A charred and glowing Earth of the far future, the Sun having long since entered its red giant phase. Credit: Wikimedia Commons CC BY-SA 3.0.
Holding Off the Inevitable
Could the abandonment of our world be avoided? In 2001, researchers Don Korycansky of the University of California-Santa Cruz, Gregory Laughlin of NASA and Fred Adams of the University of Michigan suggested that by maneuvering an asteroid 100 kilometers wide approximately 16,000 kilometers above Earth’s surface once every 6,000 years, we could slowly nudge our planet away from a more luminous Sun. But a collision with an object of such size would only have to happen once to prove catastrophic.
When our time on Earth runs out, the fortunate among us will join those already dwelling aboard orbital settlements circling more distant planets or their moons. Current thinking envisions others relocating to huge mobile in-space habitats called world ships or to open-air or enclosed settlements on Mars – the open-air variety depending on our successfully terraforming, or environmentally modifying, the biosphere of what at present is a frozen desert of a planet.
None of the other planets in our solar system is now remotely habitable. Closer to the Sun, a nearly atmosphere-free Mercury’s temperatures vary between -173 Celsius at night to +427 Celsius during the day. The latter is hot enough to melt lead. Venus is even hotter and possesses one of the deadliest atmospheres in the solar system. Farther from the Sun than Earth, Mars’s thin atmosphere is composed mostly of carbon dioxide and the planet’s weak gravity poses problems with respect to the retention of atmospheric gases. The four even more distant giants – Jupiter, Saturn, Uranus and Neptune – all have relatively small, dense cores surrounded by massive layers of gas. Jupiter and Saturn have thick atmospheres consisting primarily of hydrogen and helium, while Uranus is a world of liquid ice and Neptune home to wind speeds ten times those of the strongest hurricanes on Earth.
There are proposals for colonizing all of these worlds, including one that calls for the construction of an artificial surface together with its own life-supporting biosphere above the existing atmosphere of Jupiter. But among these proposals, the terraforming of Mars seems the most feasible based on current and anticipated technology.
Formation and Destiny of the Solar System
All stars are born and die, and our Sun is an ordinary yellow dwarf star born in a molecular cloud of dust and gas called a nebula. Consisting largely of hydrogen, the denser parts of that nebula underwent gravitational collapse and compressed to form a globule, or spinning ball of extremely hot gas, that later began to cool as a result of its emission of radiation.
As collapse progressed and the globule’s hydrogen atoms drew closer together, the temperature and pressure within that massive ball increased tremendously as did its rate of rotation. This increase in rotational speed also increased the resulting centrifugal force, causing the ball to form a pancake-shaped disk of stellar debris that extended far into space. This debris eventually coalesced through accretion into the four inner rocky and four outer gas or ice planets and other objects to which our solar system is home.
The four inner planets – Mercury, Venus, Earth and Mars – are called terrestrial worlds, which are smaller solid bodies made up of rock and metals with atmospheres of varying densities that were greatly modified early on by sunlight and the solar wind. The reason the four outer gas or ice giants are so much larger is that their greater distances from the Sun preserved, in part, their thick primeval atmospheres that condensed from the solar nebula.
When during the Sun’s formation the temperature of its core reached 15 million degrees Celsius, a process called nuclear fusion began, one sparked by the collision and binding of the core’s hydrogen atoms and their conversion by means of the intense heat produced into helium atoms, the second simplest and lightest of all the elements. This conversion created powerful outward forces of radiation pressure that eventually counteracted the force of inward gravitational collapse.
But as the Sun ages, the time will come when nuclear fusion will temporarily cease as our parent star begins to exhaust its supply of hydrogen and its helium content builds. This temporary cessation of nuclear fusion will briefly eliminate the resulting outward pressure and the Sun’s outer layers will fall inward on its core. This collapse will greatly increase the pressure on the core as well as its temperature, re-igniting the fusion of the Sun’s remaining hydrogen and triggering the fusion of its sizable accumulation of helium. The burning of helium will produce large amounts of carbon, which will act as a catalyst to increase 1,000-fold the rate of the fusion of the Sun’s remaining supply of hydrogen.
The greatly increased temperatures produced by this more intense fusion process will generate even more forceful outward pressure and the Sun will begin to swell enormously by pushing its outer layers deep into space. The movement of these layers away from the core will result in their gradual cooling. Less hot, they will appear less yellow and take on a reddish color as the Sun transforms into a red giant. Our parent star will grow increasingly unstable and release huge and violent bursts of solar material and heat. Because of its corresponding reduction in mass, the Sun’s gravitational sway will weaken and the orbits of the outer planets and other bodies spared incineration will change.
After eventually exhausting its nuclear fuel, the Sun will transform into a white dwarf star about the size of Earth. And theory has it that a very long time after that the Sun will become a cold and invisible dead star called a black dwarf. But the time required for a white dwarf to reach this stage is calculated to be longer than the current age of the universe and no black dwarf is believed to yet exist.
Image: This image tracks the life of a Sun-like star, from its birth on the left side of the frame to its evolution into a red giant star on the right. On the left the star is seen as a protostar, embedded within a dusty disc of material as it forms. It later becomes a star like our Sun. After spending the majority of its life in this stage, the star’s core begins to gradually heat up, the star expands and becomes redder until it transforms into a red giant. Following this stage, the star will push its outer layers into the surrounding space to form an object known as a planetary nebula, while the core of the star itself will cool into a small, dense remnant called a white dwarf star. The protostar stage, on the far left of this image, can be some 2000 times larger than our Sun. The red giant stage, on the far right of this image, can be some 100 times larger than the Sun. Credit: European Space Agency.
Humanity in the Far Future
Life has existed on Earth for 3.8 billion years, with the earliest examples of the human species thought by most anthropologists to have evolved in Africa about 300,000 years ago and anatomically modern examples 200,000 years later. The earliest fossil evidence of the precursors of the human species dates to between 1.9 and 2.4 million years ago.
Assuming our survival over the next one billion years, natural evolutionary processes will allow us to adapt for a while to changing environmental conditions as the Sun becomes more luminous. For example, skin color in humans might become uniformly dark. But we will experience increasing sensitivity to pressure changes as conditions worsen and horrific storms of enormous magnitude become routine and the time will come when we are unable to adapt further.
As conditions on Earth deteriorate, we may continue to dwell above ground in highly protective structures located away from our planet’s equatorial and temperate regions. Such enclaves will have their own energy-generating facilities and water and oxygen will have to be recycled.
But eventually, nearly all humans still living on Earth are likely to take refuge underground. In time, sub-surface or off-planet production of natural or synthetic foods will provide for all of humankind’s nutritional needs. And long before then, we will have moved to the full recycling of virtually all materials employed in the production of goods. Ground and air travel will be severely limited until such means of transportation become extremely problematic, and space elevators, rather than rocket-propelled vehicles, will transport people and materials to and from Earth orbit.
Toward Other Stars
The future exploration and settlement of nearby space beyond the Earth-Moon system will require many technological advances and innovations, including the use of solar system resources for propulsion systems that do not employ chemical propellants. For manned flights beyond the Moon, a generic in-space habitat module will need to be perfected. Shielding will need to be developed to reduce crew exposure to galactic cosmic rays and solar flares and solar flare warning time will need to be increased. Some type of landing vehicle, surface habitat and an enhanced space food system will have to be developed for missions to Mars and beyond.
Also required will be the development of technologies that enable us to explore the near-interstellar environment. First, advanced robotic probes will visit the heliopause at about 200 Astronomical Units or AUs, where one AU is the mean distance between Earth and the Sun. Later missions will explore the Sun’s inner gravitational focus at 550 AUs and finally the inner reaches of the Sun’s Oort Cloud at 1,000 AUs.
Much later, faster and even more advanced robotic probes will fly through neighboring star systems with potentially habitable planets. These will be followed by probes that will decelerate in selected planetary systems and dispatch landing craft to the surfaces of suitable planets in the habitable zones of targeted stars. Full computer management of these missions will be necessary, because even speed-of-light communications over such vast stretches of space will preclude real-time oversight by humans located in our solar system.
While nearly all of today’s rockets are fueled by chemical propellants, future spacecraft operating within our solar system are likely to be propelled by either the Sun or nuclear fission or fusion, which would greatly reduce travel times to Mars and beyond. Current thinking calls for spacecraft venturing beyond our solar system to be propelled by some type of fusion reaction or a light sail, although an antimatter propulsion system and electric sailing on the solar wind are other possibilities. Moreover, new systems of deceleration at journey’s end will need to be developed.
Image: About as futuristic as it gets, this is a design visualization of a black hole augmented interstellar ramjet concept developed by Kelvin Long for the Initiative for Interstellar Studies. Credit: Adrian Mann.
The two principal dangers to humans in the manned exploration of space are cosmic rays and microgravity. Too large a flux of cosmic rays can result in cancer or mental degradation. Long-term exposure to microgravity can cause muscle and bone deterioration.
If a craft is moving rapidly, the induced cosmic ray flux caused by impacting interstellar ions and atoms could be alleviated by thick shields in front of the habitat section. A combination of thick shields and magnetic fields around the habitat would greatly reduce the flux of galactic cosmic rays. Microgravity effects could be reduced by spinning a ship in order to produce fractional Earth gravity on the inner rim.
If a craft is moving at a higher fraction of the speed of light, one problem is occasional impacts by cosmic dust particles. A shield in front of the craft or a combination of particle-detecting radar and particle-zapping lasers could alleviate this problem. If the ship must make a close solar pass, special care must be taken to protect crew and equipment from high-energy solar photons and solar winds.
Even close to home, spacecraft might be impacted by cosmic rays produced by a distant exploding star, or supernova. To protect the crew, a shield could be attached to the habitat to block the cosmic ray flux from the supernova. Since gamma rays are neutrally charged high-energy electromagnetic photons, mass shielding rather than magnetic fields would be necessary.
The dangers inherent in cosmic rays might be alleviated on manned trips to Mars through a method of travel described in a March-April 2011 Acta Astronautica article, “NEOs as stepping stones to Mars and main-belt asteroids,” by Gregory Matloff and Monika Wilga. This method makes use of space resources located not far from Earth – those small asteroids or comets known as “Near-Earth Objects” or NEOs. The article calls this form of travel “NEO hitchhiking.”
Most of those celestial icebergs we call comets reside in two locations far from the Sun in the distant Kuiper Belt and Oort Cloud, while most of the rocky and stony minor planets or asteroids are located in the Asteroid Belt between Mars and Jupiter. In recent decades, however, increasing numbers of extinct comet and asteroid-like objects have been observed in orbits that bring them close to Earth.
Following Earth escape, a velocity change would be applied to a human-piloted spacecraft bound for Mars, a change that allowed the craft to rendezvous with a NEO two to three months later. During the balance of the interplanetary flight and after the crew imbedded the craft within the NEO, the latter’s material would be used to shield the craft from cosmic rays.
While during any ship’s return voyage a similar strategy would be followed, various mission proposals suggest that diverse contingents of space travelers sent to Mars, for example, should expect to stay and never to return to Earth. Such one-way missions could be accomplished with less difficulty and at less cost. Their crews would establish settlements that would expand as additional travelers followed and those already there reproduced.
Terraforming a Close Neighbor
The terraforming and colonization of Mars – the only other planet in our solar system where environmental modification now seems feasible – are not absolutely essential to humankind’s survival. But the successful terraforming of that world could make possible a reasonable facsimile of an Earth-like existence for a sizable population. While much of the work of terraforming Mars would be done by robots, humans overseeing this effort would be largely confined to underground habitats perhaps built into extinct lava tubes to protect them from galactic cosmic rays. However, technological advances in high-temperature superconductors might enable the construction of giant artificial magnetic shields to insulate all early settlements and allow their Earth-normal inhabitants to reside above ground and shed protective gear as long as they remained within the shielded environments.
Image: An artist’s impression of a terraformed Mars centered over Valles Marineris. The Tharsis region can be seen of the left side of the globe. Credit: Daein Ballard/Wikimedia Commons CC BY-SA 3.0.
Terraforming Mars would take a very long time and unfold in stages. The most distant from the Sun of the four terrestrial planets, Mars’s thin atmosphere is composed mostly of carbon dioxide. Its polar ice caps consist of a top layer of frozen carbon dioxide and a lower layer of water ice, and scattered elsewhere across areas of the planet are subsurface pockets of permafrost.
Evidence suggests that Mars once was home to at least one sizable ocean and that rivers of liquid water streamed across the planet’s surface and may exist underground today. More recent findings indicate that small streams of liquid water appear to flow on the surface during the planet’s warmer months. But steps could be taken to alter the trajectories of icy celestial objects to impact Mars at low velocities and deliver much of the water needed to create the vast reservoirs that would be critical to environmentally modifying that world. However, maintaining such liquid water reserves would first necessitate increasing the planet’s temperature and thickening its atmosphere.
In-space mirrors could be used to reflect additional sunlight on the planet and impacts by other celestial object could be engineered to help create a greenhouse effect that would warm the planet’s atmosphere and deliver the ammonia that would enable its nitrogen enrichment. Mars’s high carbon dioxide levels also could be utilized to help thicken its atmosphere.
Next, techniques could be employed to electrolyze some of the liquid water in the eventually created Martian seas. This would help produce the level of atmospheric oxygen required to sustain human as well as other Earth-indigenous animal life. What’s more, the process of passing an electrical current through water could be used to separate its hydrogen and oxygen components. Transformed into their separate gaseous states and then recombined in a combustion chamber, these components could serve to create energy for all types of uses.
After creating conditions to better retain atmospheric and surface heat, sections of Martian soil could be chemically and biologically treated and Earth-indigenous flora introduced to help produce even more atmospheric oxygen. However, it would be necessary to continuously work at enriching the oxygen content of the Martian atmosphere because of the planet’s weaker gravity, which poses special problems with respect to the escape time of gases.
In addition, Mars’s orbit around the Sun is more elliptical than Earth’s. It lacks a large satellite like Earth’s Moon and it is closer to giant Jupiter. These factors contribute to a periodic shift in the tilt of Mars’s axis, resulting in a destabilization of the Martian atmospheric composition, temperature and other environmental factors. Periodic corrective adjustments would be required.
Mars has half the radius of Earth and only one-tenth the mass, making the surface gravity on that world less than 40 percent of that on Earth. It has yet to be determined whether this level of gravity is sufficient to prevent the various health problems associated with weightlessness and how we would deal with these problems.
Surviving on an environmentally modified Mars could require genetic modifications to our species and other Earth-indigenous animal life forms. Genetically reengineered back on Earth, lower animal life forms would be introduced first and genetically modified humans later on. Modified humans and other animals might have larger eyes able to better function in an environment marked by reduced light from a more distant Sun. In addition, genetic alterations would be required for animal life to withstand higher levels of cosmic radiation in view of the fact that Mars lacks a substantial magnetic field to deflect incoming rays.
While many of our distant descendants will probably call Mars home, either below or possibly on the surface or aboard huge orbiting settlements, what will existence be like for others residing on the mobile world ships mentioned earlier? Such in-space habitats are likely to be of cylindrical or spherical shape, measure from less than one to as many as 10 kilometers in length or diameter and rotate around an axis so that their passengers on the inner rim can experience an analog of Earth-normal gravitation. If not as luxurious as those depicted in Hollywood’s fictional starships, the interior environments of these habitats will be comfortable enough. But tighter living quarters on the world ships could result in increased stress-related interpersonal issues among crew and passengers. Such ships will likely be totally recycling or resupplied using in-space resources, with only luxury items imported from Earth. Work is already underway to develop seeds that can grow into edible vegetables in only a few days and applications of 3D printing and more advanced technologies may one day enable the production of animal and other types of food products.
Destinations in the Galaxy
With the search for a new home world in interstellar space already underway, what kind of planet are we looking for and where do we expect to find it? Within our Milky Way Galaxy, there is a relatively narrow region called the galactic zone of life where life as we know could survive. Earth-like life could not survive in star systems located too close to the extremely dense and highly radioactive center of the galaxy, to dense star-forming regions with their high levels of radiation located elsewhere, or in regions in which certain higher elements are absent or in short supply. Moreover, the habitable zones surrounding individual stars in which Earth-like life could survive are also relatively narrow, and various factors would have to come into play in relation to suitable planetary bodies located within such zones to make them suitable for migration.
In interstellar space, we’re searching for planets of roughly Earth surface gravity located in the habitable zones of stable main sequence stars. Ideally, those planets will have day-night cycles similar to Earth’s and enough atmospheric oxygen to enable us to breathe, but not so much that combustion is uncontrolled. The average temperature on at least parts of the surfaces of those planets will have to be between the freezing and boiling points of water, which will have to be present on those worlds for humans and other terrestrial life forms to survive. Any life forms indigenous to those worlds should be more or less compatible with terrestrial life and not overly hostile. If indigenous DNA and proteins are similar to the varieties found on Earth today, virulent germs should be no more prevalent than here.
A cosmic event that could impact our interstellar migration involves the anticipated merger in four billion years or so of the Milky Way and Andromeda Galaxies. The two are part of a larger family of galaxies known as the Local Group, and the interplay of gravitational forces is expected to reconfigure them into a more massive galaxy elliptical in shape. Some models show the two merged galaxies absorbing the Triangulum Galaxy a few billion years later. While collisions between individual stars are expected to be rare, the stars in the merging galaxies will be thrown into different orbits around a new galactic center. There are many questions concerning how this reconfiguration might affect the timing and other aspects of our relocation from a dying solar system to a new home world orbiting another star.
Image: This illustration shows a stage in the predicted merger between our Milky Way galaxy and the neighboring Andromeda galaxy, as it will unfold over the next several billion years. In this image, representing Earth’s night sky in 3.75 billion years, Andromeda (left) fills the field of view and begins to distort the Milky Way with tidal pull. Credit: NASA; ESA; Z. Levay and R. van der Marel, STScI; T. Hallas; and A. Mellinger.
Emergence of Artificial Intelligence
The survival of the human species and other life forms indigenous to Earth will require the development of the technologies described throughout this narrative and the non-occurrence of some natural or man-made disaster severe enough to end all or most life on Earth before a more luminous Sun forces us to abandon our home planet. Our relocation is expected to first take us to the deeper reaches of our solar system, while computer-controlled robotic entities search for and then make ready for human habitation at least one new home world orbiting another star. And when our Sun begins to die, our survival will require that ships crewed by robots transport to that world the building blocks of human and other life forms for subsequent harvesting.
While it’s a stretch, at present, to envision humans ever traveling to the stars as functioning living beings because of the enormous distances involved, doing so in a state of suspended animation has been proposed. Suspended animation involves the slowing of life processes by external means without their termination. But the relocation of a sizable number of humans, either as functioning beings or in inanimate states aboard sleeper ships, could require many craft of considerable size, while a lesser number of ships of smaller size carrying the bio-diverse genetic building blocks of life could accomplish the same objective.
Barring the development of faster-than-light warp drive, the actualization of relativity theory wormhole short-cuts through space-time, or other currently theoretical applications of physics and engineering, the interstellar transport and later harvesting of the biological building blocks of human and other Earth-indigenous life forms would be the work of robotic entities, with oversight provided by a supercomputer capable of highly sophisticated cognitive computing.
But the time is not far off when “technological singularity” will make possible levels of artificial intelligence that are expected to surpass that possessed by today’s smartest human beings and most advanced computers – a time beyond which the course of animate human history becomes highly unpredictable. Might such levels of artificial intelligence decide to do away with animate humans because of their inability to keep pace with them? In that case, there will be no transporting of the biological building blocks of humankind to another star system.
Another idea envisions the eventual uploading of the human essence to computers. When the organic brains of humans begin to die, consciousness and memory would transfer to memory implants. The content of these implants would be input into a computational device and exist forever in some future equivalent of the virtual world. What would relocate to another star system would be the device and its contents, not human beings themselves.
Image: A human future among the stars may depend upon artificial intelligence we create. Credit: RAND Corporation.
But assuming that the interstellar transport and eventual harvesting of the biological building blocks of humankind by robots is what occurs, we can think of those robotic agents as electromechanical nannies charged with responding in nurturing ways to an infant or young child’s physical, intellectual and emotional needs and overseeing many of the complex requirements essential to a child’s early development and education. The supercomputer and robots that will be required to oversee all aspects of this transport and harvesting will need to possess capabilities that far exceed what is possible today.
The successful socialization of the first generation of humans harvested on some distant world would best be served by benign, non-living yet sentient-like robots called androids that simulate adult humans in appearance, behavior and speech. With the development of such entities already in progress, such computer-controlled machines will eventually possess human-like abilities to see, hear, taste, smell and touch.
The long-term survival of our species will require the development and intelligent use of innovative space propulsion systems, robotics, genetics, computers and information technology designed to spread terrestrial life beyond Earth and our solar system. While most of what has been discussed in this narrative lies in the distant future, it is a wondrous adventure upon which we have already embarked.
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The author greatly appreciates the extensive scientific and technical guidance provided by Gregory L. Matloff, PhD.
Building a space infrastructure is doubtless a prerequisite for interstellar flight. But the questions we need to answer in the near-term are vital. Even to get to Mars, we subject our astronauts to radiation and prolonged weightlessness. For that matter, can humans live in Mars’ light gravity long enough to build sustainable colonies without suffering long-term physical problems? Gregory Matloff has some thoughts on how to get answers, involving the kind of space facility we can build with our current technologies. The author of The Starflight Handbook (Wiley, 1989) and numerous other books including Solar Sails (Copernicus 2008) and Deep Space Probes (Springer, 2005), Greg has played a major role in the development of interstellar propulsion concepts. His latest title is Starlight, Starbright (Curtis, 2015).
by Gregory Matloff
The recent demonstrations of successful rocket recovery by Blue Origin and SpaceX herald a new era of space exploration and development. We can expect, as rocket stages routinely return for reuse from the fringes of space, that the cost of space travel will fall dramatically.
Some in the astronautics community would like to settle the Moon; others have their eyes set on Mars. Many would rather commit to the construction of solar power satellites, efforts to mine and/or divert Near Earth Asteroids (NEAs), or construct enormous cities in space such as the O’Neill Lagrange Point colonies.
But before we can begin any or all of these endeavors, we need to answer some fundamental questions regarding human life beyond the confines of our home planet. Will humans thrive under lunar or martian gravity? Can children be conceived in extraterrestrial environments? What is the safe threshold for human exposure to high-Z galactic cosmic rays (GCRs)?
To address these issues we might require a dedicated facility in Earth orbit. Such a facility should be in a higher orbit than the International Space Station (ISS) so that frequent reboosting to compensate for atmospheric drag is not required. It should be within the ionosphere so that electrodynamic tethers (ETs) can be used for occasional reboosting without the use of propellant. An orbit should be chosen to optimize partial GCR-shielding by Earth’s physical bulk. Ideally, the orbit selected should provide near-continuous sunlight so that the station’s solar panels are nearly always illuminated and experiments with closed-environment agriculture can be conducted without the inconvenience of the 90 minute day/night cycle of equatorial Low Earth Orbit (LEO). Initial crews of this venture should be trained astronauts. But before humans begin the colonization of the solar system, provision should be made for ordinary mortals to live aboard the station, at least for visits of a few months’ duration.
Another advantage of such a “proto-colony” is proximity to the Earth. Resupply is comparatively easy and not overly expensive in the developing era of booster reuse. In case of medical emergency, return to Earth is possible in a few hours. That’s a lot less than a 3-day return from the Moon or L5 or a ~1-year return from Mars.
A Possible Orbital Location
An interesting orbit for this application has been analyzed in a 2004 Carleton University study conducted in conjunction with planning for the Canadian Aegis satellite project [1]. This is a Sun-synchronous orbit mission with an inclination of 98.19 degrees and a (circular) optimum orbital height of 699 km. At this altitude, atmospheric drag would have a minimal effect during the planned 3-year satellite life. In fact, the orbital lifetime was calculated as 110 years. The mission could still be performed for an orbital height as low as 600 km. The satellite would follow the Earth’s terminator in a “dawn-to-dusk” orbit. In such an orbit, the solar panels of a spacecraft would almost always be illuminated.
For a long-term human-occupied research facility in or near such an orbit, a number of factors must be considered. These include cosmic radiation and space debris. It is also useful to consider upper-atmosphere density variation during the solar cycle.
The Cosmic Ray Environment
From a comprehensive study by Susan McKenna-Lawlor and colleagues of the deep space radiation environment [2], the one-year radiation dose limits for 30, 40, 50, and 60 year old female astronauts are respectively 0.6, 0.7, 0.82, and 0.98 Sv. Dose limits for men are about 0.18 Sv higher than for women. At a 95% confidence level, such exposures are predicted not to increase the risk of exposure-related fatal cancers by more than 3%.
Al Globus and Joe Strout have considered the radiation environment experienced within Earth-orbiting space settlements below the Van Allen radiation belt [3]. This source recommends annual radiation dose limits for the general population and pregnant women respectively at 20 mSv and 6.6 mGy (where “m” stands for milli, “Sv” stands for Sieverts and “Gy” stands for Gray). Conversion of Grays to Sieverts depends upon the type of radiation and the organs exposed. As demonstrated in Table 1 of Ref. 3, serious or fatal health effects begin to affect a developing fetus at about 100 mGy. If pregnant Earth-bound women are exposed to more than the US average 3.1 mSv of background radiation, the rates of spontaneous abortion, major fetal malformations, retardation and genetic disease are estimated respectively at 15%, 2-4%, 4%, and 8-10%. Unfortunately, these figures are not based upon exposure to energetic GCRs [3].
In their Table 5, Globus and Strout present projected habitat-crew radiation levels as functions of orbital inclination and shielding mass density [3]. Crews aboard habitats in high inclination orbits will experience higher dosages than those aboard similar habitats in near equatorial orbits. In a 90-degree inclination orbit, a crew member aboard a habitat shielded by 250 kg/m2 of water will be exposed to about 334 mSv/year. To bring radiation levels in this case below the 20 mSV/year threshold for adults in the general population requires a ~12-fold increase in shielding mass density [3].
But Table 4 of the Globus and Strout preprint demonstrates that, for a 600-km circular equatorial orbit, elimination of all shielding increases radiation dose projections to about 2X that of the habitat equipped with a 250 kg/m2 water shield. If shielding is not included and this scaling can be applied to the high-inclination orbit, expected crew dose rates will be less than 0.8 Sv/year [3]. This is within the annual dose limits for all male astronauts and female astronauts older than about 45 [2].
Early in the operational phase of this high-inclination habitat, astronauts can safely spend about a year aboard. Adults in the general public can safely endure week-long visits. Pregnant women who visit will require garments that provide additional shielding for the fetus. Some of the short-term residents aboard the habitat may be paying “hotel” guests. As discussed below, additional shielding may become available if development of this habitat is a joint private/NASA project.
Is Space Debris an Issue?
According to a 2011 NASA presentation to the United Nations Subcommittee on the Peaceful Uses of Outer Space, space debris is an issue of concern in all orbits below ~2,000 km. About 36% of catalogued debris objects are due to two incidents: the intentional destruction of Fengyun-1C in 2007 and the 2009 accidental collision between Cosmos 2251 and Iridium 33 [4].
The peak orbital height range for space debris density is 700-1,000 km. At the 600-km orbital height of this proposed habitat, the spatial density of known debris objects is about 4X greater than at the ~400 km orbital height of the International Space Station (ISS) [4]. As is the case with the ISS, active collision avoidance will sometimes be necessary.
Atmospheric Drag at 600 km
An on-line version of the Standard Atmosphere has been consulted to evaluate exospheric molecular density at orbital heights [5]. A summary of this tabulation follows:
Atmospheric Density, km/m2 at various solar activity levels
height
Low
Mean
Extremely High
400 km
5.68E-13
3.89E-12
5.04E-11
500
6.03E-14
7.30E-13
1.70E-11
600
1.03E-14
1.56E-13
6.20E-12
Note that atmospheric density levels at 600 km are in all cases far below the corresponding levels at the ISS ~400 km orbital height. But orbit adjustment will almost certainly be required during periods of peak solar activity.
Since the proposed 600-km orbital height is within the Earth’s ionosphere, there are a number of orbit-adjustment systems that require little or no expenditure of propellant. One such technology is the Electrodynamic Tether [6].
Habitat Properties and Additional Shielding Possibilities
A number of inflatable space habitats have been studied extensively or are under consideration for future space missions. Two that could be applied to construction of a ~600-km proto-colony are NASA’s Transhab and Bigelow Aerospace’s BA330 (also called B330).
Transhab, which was considered by NASA for application with the ISS and might find use as a habitat module for Mars-bound astronauts, would have a launch mass of about 13,000 kg. Its in-space (post-inflation) diameter would be 8.2 m and its length would be 11 m [7]. Treating this module as a perfect cylinder, its surface area would be about 280 m2. Transhab could comfortably accommodate 6 astronauts.
Image: Cutaway of Transhab Module with Crew members. Credit: NASA.
According to Wikipedia, the BA330 would have a mass of about 20,000 kg. Its length and diameter would be 13.7 m and 6.7 m, respectively. The Bigelow Aerospace website reports that the approximate length of this module would be 9.45 m. It could accommodate 6 astronauts comfortably during its projected 20-year operational life.
Both of these modules are designed for microgravity application. Since the study of the adjustment of humans and other terrestrial life forms to intermediate gravity levels might be one scientific goal of the proposed 600-km habitat, the habitat should consist of two modules arranged in dumbbell configuration connected by a variable-length spar with a hollow, pressurized interior. The rotation rate of the modules around the center could be adjusted to provide various levels of artificial gravity. Visiting spacecraft could dock at the center of the structure. It is possible that the entire disassembled and uninflated structure could be launched by a single Falcon Heavy.
Image: The pressurized volume of a 20 ton B330 is 330m3, compared to the 106m3 of the 15 ton ISS Destiny module; offering 210% more habitable space with an increase of only 33% in mass. Credit: Bigelow Aerospace.
One module could support the crew, which would be rotated every 3-6 months. The other module could accommodate visitors and scientific experiments. It is anticipated that visitors would pay for their week-duration experience to help support the project. Experiments would include studies of the effects of GCR and variable gravity on humans, experimental animals and experiments with in-space agriculture. The fact that the selected orbit provides near-constant exposure to sunlight should add a realistic touch to the agriculture studies. These experiments will hopefully lead to the eventual construction of in-space habitats, hotels, deep-space habitats and other facilities.
The possibility exists for cooperation between the developers of this proposed 600-km habitat and the NASA asteroid retrieval mission. Under consideration for the mid-2020’s, this mission would use the Space Launch System to robotically retrieve a ~7-meter diameter boulder and return it to high lunar orbit for further study [8]. The mass of this object in lunar orbit could exceed half a million kilograms. It is conceivable that much of this material could be used to provide GCR-shielding for Earth-orbiting habitats such as one considered here. As well as reducing on-board radiation levels, such an application would provide valuable experience to designers of deep-space habitats such as the O’Neill space colonies.
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References
1. S. Beaudette, “Carleton University Spacecraft Design Project; 2004 Final Design Report, “Satellite Mission Analysis”, FDR-SAT-2004-3.2.A (April 8, 2004).
2. S. McKenna-Lawlor, A. Bhardwaj, F. Ferrari, N. Kuznetsov, A. K. Lal, Y. Li, A. Nagamatsu, R. Nymmik, M. Panasyuk, V. Petrov, G. Reitz, L. Pinsky, M. Shukor, A. K. Singhvi, U. Strube, L. Tomi, and L. Townsend, “Recommendations to Mitigate Against Human Health Risks Due to Energetic Particle Irradiation Beyond Low Earth Orbit/BLEO”, Acta Astronautica, 109, 182-193 (2015).
3. A. Globus and J. Strout, “Orbital Space Settlement Radiation Shielding”, preprint, issued July 2015 available on-line at space.alglobus.net).
4. NASA, “USA Space Debris Environment, Operations, and Policy Updates”, Presentation to the 48th Session of the Scientific and Technical Subcommittee, Committee on the Peaceful Uses of Outer Space (7-9 February 2011).
5. Physical Properties of U.S. Standard Atmosphere, MSISE-90 Model of Earth’s Upper Atmosphere, www.braeunig.us/space/atmos.htm
6. L. Johnson and M. Herrmann, “International Space Station: Electrodynamic Tether Reboost Study, NASA/TM-1998-208538 (July, 1998).
Gregory Matloff is a major figure in what might be called the ‘interstellar movement,’ the continuing effort to analyze our prospects for travel to the stars. Greg is Emeritus Associate Professor and Adjunct Associate Professor in the Department of Physics at New York City College of Technology as well as Hayden Associate at the American Museum of Natural History. Centauri Dreams readers will know him as the author (with Eugene Mallove) of The Starflight Handbook (Wiley, 1989) and also as author or co-author of recent books such as Deep Space Probes (2005), Living Off the Land in Space (2007) and Solar Sails: A Novel Approach to Interplanetary Travel (2010). My own acquaintance with Greg’s work began with the seminal JBIS paper “Solar Sail Starships: The Clipper Ships of the Galaxy” (1981), and the flow of papers, monographs and books that followed have set high standards for those investigating our methods for going to the stars, and the reasons why we should make the attempt.
In the summer of 2011, Dr. Matloff delivered a paper in London at the British Interplanetary Society’s conference on the works of philosopher and writer Olaf Stapledon, the author of Star Maker (1937). One of Stapledon’s startling ideas was that stars themselves might have a form of consciousness. Greg’s presentation went to work on the notion in light of anomalous stellar velocities and asked what might make such an idea possible. His paper on the seemingly incredible notion follows. –PG
ABSTRACT
The Dark Matter hypothesis has been invoked as an explanation for the fact that stars revolve around the centers of their galaxies faster than can be accounted for by observable matter. After decades of failed experimental searches, dark matter has remained elusive. As an alternative to the Dark Matter hypothesis, a idea first presented by author Olaf Stapledon is developed in this paper. Stars are considered to be conscious entities maintaining their galactic position by their volition. It is shown that directed stellar radiation pressure and stellar winds are insufficient to account for this anomalous stellar velocity. Previous research rules out magnetism. A published theory of psychokinetic action that does not violate quantum mechanics is discussed, as is the suggestion that stellar consciousness could be produced by a Casimir effect operating on molecules in the stellar atmosphere. It is shown that a discontinuity in stellar velocities as a function of spectral class exists. Cooler red stars in the solar neighborhood move faster than hotter, blue stars, as would be expected if the presence of molecules in stars was a causative factor. Further research in experimentally validating the psychokinetic effect and demonstrating the role of the Casimir effect in consciousness is required to advance the concepts presented here beyond the hypothesis stage.
Introduction: Elusive Dark Matter
The motions of our Sun and other stars around the centers of their galaxies cannot be fully accounted for the presence of observable stellar or non-stellar matter. Possible modifications to Einstein-Newton gravitation do not seem appropriate since general relativity has easily passed every experimental test to date. Cosmologists hypothesize the existence of a non-reactive, non-observable but gravitating substance dubbed “dark matter” to account for the discrepancy. Dark matter seems to out-mass ordinary matter, according to many estimates [1].
But science requires observation or experimental validation for even the most beautiful of theoretical constructs. The continuing failure to detect or observe candidate dark matter objects or particles presents astrophysics with a very serious anomaly. Perhaps, as was the case in the late 19th century with the failure to confirm the ether hypothesis, the solution to the dark matter paradox may require a change in paradigm.
Image: Gregory Matloff (left) being inducted into the International Academy of Astronautics by Ed Stone.
Here, we reintroduce a 1937-vintage hypothesis of the British philosopher/science-fiction author Olaf Stapledon. In his monumental visionary novel Star Maker, Stapledon develops the thesis that stars are conscious and their motions around the galactic center are due to voluntary stellar adherence to the canons of a cosmic dance [2]. This is admittedly an extraordinary hypothesis. But if dark matter remains elusive and undetected no matter how expensive and elaborate the equipment seeking it, exotic alternatives cannot be dismissed out of hand.
Stellar Kinematics
Kinematics arguments presented here are elementary. Because of the low velocities (relative to the speed of light in vacuum), Newtonian dynamics is assumed. The reference frame is centered on the center of the Milky Way galaxy.
Following Newton’s Second Law, force is defined:
F = MA
where M = mass and A = acceleration. Linear momentum is defined:
P = MV
where V= a star’s orbital velocity around the galactic center and kinetic energy is defined as:
KE = 0.5MV2
The Sun revolves around the center of the Milky Way galaxy at ~220 km/s [3]. Let us posit that a solar-type star must alter its velocity by 100 km/s in 109 years by applying a non-gravitational force. This amounts to an acceleration of ~3 X 10-12 m/s2 or about ~3 X 10-13 g.
A solar-type star has a mass of about 2 X 1030 kg [5]. The (assumed) constant value of the non-gravitational force is about 6 X 1017 Newtons. While this seems like a huge force, it is roughly a million times less than the Sun’s gravitational force on the Earth.
Another means of considering this force’s magnitude is to assume that a 100-kg human is able to produce the same acceleration on herself during a 100-year lifetime. The average magnitude of this force on the human is about 3 X 10-10 N. During the person’s life, the force alters her velocity by about 0.01 m/s or 1 cm/s. This is far below the threshold of detection.
But what might be the cause of this elusive stellar force? Magnetism has been ruled out, at least for many astrophysical objects [4]. So we can consider two other physical candidates—a directed stellar wind and a unidirectional radiation pressure force.
Assume that a star can generate a continuous, unidirectional flux of ionized particles. The velocity of this “jet” is the typical solar wind velocity of 400 km/s. By the Conservation of Linear Momentum, the star must expel one-quarter of its mass in the uni-directional jet to alter its galactic velocity by 100 km/s. Such an astronomical event has never been observed and would be very disconcerting (most fatal) if it occurred on the Sun. The solar wind of ionized particles is clearly inadequate to alter a star’s velocity by 100 km/s.
Now let’s see if the radiation pressure on the star produced by its radiant output could produce a velocity change of 100 km/s in a billion years, if all the solar electromagnetic flux was concentrated in a narrow beam. If the star’s mass is equal to that of the Sun—2 X 1030 kg [5], the required change in stellar linear momentum amounts to about 7 X 1018 kg-m/s. If the star has a solar radiant output of about 4 X 1026 watts [5] and we apply the standard equation for a photon’s momentum (P) [6],
P = E/C
where E is the photon energy and c is the speed of light, we see that the total maximum radiation-pressure-induced linear-momentum change on the star is about 1.3 X 1018 kg-m/s. A star can clearly not affect the required linear momentum change in this fashion.
Magnetism, particle flow, and photon flow all fail to produce the required alteration in star kinematics. But there is at least one theoretical possibility that remains.
The Psychokinetic Option
One physically possible explanation for anomalous stellar motion is psychokinesis. The hypothesis is here presented that the “mind” of a conscious or sentient star can act directly upon the physical properties (in this case the galactic velocity) of that star.
Although no claim is made that psychokinesis (PK) is part of mainstream physics or psychology, at least one serious theoretical study indicates that it is possible within the currently accepted framework of quantum mechanics [7].
According to the arguments presented in Ref. 7, consciousness (or “mind”) can directly influence the properties of a physical system by utilizing the energy present in quantum mechanical fluctuations. Consciousness may do this by affecting collapse of the wave function of the system to the desired quantum state.
Such anomalous phenomena as alteration in the output of random number generators and levitation could be explained by such a process [7]. Although energy is conserved in this model of PK, the authors of Ref. 7 acknowledge possible violations of the second law of thermodynamics.
If a 2 X 1030 kg star changes its velocity by (a somewhat arbitrary) 100 km/s in a 109 year time interval using this technique, its kinetic energy changes by 1040 Joules and the average power required for the stellar velocity change is about 3 X 1023 watts. This is about 0.1% of the Sun’s radiant output.
In order to demonstrate that such a process could be applicable to stars, it is necessary to present arguments that at least some stars are conscious. Perhaps a good place to start is to consider what some researchers have said about consciousness in humans and other life forms.
Consciousness in Humans, Animals, Plants and Stars
Defining consciousness is not easy. We are all rather certain of our own consciousness and relatively convinced that other humans are conscious as well. Most would agree that whales, dolphins, chimps, cats and dogs are conscious organisms as well. But how about snakes, corn, amoeba, and bacteria? Do in fact the mechanisms that support consciousness in the higher animals, in fact, require billions of years of organic evolution to develop? Or does consciousness in some form permeate the entire universe?
Some, like Walker, conclude that consciousness cannot be defined. Instead, it must be thought of as the immediate experience of the world around us and our internal thoughts and emotions [8]. Bohm believes that conscious thought is a process rather than an object [9]. Kafatos and Nadeau argue that this process in some perhaps pantheistic sense permeates the entire universe [10]. Many theories have developed to fit this elusive phenomenon into the framework of physical science. Some are reviewed and developed in Refs. 11 and 12.
The concepts developed in this paper accept that consciousness, like gravitation, is built into the structure of the universe [10]. Like gravitation, it cannot be explained by invoking fields or matter independently but requires the interaction of both.
Many of the quantum-physics-based theories of organic consciousness postulate that a universal consciousness field interacts with electrically conducting nanostructures within the cell or nervous system. In higher animals (such as humans) the ~20-nm inter-synaptic spacing in the brain’s neuronal structure have been suggested and analyzed by Evan Harris Walker as locations of the quantum-level events contributing to consciousness [13]. But all living eukaryotic cells contain microtubules. As suggested by Lynn Margolis, a form of “microbial consciousness” may be centered upon these nano-structures [14].
Various quantum phenomena within these nanostructures have been suggested as the primary “active agents” of consciousness. These include quantum tunneling [13], quantum entanglement [15], and the Casimir Effect [16]. It is known that the Casimir Effect—a pressure caused by vacuum fluctuations—is a component of molecular bonds [17].
We propose the following Casimir-Effect approach to stellar consciousness. It is assumed that the interaction with vacuum fluctuations produces a form of consciousness in all molecular bonds, although this is weaker than the forms of consciousness affected by the interaction of vacuum fluctuations with organic nanostructures such as microtubules and the inter-synaptic spacing. Admittedly this is a pantheistic approach to the universe. All molecules to a certain extent are conscious. Stars cool enough to contain stable molecules are therefore conscious, at least to some extent. Over a very long period of time, they can apply psychokinetic effects to maintain their galactic position and remove at least some of the requirement for the thus-far undetected dark matter.
Some Evidence Supporting the Hypothesis of Conscious Stars
The ideas presented above might fit in the realms of philosophy and science fiction rather than physics unless there were some observational supporting evidence. A literature search was conducted to determine whether there is a kinematical discontinuity in stellar proper motion depending upon star surface temperature and occurring in the stellar spectral classes for which molecular lines and bands appear.
Since the 1950’s, such a discontinuity has in fact been recognized. Dubbed Parenago’s discontinuity, it refers to the fact that red, cooler stars have faster motions in the direction of galactic rotation than do blue, cooler stars. Figure 1 presents from two sources a plot of the solar motion of main sequence stars versus star B-V color index [18, 19]. The data set from Binney et al is derived from Hipparcos observations of more than 5,000 nearby stars [19].
Table 1 presents the spectral types corresponding to the B-V color indices on the abscissa of Fig. 1 [20]. The Parenago discontinuity occurs at around (B-V) = 0.6, which corresponds to early G dwarf stars such as the Sun. Note that estimated main sequence residence times for various spectral classes are also given in Table 1 [21].
TABLE 1 B-V Color Indices, Corresponding Spectral Classes and Main Sequence Residence Times for Dwarf Stars
Binney et al [19] present the hypothesis that the faster galactic velocities of cool, red, long-lived stars is due to the fact that gravitational scattering causes a star’s velocity to increase with age. This seems unlikely since F0 stars reside on the main sequence for a few billion years. In the Sun’s galactic neighborhood, stellar encounters close enough to alter stellar velocities are very rare due to the large star separations involved. For stellar encounters to cause Parenago’s discontinuity, these would likely occur while the stars were resident in the open cluster from which they originated. Since open clusters disperse within a few hundred million years [1], such stellar encounters seem to be an unlikely explanation for Parenago’s discontinuity.
The explanation presented here is based upon telescopic observations of molecules in the spectra of stars of various spectral classes. Molecules are rare or non-existent in the spectra of hot, blue stars. As star radiation temperature decreases, molecular signatures in stellar spectra become more apparent. In dwarf stars, N2 rises in abundance as photosphere temperature falls below 6000 K [22]. The spectral signature of CO is present in the Sun’s photosphere [23]. As stellar photosphere temperatures fall to around 3200 K (M2 stars), spectral signatures of many molecules including TiO and ZrO become observable in the infrared spectra [23].
Conclusions
Although it is provocative that Parenago’s stellar velocities around the galactic center increase with molecular abundance in the stellar photosphere, this paper does not claim to prove stellar consciousness as an alternative to dark matter. There are many other more conventional alternative explanations for anomalous stellar kinematics that must be considered as well [24].
But the validity of some of the assumptions presented here will be confirmed if future work demonstrates that PK effects can be reliably repeated in a laboratory environment. Other assumptions will be validated if future nano-scale computers achieve some level of consciousness when the size of computing elements reaches molecular levels.
If stellar consciousness can be demonstrated to be a reasonable dark matter alternative, major challenges will be presented to the SETI community. How exactly do we communicate with conscious, possibly sentient entities with lifetimes so long that a century seems like a second? And if we can’t do this successfully, how do we prevent the catastrophic wars between planetary and stellar intelligence in Star Maker as human interplanetary capabilities mature?
Some may argue in favor of Decartes’ separation of consciousness from the physical world. This approach is no longer valid at the molecular level since consciousness seems to be necessary for quantum mechanics and quantum mechanics is a well-validated physical theory [12].
Adam Crowl has pointed out to the author that the hypothesis presented here addresses one line of evidence for dark matter—the flatness of galactic rotation curves. A second line of evidence—observations that galactic clusters do not have enough visible mass to keep from dispersing—is not addressed by the arguments presented here [25].
Some may disagree with the inclusion of PK as a candidate “propulsion system” for conscious stars. As described in an excellent recent review by an MIT physics professor, this very controversial topic was investigated during the 1970’s by a distinguished group of theoretical physicists centered upon Stanford University. Debate still swirls regarding their courageous attempt to obtain mainstream support for their research [26].
Any scientific hypothesis must be falsifiable. The Hipparchos data used to prepare Ref. 19 utilized statistics for 5610 stars near the celestial south pole. According to the project’s website, the forthcoming ESA Gaia mission is planned to produce a kinematics census of a billion stars in the Milky Way galaxy. It will be interesting to learn whether this flood of data supports or refutes Parenago’s discontinuity.
Acknowledgements
The author appreciates the comments and suggestions of A. Crowl, which have been incorporated in the text. He is also grateful to K. Long who presented a version of this paper for him at the Nov. 23, 2011 Olaf Stapledon Symposium at BIS headquarters in London. Comments of anonymous referees are also appreciated.
References
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2. O. Stapledon, Last and First Men and Star Maker, Dover, NY (1968).
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4. F. J. Sanchez-Salcedo and M. Reyes-Ruiz, “Constraining the Magnetic Effects on HI Rotation Curves and the Need for Dark Halos,” Astrophysical Journal, 607, 247-257 (2004).
5. K. Lodders and B. Fegley Jr., The Planetary Scientist’s Companion, Oxford University Press, NY (1988).
6. A. Messiah, Quantum Mechanics, Wiley, NY (1958).
7. R. D. Mattuck and E. H. Walker, “The Action of Consciousness on Matter: A Quantum Mechanical Theory of Psychokinesis,” in The Iceland Papers, ed. A. Puharich, Essentia Research Associates, Amherst, WI (1979), pp. 111-160.
8. E. H. Walker, The Physics of Consciousness, Perseus Books, Cambridge, 8. MA (2000).
9. D. Bohm, Wholeness and the Implicate Order, Routledge & Kegan Paul, London, UK (1980).
10. M. Kafatos and R. Nadeau, The Conscious Universe, Springer-Verlag, NY (1990). Also see R. Penrose, The Emperor’s New Mind, Oxford University Press, NY(1989).
11. H. P. Stapp, Mind, Matter, and Quantum Mechanics, Springer-Verlag, NY (1993).
12. B. Rosenblum and F. Kuttner, Quantum Enigma: Physics Encounters Consciousness, Oxford University Press, NY (2006).
13. E. H. Walker, “The Nature of Consciousness,” Mathematical Biosciences, 7, 131-178 (1970).
14. L. Margulis, “The Conscious Cell,” in Cajal and Consciousness (Annals of the New York Academy of Sciences, Vol. 929), ed. P. C. Marijuan, pp. 55-70 (2001).
15. R. Penrose, “Quantum Computation, Entanglement and state Reduction,” Philosophical Transactions of the Royal Society, London A, 356, 1927-1939 (1998)..
16. B. Haisch, The God Theory, Weiser Books, San Francisco, CA (2006).
17. “Van der Waals Force,” www.wikipedia.org/wiki/Van_der_Waals_Force (accessed Oct. 22, 2011).
18. G. F. Gilmore and M. Zeilik, “Star Populations and the Solar Neighborhood,”” Allen’s Astrophysical Quantities, 4th ed., ed. A. N. Cox, Springer-Verlag, NY (2000), Chap. 19.
19. J. J. Binney, W. Dehnen, N. Houk, C. A. Murray and M. J. Preston, “The Kinematics of Main Sequence Stars from Hipparcos Data,” in Proceedings of the ESA Symposium ‘Hipparcos-Venice ’97,’ ESA SP-402, Venice, Italy 13-16 May 1997, pp. 473-477 (July, 1997).
20. J. S. Drilling and A. U. Landolt, “Normal Stars,” Allen’s Astrophysical Quantities, 4th ed., ed. A. N. Cox, Springer-Verlag, NY (2000), Chap. 15.
21. R. A. Freitas Jr., Xenology: An Introduction to the Scientific study of Extraterrestrial Intelligence and Civilization, 1st ed., Xenology Research Institute, Sacramento, CA (1979). http://www.xenology.info/xeno.htm.
22. L. H. Allen, “Interpretation of Normal Stellar Spectra,” Stellar Atmospheres, ed. J. L. Greenstein, Un1versity of Chicago Press, Chicago, ILL (1960), Chap. 5.
23. G. F. Sitnik and M. Ch. Pande, “Two Decay Processes for CO Molecules in the Solar Photosphere,” Soviet Astronomy, 11, 588-591 (1968).
24. S. Capozziello, L. Consiglio, M. De. Laurentis, G. De Rosa, and C. Di Donata, “The Missing Matter Problem: From the Dark Matter Search to Alternative Hypothesis,” arXiv:1110.5026v1 [astro-ph.CO] 23 Oct 2011.
25. A. Crowl, “Personal Communication” (Nov. 18, 2011).
26. D. Kaiser, How the Hippies Saved Physics, Norton, NY (2011).
The first conference devoted solely to worldships takes place today in London at the headquarters of the British Interplanetary Society. It seemed a good time to check in with Gregory Matloff, a man I described when writing Centauri Dreams (the book) as the ‘renaissance man of interstellar studies.’ Perhaps best known for his continuing work on solar sails, Matloff’s interests have nonetheless ranged widely. He brought deep space propulsion to a wide audience in his book The Starflight Handbook (1989), which covers the full spectrum of interstellar options, but for over three decades has continued to produce scientific papers investigating issues ranging from laser ramjets to beamed microwave missions. A recent interest has been the expansion of the human biosphere into space, as discussed in books like Paradise Regained: The Regreening of Earth (Springer, 2009) and the soon to be published Biosphere Extension: Solar System Resources for the Earth, written with C Bangs. These last titles indicate that the interest in worldships Matloff first cultivated in papers for JBIS in the early 1980s continues to burn bright, as the following will confirm.
PG: Greg, I know you have a paper slated for the worldship conference that the British Interplanetary Society is holding today in London even though you couldn’t be there in person. And I know you’ve also been drafted by the Benfords to give a talk at the 100 Year Starship conference coming up in Orlando in October. When I first surveyed the field for my Centauri Dreams book back in 2004, I learned you were one of the early voices on this intriguing concept, the idea that a spacecraft might become a vast habitat capable of carrying thousands, even hundreds of thousands, of people between the stars.
GM: I was one of the early scientific writers who addressed the idea. The concept itself goes back to the 1930s and even earlier. Worldships are mentioned in a philosophical essay by J. D. Bernal, The World the Flesh and the Devil (1929). There is also an absolutely wonderful science fiction novel by Olaf Stapledon called Starmaker (1937). He not only talks about world ships but also implies that stars themselves are conscious.
PG: The 1930s were an extraordinarily productive period both for science and science fiction.
GM: Extremely productive.There was a literary group at Oxford University that has become justly famous. C.S. Lewis and J.R.R. Tolkien took part in this, and Stapledon was often discussed. I would have loved to have been there to have heard these guys kicking their ideas around in the era before World War II, a time when they all knew what was coming. It must have been fabulous. The worldship idea then disappears, although Tsiolkovsky mentions it when talking about space greenhouses and things like that. He doesn’t really develop it, and nobody touches it to my knowledge until the 1970s.
Then came Dandridge Cole, before Gerard O’Neill comes onto the scene, talking about ‘macrolife’ and the possibility of hollowing out asteroids to create workable habitats. Gerard O’Neill himself is important because he takes the idea and makes it concrete. O’Neill had major people working for him, such as Brian O’Leary, who was an astronaut, and Thomas Heppenheimer, who becomes a well known space writer. Eric Drexler would became the co-founder of the field of nanotechnology. So these are very bright folks, and they worked with O’Neill on the space colonies. O’Neill somewhere in there quotes Stapledon, and Arthur Clarke refers to him as a true science fiction visionary. He’s referring to Starmaker.
Image: Dandridge Cole, who coined the term ‘macrolife’ to refer to human colonies in space and their evolution. Credit: Wikimedia Commons.
PG: Are worldships a theme in science fiction today?
GM: I found in the last 30 years maybe a couple of pieces, including Greg Benford and David Brin with Heart of the Comet (1986). People are hollowing out Halley’s comet and making it livable. The book also speculates about uploading of the human essence into a computer and things like that. What seems to have happened in science fiction in the last 20 or 30 years is to me many steps back. We’ve gone in the direction of military science fiction on the one hand and fantasy on the other. I go in looking for science fiction and would like to buy something but it’s very hard for me to find something in a Barnes & Noble that I’d like to buy. That to me is sort of depressing.
Looking Inward: Prospects and Consequences
PG: This seems to be a long way from the intense vision of the 1930s.
GM: Exactly. Now it is possible that we might be doing inward exploration rather than outward exploration. A recent book we purchased is How the Hippies Saved Physics, by David Kaiser (2011). The book talks about folks who started to apply quantum mechanics to human consciousness. It turns out C and I knew one of them fairly well, Evan Harris Walker, who died a few years ago. He was very much involved in this approach. I think what happened is that inward exploration, probably because of the 70s, had replaced outward exploration in many peoples’ minds. There may be some sense to it because people in the 70s thought they could do exploration by taking a pill or something similar. Later on learning how to do it by meditation and yoga comes to seem easier than funding a trillion dollar project to launch a few people into deep space.
PG: Just as setting up computerized VR is easier. Maybe we’re still going in the same direction.
GM: Yes, I think so. In fact, about two years ago, in October of 2009, C and I went to a meeting of singularity people. We were guests of Greg Benford. It was very interesting to hear these brilliant mathematicians talking about a virtual reality and folding human consciousness into it. Its a seductive thought. Now, is it more seductive than SETI? Is it more seductive than actually going out and colonizing new worlds or spreading the biosphere beyond the Earth — I don’t know!
I run into this with students all the time. Some of them are much more interested in inner exploration than outer exploration, and I don’t have any answers for this, except that I do hope that we also extend the biosphere, because I think it should be a goal of technological consciousness. It’s something we can do and it’s something we should do rather than having everybody just living in a little box. You and I may turn out to be in the minority on this.
Image: Olaf Stapledon, whose vision became a focal point for C.S. Lewis and J.R.R. Tolkien, and influenced Lewis’ subsequent science fiction, which was partly written in response to Stapledon’s ideas.
Near-Term Drivers for a Worldship
PG: Could be, but I suppose the worldship concept is sort of the ultimate extension of the expansion of the biosphere. Because these are gigantic vessels. Just how big are they?
GM: There are various estimates of the size of a worldship. If we’re talking about an interstellar ark, something that is like living in a submarine, it’s something that may be the size of a submarine. This is Edward Gilfillan in the 1970s
. The Outsiders are doing exactly that, traveling in worldships, and they consider it nearly low class to travel at a speed greater than one or two percent of the speed of light.
PG: I love that because it’s such a reversal of conventional thinking. Everyone is trying to go as fast as possible, and at the same time we all have the sense of short-term horizons. Here we’re saying, what’s your rush? And if we don’t get there in this generation, maybe we can in the next, or maybe in a hundred generations.
GM: Exactly. And that’s what they do. As I recall, the reason that terrestrials developed hyperdrive in these stories is that it’s a trade item for the Outsiders. They don’t care about things like that, but they’re trading for the things they want. Sure, hyperdrive is an interesting technique; it allows you to go fast if you want, but to us the voyage is the more important thing.
PG: I love the Niven stories of that era. Now you remind me I must go back and do some re-reading of those tales.
GM: Sure! They’re fabulous. And the more I think about it, the more significant science fiction is to science. Visionary science fiction is very, very important. People like Clarke, Asimov, Stapledon. Asimov does speculate that the early migrations from Earth are by worldships. He calls them interstellar arks.
PG: In which books?
GM: In the Foundation series, he does mention that the ruins of some of these arks are discovered around planets orbiting various stars, including one or two planets in the Alpha Centauri system, and they’re not sure where they come from. One of the speculations is that they come from Sol originally, 50,000 years ago. But the records have been lost.
The Worldship and the Sail
PG: Greg, although you are not going to London for the worldship conference, I know a paper of yours will be presented there on the question of using a sail for propusion. Tell us more about that.
GM: What has happened with the sail is that we know that solar sails are the only propulsion system for interstellar travel that people have suggested to date that can be used for acceleration, deceleration and cosmic ray shielding enroute. Because you simply wind it around the habitat. So it’s a tri-use device, which none of the others methods have. And what I do is I review a lot of the literature including acceleration and deceleration and I talk about the fact that right now the most investigated sail material is beryllium. People at NASA hate that.
Image: John Desmond Bernal, a British physicist and crystallographer whose The World, The Flesh & The Devil (1929) investigated a human presence in worldships and discussed the possibilities of solar sailing long before it became fodder for scientific papers.
Les Johnson [NASA MSFC] was at a conference in Aosta, I forget if that’s the one you were at, and when I described the work of a beryllium sail, he did a wonderful imitation of Indiana Jones and said, “Oh no, why did it have to be beryllium?” Because he’s making a very good point. If NASA wishes to build an Oort Cloud explorer which is going to be a small scale 2000 year ark — and in fifty or sixty years they could build this to demonstrate a prototype interstellar spacecraft and also to do exploration of the Oort Cloud — right now beryllium is their only candidate for the sail, but beryllium is also very toxic. Les was saying if we do this, we’re going to have to deal with huge losses and tremendous safety issues. I understood his point, but technology is changing very rapidly.
There are things like carbon nanotubes and more recently graphene. These are interesting because they could have thickness measured in nanometers. Maybe a couple of molecules thick. They would have a finite either reflectivity or absorptivity, which means even though they are extremely low in mass, they are very strong. They’re going to be pushed by photons. So you could certainly imagine lowering the interstellar transit time with the sail to something like a millennium, maybe even lower than that. I don’t know. I would hesitate to say that we’ve discovered everything.
PG: I actually remember Les saying that about beryllium two years ago in Aosta. But you’re saying that these possibilities are going to be significantly thinner than anything we might do with beryllium?
GM: I think they’ll be both thinner and stronger than what we’re doing with beryllium, and they may not be toxic to work with. Right now they are amazingly expensive. If you were going to come up with enough graphene to cover a postage stamp, it would cost something like a hundred million dollars. So to build a real starship would bankrupt the planet. Even if we paid it out over a century. So the graphene price has to come down by many orders of magnitude.
One person at the Aosta congress did suggest that this isn’t impossible because this is what happened with aluminum. Aluminum when it first became recognized as a possibly significant commercial metal, probably a century and a half ago, was remarkably expensive. But a number of commercial processes were developed and the price began to drop dramatically. And as it dropped, people found more and more applications, driving the price down still further.
PG: What sort of mission configuration would you foresee? We can talk about a close solar pass, but our colonists are not in any great rush anyway, are they?
GM: They’re not. If you are using graphene, you might even be able to start with something like Earth orbit to get there in a thousand years. Because it’s very, very thin. A lot depends upon how its reflectivity or absorptivity varies with temperature. We really don’t know much about this material at this point to any great depth. I’m going to be talking about this also in Orlando, and presenting some of the numbers one of the guys presented at Aosta. But it’s not something you can get your hand around at this point. It’s still a brand new material that’s extremely difficult to work with. It’s very expensive, and there are only a handful of labs on the planet that can fabricate the stuff. So right now it’s a scientific material but not yet an engineering material.
Life Within the Colossus
But I do think if you’re going to extrapolate how to engineer a worldship, you would think about something that is a small version of an O’Neill colony. It maybe has the dimensions of a small skyscraper, maybe a hundred meters high, twenty meters across. That’s the payload. The payload might mass something like 107 kilograms if it’s using a 2000 year beryllium sail, an inflatable sail, maybe the sail size is 600-700 kilometers.
PG: Huge sociological issues come into play when we’re talking about millennial voyages.
GM: Our crew would have to deal with interesting sociological matters. How do we become a society that stays intact for that long? And it was interesting that Arthur C. Clarke was not an optimist about the sociology. He was an optimist about the technology. In one of the Rama novels [in the series that began with Rendezvous with Rama, 1972], Rama was an alien worldship that comes to the solar system and aliens invite the terrestrials to fly a ship out and colonize it and live there with some of the aliens. Ultimately a few thousand terrestrials take advantage of this, and they have to decide how to live on this worldship. They decide to have a society with a lot of sports events, so they build stadiums for these. What happens is one of the major team players says I can take this place over. And he develops a cadre of fellows to work with him who enslave or massacre the other males and the various women become sex slaves.
He develops a fascist state with him on top. And what happens is one of the women revolts and she is able to get in contact with the worldship intelligence, which is the supreme intelligence of the universe, so she has a good deal of help, and because of this there is a very successful revolution. But OK. In any event, what Clarke is presenting there is pessimism about sociology and so was Heinlein in ‘Universe’/’Common Sense’ in the early 1940s. He has a worldship going between Earth and Centauri and the society falls apart. So basically all the people assume this is their universe. These two stories became the novel Orphans of the Sky, published as such in 1963.
It’s a brilliant story and of course the protagonists break in somehow to the holy of holies, the control room, they see what the stars are, they learn about the universe and they just happen to be passing through a solar system which is probably the Centauri system and there happens to be a livable planet. Somehow the shuttlecraft is operable by non-experts and they are able to elicit a landing. OK, Heinlein was playing the odds to have a happy ending to the thing, but the sociology is going to be a major factor because we haven’t had small human communities isolated for that long. There have been a couple of experiments and their results aren’t that good.
One of the experiments is the Vikings in Vinland. And when you look at that, the Vikings come and settle a small colony in Vinland [the account is told in the Saga of the Greenlanders]. One of the women is Freydis, the daughter of Erik the Red, who decides it’s too cold in the winter. She wants to be warmer, and why must she have only one male to snuggle up with? So she slaughters all her sisters and she has all the men now. This is in a small colony and they have nothing to do with the surrounding people, who they call Skraelings, the native Americans. So that’s an example maybe of a space colony gone wrong and becoming a tragedy.
Image: Robert Heinlein was one of a number of science fiction writers of his time who investigated the potential — and the problems — of worldships. Credit: The Heinlein Trust.
PG: On the other hand, I suppose one potential cause for optimism would be that a large enough worldship is going to have quite a large population, so perhaps that kind of diversity might play to survival. But I think the larger point you make is exactly in tune with the upcoming starship conference, mainly that while we usually think of interstellar ideas in terms of the propulsion that would get a probe there, the field actually demands a multidisciplinary approach.
GM: Very true. You make a good point about having a large population and I think O’Neill speculates that for a space habitat to be self-sufficient, it needs a population of something approaching a hundred thousand. Certainly tens of thousands of people. Then you have to say, what are they all going to do? If you have a large population like this, what will they do between stars? You have to design a ship in such a way that maybe the ship is never completely finished. Maybe the ecology always needs adjustment for it to work. Or maybe you have a second ship launched with materials to be mined as needed. Going out to the second ship and mining that becomes one of the periodical heroic episodes for this enclosed culture. Because look at the fact that we do seem to need heroes, in war or hopefully more frequently in sports. Look at the number of sports the industrialized and developed world practices today, and that’s to keep sane. That is largely to take the people who would be actual warriors and give them a role in society so they don’t have to go around other countries hacking off peoples’ heads.
A Multidisciplinary Study
PG: So all these things point us in the direction of the need to assess sociology, philosophy, history, to look at how humans have done in other settings when they’re in remote places.
GM: Yes. I would love to know the early history of the Minoan colonies in places like what is now Gaza. Or when the Minoan/Mycenaean peoples colonized Miletus in Asia Minor. Miletus becomes the parent for Russia, for many of the eastern European countries, because many of the people from there starting in about 1000 BC begin to build colony cities around the Black Sea area. I would love to know how many of these succeeded, how many failed, what the interaction was. Did they war with each other, did they war with the indigenous populations? I’m likewise fascinated with the early story of the Etruscans. They were obviously strongly influenced by the Minoan/Mycenaean civilization, but how did they do this? Were they a direct colony? We’ll probably never know. Or were they indigenous people who traded to try to build their own cities?
PG: You mentioned the possibility of having a second ship that might have resources the first could exploit. Is there an argument to be made that human nature says in any case a second ship is a good idea because you need to have a neighbor, a potential other, out there with you?
GM: It’s a possibility, that you might send instead of one ship a small fleet, particularly if you’re using something like a solar sail or a photon sail or maybe even an electric sail — you don’t have to pay for the propulsion. And in either case like this, conceivably, you could send as many colonies or habitats as wanted to go. That may offer something like this, because they could trade with each other, maybe they could have political or athletic contests with each other, maybe even there could be some form of highly ritualized warfare. I know that warfare among some of the native American population was initially very ritualized in just such a fashion. So we might be able to find all types of possible models in history and pre-history to go with.
PG: This discussion harkens back to that wonderful 1983 conference Interstellar Migration and the Human Experience, where you did have a very multidisciplinary group coming together to look at this kind of question, relating the topic to events like the settlement of the Pacific islands.
GM: Yes, that’s exactly what Ben Finney did. Unfortunately, I was not at that conference [held at Los Alamos in 1983], and always wish I had been. I’ve never met Ben Finney and would like to. I’m hoping he’s at the 100 Year Starship conference.
PG: Same here. I’m looking forward to seeing you at that conference, Greg, and want to thank you for your time this evening. As always, it has been a pleasure to talk to you.
Addendum: Kelvin Long sends via his smartphone this shot of the lunching worldship conference crew at the BIS headquarters where, as I post this (1600 UTC), the event should be just wrapping up.
In Centauri Dreams, Paul Gilster looks at peer-reviewed research on deep space exploration, with an eye toward interstellar possibilities. For many years this site coordinated its efforts with the Tau Zero Foundation. It now serves as an independent forum for deep space news and ideas. In the logo above, the leftmost star is Alpha Centauri, a triple system closer than any other star, and a primary target for early interstellar probes. To its right is Beta Centauri (not a part of the Alpha Centauri system), with Beta, Gamma, Delta and Epsilon Crucis, stars in the Southern Cross, visible at the far right (image courtesy of Marco Lorenzi).
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