Centauri Dreams

I was anticipating a particular punch-line in Michelle Nijhuis’ interesting article on communicating with extraterrestrials (Christian Science Monitor, May 15), and sure enough, it came where it should have, at the very end. Nijhuis quotes Jeffrey Lockwood (University of Wyoming): “In a sense, all writing is writing for extraterrestrials.” Lockwood, who teaches creative writing at the University of Wyoming, understands a deep truth. Communication between two people of the same species can be profoundly mysterious and often filled with misconceptions. How, then, would we ever communicate with an extraterrestrial culture?

Assume we receive, at long last, a signal from the stars that is unmistakably an attempt to communicate. After long debate, we decide to respond, describing who we are as a species. Which of these statements, drawn from a class Lockwood teaches on the subject, offers the best ten-word summary of the human condition?

• We are an adolescent species searching for our identity.
• Two arms, two legs, head, torso, symmetrical.

I rather like the first one. It offers up a measured view of who we are without the usual self-flagellation about our abundant failures. But the second message is clearly more valuable in conveying the basics, at least in terms of our physical natures. Lockwood’s class, funded by a NASA grant, questions how we make such a response, and the above answers came from an exercise in which he asked his students to reduce the human condition first to 250 words, then to fifty, then ten. But maybe fiction should be included in any response, or poetry, attempting to dig deeper not just into our biology but our philosophy, the view from inside the human head. Except how do we encode that view?

Douglas Vakoch, who ponders these matters for the SETI Institute, notes that the question of a human response could be triggered literally any day, if and when SETI delivers. Those of us who doubt this will happen, at least in our lifetimes, could find ourselves flat-footed if we don’t start pondering the range of possible answers, assuming we decide that sending an answer is indeed wise (that debate should be interesting). Vakoch has a hand in Lockwood’s class, having visited it and continuing to act as an advisor. He notes that “…it makes sense to start with writers. These are people who are really trying to express the human condition.”

This is one class I wish I could sit in on. When dealing with issues involving extraterrestrial contact, we need as broad a pool of opinion as possible. Lockwood’s students include not just writers but an accountant and a buffalo rancher, along with psychology majors and journalism students. The intellectual exercises they’re doing are useful even without any SETI contact, for in essence, the subject is how much we know about who we are, and how much of that we are willing to share. These are issues that go back to the dawn of history, but every human being looks at them anew, though seldom in a context so charged and enigmatic as first contact with another civilization.

Whether or not information can truly be lost is a major issue in the study of black holes. Stephen Hawking’s work in the 1970s offered a mechanism for black hole evaporation. Vacuum fluctuations would cause a particle and its antiparticle to appear just beyond the black hole’s event horizon, with one of the two falling into the black hole while the other escaped. A ‘virtual’ particle, in other words, would become a real particle. Black holes, in this view, would be able to lose mass through quantum effects, a theory that the soon to be launched GLAST satellite will try to confirm.

But ingenious as Hawking’s theory was, it produced a conundrum. Black holes that fail to gain more matter will eventually vanish, with information, such as the identity of matter drawn into the black hole, becoming permanently lost. It being a linchpin of quantum mechanics that information cannot be lost, this presents a problem. Enough of one that physicist John Preskill (Caltech) bet Hawking and Kip Thorne (also at Caltech) that information could not be lost in black holes. Hawking conceded in 2005, and now a team of physicists has suggested a new way of seeing black holes that would indeed allow information to escape.

Image: An artist’s depiction of the accretion of a thick ring of dust into a supermassive black hole. The accretion produces jets of gamma rays and X-rays. Credit: ESA / V. Beckmann (NASA-GSFC).

The idea behind this work, led by Abhay Ashtekar (Penn State), is that the disappearance of information is only an illusion. Think of spacetime as a series of individual building blocks. Ashtekar’s team believes that the idea of a continuum is but an approximation of a larger reality, one in which singularities, as Ashtekar himself says, “…are merely artifacts of our insistence that space-time should be described as a continuum.” Thus:

“Information only appears to be lost because we have been looking at a restricted part of the true quantum-mechanical space-time. Once you consider quantum gravity, then space-time becomes much larger and there is room for information to reappear in the distant future on the other side of what was first thought to be the end of space-time.”

The work, to be published in the Physical Review Letters, draws on mathematical studies of black holes in two dimensions, an approach the team believes accurately applies to real black holes in four-dimensions, although directly studying the latter is what Ashtekar and company are now proceeding to do. If confirmed, their work would validate Hawking’s decision to pay off the bet with Preskill, which he did by giving the physicist what he had asked for, a baseball encyclopedia. Thorne has yet to concede the bet, for Hawking’s own take on how black holes might leak information is as controversial as Ashtekar’s is likely to be.

A tricky aspect of modern astronomy is keeping all the wavelengths straight. Take the case of G1.9+0.3, a supernova remnant (SNR) near the center of the Milky Way. If you look at an X-ray image of this object made with the Chandra satellite in 2007, you’ll see clear signs of growth compared to what the Very Large Array saw in 1985. But the VLA was working at radio wavelengths, making the image comparison problematic. Scientists studying G1.9+0.3 therefore went back to the VLA to observe the object for a second time in order to verify their initial impression.

The later study confirmed that this supernova remnant — consisting of the materials ejected by the vast explosion — really is growing at what seems to be an unprecedented pace. Fifteen percent growth in 23 years is no small matter in astronomical terms, and the growth also makes it possible to work backwards in time to arrive at the time the supernova went off, now pegged at 150 years ago. That makes G1.9+0.3 the youngest of the 250 known supernova remnants in the Milky Way.

Image: The growth of supernova remnant G1.9+0.3 is clearly visible in this comparison shot. The colour scheme (dark blue -> light blue -> green -> yellow -> red) is increasing radio intensity. The width of each of the above images is about 3 arcmin, i.e. 1/20th of a degree. Credit: VLA/Dave Green.

Intriguingly, this SNR holds one other distinction: Its brightness at radio wavelengths has been increasing over the last few decades, a process unique among galactic supernova remnants. We’ll learn much from future observations. Says Dave Green (University of Cambridge):

“The discovery that G1.9+0.3 is so young is very exciting. It fits into a large gap in the known ages of supernova remnants, and since it is expanding so quickly, we will be able to follow its evolution over the coming years.”

Those observations will continue to be made at X-ray and radio wavelengths for now, the object being obscured by gas and dust so that it is not otherwise visible. Nor would the supernova that created it have been detectable to Victorian astronomers, buried behind dust lanes whose nature and location they did not yet suspect. The paper, accepted by Monthly Notices of the Royal Astronomical Society, is Green, Reynolds et al., “The radio expansion and brightening of the very young supernova remnant G1.9+0.3″ (abstract).

With the GLAST mission near launch, keep in mind the possibilities of this unique observatory in terms of findings that could revolutionize our view of distant events. GLAST (Gamma-Ray Large Area Space Telescope) will be looking at things we’ve only recently learned about, such as the enigmatic gamma-ray bursts (GRBs) now flagged by the Swift satellite and quickly pinpointed for the use of Earth-based observatories. We know we’re pushing into uncharted waters given that GLAST represents a major step forward over all previous satellites designed to study gamma ray events. And major new instruments usually deliver new classes of objects.

Because of the increase in GLAST’s sensitivity over earlier tools like the EGRET instrument on NASA’s Compton Gamma-ray Observatory (CGRO), the satellite may find thousands of new point sources. And we have plenty of questions already on the table. Gamma-ray bursts, for example, may be the result of black hole mergers, or the merger of a black hole and a neutron star. But it’s also thought that some are markers for the collapse of a massive star into a black hole. What types of stars, then, become GRB’s, and why? What is the mechanism for producing the initial gamma rays in the burst? Because GRBs seem to come in numerous varieties, their study offers fertile ground for years of research.

Or consider dark matter, the leading candidate for which is the hypothetical weakly interacting massive particle (WIMP). Gamma rays may also derive from WIMPS, which according to supersymmetry theory act as their own antimatter particles, annihilating when they interact with each other, and in the process releasing gamma rays and secondary particles. The signature of such annihilations is potentially observable with GLAST’s Large Area Telescope (LAT), assuming that dark matter is indeed composed of WIMPs. Its continuous stream of gamma rays should differ markedly from the milliseconds-to-minutes time frame of GRBs.

Image: According to supersymmetry, dark-matter particles known as neutralinos (which are often called WIMPs) annihilate each other, creating a cascade of particles and radiation that includes medium-energy gamma rays. If neutralinos exist, the LAT might see the gamma rays associated with their demise. Credit: Sky & Telescope / Gregg Dinderman.

One other fascinating possibility in range of this observatory is the question of the speed of light in a vacuum. The special theory of relativity pins the speed of electromagnetic radiation to 299,792,458 meters (186,282.4 miles) per second, and it would be assumed that gamma-ray photons should move at the same speed. Some models of quantum gravity, however, predict that the speed of very-high-energy gamma rays may vary slightly from other forms of light, the result of the turbulence of spacetime at quantum scales. GLAST can thus test a prediction that could nudge us, if only slightly, toward a merger of general relativity and quantum mechanics.

GLAST is now at Cape Canaveral with a planned launch in early June, having been moved to the Hazardous Processing Facility near Kennedy Space Center for fueling. I suppose it’s human nature that manned missions are what snare media attention, but this observatory may turn out to be one of the most significant we’ve launched in terms of probing out to the edges of physics and cosmology. Dark matter may not make CNN, nor will many gamma-ray bursts, but if GLAST can offer up some answers, we may get a far better read on how the universe functions, and if we’re really lucky, some clues to future propulsion possibilities.

How much would an extraterrestrial civilization resemble our own? The question resonates because on the one hand, the signature of our activities is what we tend to translate into the SETI search. We look, for example, for the signs of civilizations that are like us but more advanced technologically, which means we apply human thinking and motivations to cultures that are by definition not human. This is natural enough, because we’re the only technological civilization we know about, but it leads to results that may mislead us and obscure the actual situation.

Fermi’s Great Silence bothers us because we assume that what Milan Ćirković calls advanced technological civilizations (ATCs) will necessarily move out into the galaxy to colonize it. Yet we see no signs of this, no presence of an expansive power, no characteristic emissions telling us of any intelligence operating around nearby stars. This observation becomes a paradox only if we think in specifically human terms, relating what advanced cultures might do to our own history. If ATCs behave differently, then there may be no paradox — the galaxy may be rife with civilizations that simply operate according to a different set of principles.

Ćirković (Astronomical Observatory, Belgrade) continues to be one of our most innovative SETI thinkers, pushing well outside the conventional paradigm to ask what truly alien intelligence might do. And in an upcoming paper to be published in the Journal of the British Interplanetary Society, the astronomer also questions our own understanding of human history, asking whether expansive colonization is necessarily emblematic of our species. If it is not, we should not be so quick to rule out alternative scenarios for alien action. We might re-think an expansive colonial model in favor of one Ćirković calls the ‘city-state.’

Moving Beyond Biology

Imagine for a moment that as humanity and technology continue to intertwine, we move into a period when human capacities become extended so far beyond those of present day people that what is widely called a ‘posthuman’ civilization emerges. Would such a culture still be bound by biological motivations that characterize us today? Ćirković sees a contradiction in the thinking of many technological optimists, who support evolutionary explanations for mankind’s origin but seem unprepared to abandon the biological paradigm when considering what future civilizations might do when they move beyond it.

The situation seems to be as follows: if we agree that specific biological motivations have been a determining factor in the biological (human) phase of the history of our species, it would be only reasonable to argue that, with the transition to the postbiological (posthuman) phase, the old biological impetuses and motivations will become largely irrelevant. Paradoxically, it is rare to encounter such attitude in tech-optimists/transhumanist circles; in general, the predominant view is that the posthumanity will enable faster, better, larger, etc. steps toward achieving the same old, biological, Darwinian aims and goals. In other words, just new means toward old ends. I hereby argue that such view is old-fashioned, illogical and ultimately untenable. Rejecting it could throw some new light on issues in both future studies, as well as the discussions of advanced extraterrestrial civilizations and ongoing SETI projects.

That ‘new light’ considers the possibility that, as Sir Julian Huxley surmised in an essay written as far back as 1957, natural selection will have little to do with a true posthuman future. Instead, we have to look to other modes of evolution encompassing technological and cultural change. We may consider advanced technological civilizations as outcomes of such evolution that have now become immune to existential risks, societies that can manipulate the surrounding universe to a high level of precision, reaching what Nikolai Kardashev called a Type II level, able to use all the energy resources of their own planetary systems.

The Expanding Empire vs. the City-State

And because Ćirković questions what the expansive colonial model implies, he is drawn to ask what a Type II civilization would do with its power. The ‘city-state’ model is one focused on optimizing its activities, heeding the problems of further expansion and drawing heavily on its computational abilities. Rather than looking for signs of outward-reaching super-civilizations (much less Kardashev Type III societies, which Ćirković sees as unlikely to arise), we should ponder cultures that have a keen eye on their own limitations and an ability to use resources close at hand.

We’re in the area of postbiological evolution, as outlined here:

As an example, the imperative for filling the complete ecological niche in order to maximize one’s survival chances and decrease the amount of biotic competition is an essentially biological part of motivation for any species, including present-day humans… It would be hard to deny that this circumstance has played a significant role in colonization of the surface of the Earth. But expanding and filling the ecological niches are not the intrinsic property of life or intelligence – they are just consequences of the predominant evolutionary mechanism, i.e. natural selection. It seems logically possible to imagine a situation in which some other mechanism of evolutionary change, like the Lamarckian inheritance or genetic drift, could dominate and prompt different types of behaviour. The same applies for the desire to procreate, leave many children and enable more competitive transmission of one’s genes to future generation is linked with the very basics of the Darwinian evolution. Postbiological civilization is quite unlikely to retain anything like the genetic lottery when the creation of new generations is concerned.

The trick from the SETI perspective is to identify such a civilization, one without a pressing need for outward expansion beyond, perhaps, a few neighboring stellar systems. In fact, molecular nanotechnology might create such an efficient utilization of resources that an extraterrestrial culture would have little reason to look elsewhere, although Ćirković assumes that ATCs will, for reasons of research and prudence, become quite adept at monitoring the rest of the galaxy through a variety of observatories and nanotechnology-based interstellar probes. That model has a precedent in ancient Greek city-states that deployed networks of agents operating outside their own territories.

It’s a compelling argument, and you’ll find a rich science fiction treatment of some of its themes in Greg Egan’s Diaspora (1997), where a society of uploaded minds deals with the consequences of its freedom from biological motivations. Egan’s characters need not worry about their genetic heritage, their ecological boundaries, the pressures of population or any need for expansion through the colonial model. With access to information without the need of physical presence, the driving factors of the empire-state begin to dissipate. Even a dying star may not force expansion onto a culture like this, as Ćirković notes:

It has been claimed in the classical SETI literature that the interstellar migrations will be forced by the natural course of stellar evolution. However, even this “attenuated” expansionism – delayed by on the order of 10⁹ years – is actually unnecessary, since naturally occurring thermonuclear fusion in stars is extremely inefficient energy source, converting less than 1% of the total stellar mass into potentially useable energy. Much deeper (by at least an order of magnitude) reservoir of useful energy is contained in the gravitational field of a stellar remnant (white dwarf, neutron star or black hole), even without already envisaged stellar engineering. Highly optimized civilization will be able to prolong utilization of its astrophysically local resources to truly cosmological timescales.

Image: The globular cluster 47 Tucanae, about 15,000 light years from Earth, and 120 light years across. The stars in 47 Tuc are about 10-12 billion years old, making them among the oldest stars in the galaxy (more than twice the age of our own sun). Could some of these stars be the home of non-expansive, ‘city-state’ civilizations? Credit: Southern African Large Telescope.

To Observe the Unobservable?

Ćirković goes on to make the case against galactic empire in terms of both feasibility and cost, probing as well both political and ethical reasons for the city-state model to prevail. But back to the SETI question: Just how observable would a civilization following the city-state model actually be? We may find that our current technology is unable to make such detections, these being cultures whose very efficiency and adaptability to local resources renders them all but invisible to us. We do, however, get at least some relief from the otherwise inexplicable paradox of Fermi.

The paper is Ćirković, “Against the Empire,” slated for publication in JBIS and now available online. This paper is a comprehensive distillation of transhumanist ideas looked at in provocative new ways, its application to SETI one that challenges the basic assumptions of our radio and laser surveys. You’ll find much to mull over and much to argue with here. I wonder, for example, whether the lack of observed Type III civilizations in our cosmological neighborhood is truly a sign that galactic empires cannot form. Perhaps a Type III culture, able to harness the resources of its entire galaxy, would be even more difficult to detect than a nearby Type II, operating as it would be under assumptions that are even more alien to us than Ćirković’s city-states.

But opening up SETI to inquiries like these is heartening in many respects, and will be even more so if we continue to find no sign of intelligent life after another few decades. The astrobiological evidence thus far points in the direction of widespread life. If intelligence does arise on a modestly frequent basis, we may be living in a galaxy filled with thought whose pooled knowledge is simply unobservable, at least at this juncture of our own development. The thought that we are not alone, even if we are in the presence of moderate and sustainable societies much unlike our own, offers a satisfactory resolution to Fermi and a provocative picture of a possible (post)human future.

Alan Boyle uses the occasion of Neal Turok’s appointment as executive director of the Perimeter Institute for Theoretical Physics to interview the scientist on topics dear to the heart of Centauri Dreams readers. The ekpyrotic universe idea championed by Turok uses the idea of multidimensional ‘branes’ whose occasional collisions spark events like the Big Bang. A cyclic model emerges that sees multiple ‘bangs,’ using today’s accelerating universe as a condition for the arrival of the next cycle. It’s fascinating stuff, but does it assume the eventual validation of string theory? Boyle quotes Turok:

“In my opinion, string theory is the most promising avenue we have for the unification of gravity and the fundamental forces. But that doesn’t mean I’m not critical of it. I think sometimes people do exaggerate its achievements thus far. We need to keep an open mind.”

Turok, as director of Cambridge University’s Center for Theoretical Cosmology, worked with Princeton’s Barry Steinhardt on Endless Universe: Beyond the Big Bang (Doubleday, 2007), which belongs on your bookshelf. Did an exhausted earlier universe help to spawn the one we live in today, and is another one likely to form a trillion years from now? Don’t look for experimental evidence any time soon, but the ekpyrotic universe is a model whose startling conclusions may offer insights into both dark matter and energy, and the role of each in the universe’s growth. Ekpyrotic, incidentally, derives from the Greek word for ‘conflagration.’

Other weekend reading might involve the latest Carnival of Space, held this week at the Space Cynics site. This week I’ll send you to Bad Astronomy’s essay on the role our position in the galaxy may play in mass extinctions. This is Phil Plait’s take on a story we looked at briefly here on Centauri Dreams , involving the Solar System’s passage through the galactic plane, which may trigger a rain of comets from the outer system to move toward the Sun. So, at least, says a team at the Cardiff Centre for Astrobiology, which can point to our current galactic position as a sign that we may be nearing another such period. Check as well Brian Wang’s treatment of the laser comb technology we looked at yesterday.

Boosting the sensitivity of our exoplanet search tools by a hundredfold is no small matter, yet that’s just what optical frequency combs, when implemented with an ultrafast laser, may be able to do. A frequency comb is created by a laser that generates short, equally spaced pulses of light. ‘Locking’ the individual frequencies — keeping them in phase with each other — is essential, as is producing pulses that are no more than a few million billionths of a second long. The image below explains the name, the graph giving the impression of nothing more than a fine-toothed comb (and see this National Institute of Standards and Technology backgrounder for further details on how these combs work).

We’ve looked at laser combs before, in particular in the work being performed at the Harvard Smithsonian Center for Astrophysics, which is involved in the deployment of such a comb at the William Herschel Observatory in the Canary Islands. The resultant instrument, called the HARPS-NEF (High-Accuracy Radial-velocity Planet Searcher of the New Earths Facility) spectrograph, should be useful in studying Earth-sized planets detected by the Kepler mission. The spikes on the comb can be used to measure the frequency of other light sources to a high degree of precision, useful to everything from the exoplanet hunt to making more accurate global positioning measurements.

Image: Experimental data from a NIST “gap-toothed” frequency comb that are false colored to indicate the range from low power (red) to high power (blue). The comb is specially designed for astronomy. Each “tooth” is a precisely known frequency, and the teeth are widely separated (by 20 gigahertz) in comparison to a standard comb. Credit: M. Kirchner & S. Diddams/NIST.

Now scientists at the University of Konstanz in Germany and the National Institute of Standards and Technology (NIST) have pushed a laser into record territory with a combination of high speed, short pulses and high average power. The new laser produces pulses ten times more often than a standard NIST frequency comb, creating shorter pulses than other lasers operating at comparable speeds. This is significant because the shorter the laser pulses, the wider the spacing between the ‘teeth’ of the comb. While standard combs use teeth too closely spaced for precise exoplanetary work, an ultrafast laser in this range offers the potential for more precise measurements of distant light.

The interest in laser comb technologies stems from the need to improve our Doppler methods of planet detection. Tiny shifts in the frequency of a star’s light as measured on a spectrograph tell astronomers about the presence of an otherwise unseen planet around a star. The trick is to measure those shifts with ever increasing detail, an area in which frequency combs hold out rich promise. The shifts induced by an Earth-like planet — equivalent to a wobble of only a few centimeters per second — are far beyond the capabilities of today’s instruments, which are limited to about one meter per second.

No wonder, then, that laser combs are under study at a widening number of institutions, a list that also includes the Max-Planck Institute for Quantum Optics. The new ultrafast laser is one way to push the envelope. Another is to spread the ‘teeth’ of the comb using other methods. The above mentioned CfA work pursues these, and such techniques are also under investigation by the NIST group and Steve Osterman (University of Colorado, Boulder), who are working with sets of mirrors to eliminate periodic blocks of teeth to create a ruler that should be more than adequate for such minute planetary detections.

It’s hard enough to figure out what dark energy and dark matter are, a task that will occupy physicists for a long time to come. But even if we confine ourselves to ‘normal’ or ‘baryonic’ matter (accounting only for some four or five percent of the universe), we’re still left with a problem. Baryons are heavy subatomic particles like protons and neutrons that experience the strong nuclear force, and the problem is that even these relatively familiar particles are only partially accounted for.

So where is the missing baryonic matter? The answer may lie in a thin haze of hot, low-density gas that connects galactic clusters. Call it WHIM, for warm-hot intergalactic medium. Dutch and German scientists now think they have uncovered a filament of such gas that connects the clusters Abell 222 and Abell 223. The properties of the gas, visible primarily in the far ultraviolet and X-ray bands, fit with simulations in terms of density and temperature. The scientists used the XMM-Newton X-ray observatory to identify the hitherto unobserved filament.

Image: Composite optical and X-ray image of galaxy clusters Abell 222 and Abell 223. The cluster pair is connected by a filament permeated by hot X-ray emitting gas. The optical image was obtained by SuprimeCam at the Subaru telescope, the X-ray image showing the distribution of the diffuse hot gas (yellow to red) was obtained by XMM-Newton. Credits: ESA/ XMM-Newton/ EPIC/ ESO (J. Dietrich)/ SRON (N. Werner)/ MPE (A. Finoguenov).

Norbert Werner (SRON Netherlands Institute for Space Research), who led this work, thinks the team is seeing at least some of the missing baryonic matter. Says Werner, “The hot gas that we see in this bridge or filament is probably the hottest and densest part of the diffuse gas in the cosmic web…”

That last phrase deserves explanation. I’m working through the paper, which likens the structure of the universe to such a web-like structure, with galactic clusters, the largest objects in the universe, congregating at the web’s densest nodes. Let me quote the scientists on this:

According to the standard theory of structure formation, the spatial distribution of matter in the Universe evolved from small perturbations in the primordial density field into a complex structure of sheets and filaments with clusters of galaxies at the intersections of this filamentary structure. The filaments have been identified in optical surveys of galaxies…, but the dominant fraction of their baryons is probably in the form of a low density warm-hot gas emitting predominantly soft X-rays.

Sheets and filaments, with the things we see clustering in the web’s threads and knots. Thirty to forty percent of the baryonic matter in the universe ought to reside in filaments connecting galactic clusters, according to a variety of simulations, but this seems to be the first unambiguous detection (although other candidates have been put forward). And while the observed filament closely tracks at least one previous simulation, we still haven’t seen the largest part of the missing matter:

…according to the simulations… the dominant fraction of the WHIM resides in a lower temperature and density phase, the existence of which still remains to be proven observationally. The detection of the dominant fraction of the WHIM will only be possible with dedicated future instrumentation…

In other words, we’re going to need a more advanced space-based observatory to extend such difficult work, this particular filament being detectable largely because it is along the line of sight from Earth, thus concentrating its emission in a small region of sky. Understanding how matter is distributed in these structures will help us better piece together this web-like structure and the place of baryons within it.

The paper is Werner, et al., “Detection of hot gas in the filament connecting the clusters of galaxies Abell 222 and Abell 223,” Astronomy & Astrophysics Letters, Volume 482-3 (May, 2008), p. L29 (abstract).

By Larry Klaes

Any good news from Arecibo is welcome, and Larry Klaes here delivers it. The observatory, threatened with closure despite its key role in the hunt for Earth-crossing asteroids, may have found at least temporary deliverance. Politics seems to have played a role, as Larry notes, but for once with results that benefit science rather than compromising it. Meanwhile, a new study of the Chixculub impact 65 million years ago tells us that a hail of carbon cenospheres — tiny carbon beads — may have fallen planet-wide following the strike. The more we learn about past impacts, the more we realize how important a role our planetary radars play in forestalling future catastrophe.

What exists on the island of Puerto Rico that is over 1,000 feet across, could hold ten billion bowls of cereal, pick up a cell phone call from the planet Venus, once sent a message to any potential inhabitants of a distant globular star cluster, discovered the first planets around another star, has been a “star” in several major motion pictures, has spent the last two years under the threat of losing its funding, and now may be saved on several political fronts, including one involving a New York senator who has been rather busy these days running for President?

The answer is the Arecibo Observatory, which has been managed by Cornell University since it began exploring the Universe in 1963. Home to the largest single radio telescope on Earth, Arecibo has made many major discoveries for astronomy. The facility has also been prominent in analyzing planetoids known as Near Earth Objects (NEOs) that could potentially impact our planet and threaten all life upon it.

Despite all these achievements, in 2006 the National Science Foundation (NSF) appointed a senior advisory panel to see where they could get money for new astronomical projects by cutting funds from current projects. Arecibo was one of the larger targets for cuts, with a proposed removal of $2.5 million over the next few years. It became clear that if Arecibo could not find the financial resources from elsewhere, the venerable observatory could close down in 2011. Not only would this be a major loss to astronomy but also a blow to the economy of Puerto Rico and its important contribution to the science education of the population.

On April 14, the governor of Puerto Rico and the director of the National Astronomy and Ionospheric Center (NAIC) signed a $2.3 million agreement between the semi-autonomous United States territory and the agency that Cornell manages Arecibo through for the NSF. The “Inspiration to Science” program will allow tens of thousands of Puerto Rican school children to visit Arecibo annually to see how the observatory scientists work and receive personal instruction from facility staff consonant with their academic curricula. To handle this influx of students, two new teaching scientists and an aide will be hired. The Puerto Rico Department of Education will provide for the resource needs of the students participating in this program.

Image: Arecibo’s observatory appears to have new life ahead, a plus not only for observational science but the search for dangerous near-Earth objects. Credit: Lee Bennett/ATPM.

“For more than forty years, the Arecibo Observatory has been part of Puerto Rico, an icon recognizably identified with the island worldwide,” said NAIC Director Robert Brown at the signing ceremony. “With the agreement signed today, the people of Puerto Rico become fully part of the Arecibo Observatory, cementing a new relationship that will also become a proud heritage of Puerto Rico.”

As the “Inspiration to Science” initiative was inaugurated, another effort to save the Arecibo facility outright was launched thanks to the efforts of New York Democratic senator Hillary Rodham Clinton, who filed a bill to make the NSF reinstate its funding for the observatory.

Some residents noted that though the action by Clinton is welcome, the fact that it is happening less than two months before Puerto Rico’s final Democratic primary elections on June 1 leaves them wondering just how altruistic Clinton’s motivations were.

“Arecibo has been in peril for a while now,” said Andros Lopez to the Orlando Sentinel, an attorney and a co-director of the local campaign to elect rival Democratic candidate Barak Obama. “That she, by chance, finds about it now is an example of the type of old politics that Obama wants to change. The timing is more than suspect.” Lopez did add that he was grateful nevertheless to see that Clinton “finally pays attention to an issue that pertains to us.”

Arecibo Director Robert Kerr was just grateful for the Clinton’s desire to help the observatory, whatever the ultimate motivation.

“I am quite convinced that the excellence of the Arecibo Observatory will prevail,” declared Kerr regarding Clinton’s actions of support.

Senator Clinton’s Senate office published a release about her support for Arecibo, noting that “Cornell University scientists have used the remarkable tools available at Arecibo Observatory to greatly expand our understanding of the Universe. I am proud to support the path-blazing accomplishments of these New Yorkers.”

Regarding the actual stands of the major presidential candidates when it comes to science and space science in particular, Popular Mechanics recently reported on the candidates’ public declarations for national space policy and the reality behind their statements and motivations, which can be read online here.

A recent CNN report quoted experts in the space and military fields expressing the strong hope that the candidates will go beyond their spoken platitudes and address space policy in earnest soon. Not only are there political considerations to contend with in keeping America’s space program at the forefront, but having a robust ability to understand and monitor the Universe with such instruments as the Arecibo radio telescope – one of humanity’s greatest tools for studying and ultimately preventing NEOs that could strike Earth from hitting – is vital both for the United States and the rest of the world.

One of the world’s largest impact craters (see below) lies under Mexico’s Yucatan peninsula, evidently a major player in the demise of the dinosaurs. Chicxulub is 180 kilometers in diameter, the subject of continuing research by the man who identified it, Alan Hildebrand (University of Calgary). So you could say Hildebrand has an idea what massive impacts from asteroids can do to the Earth’s surface, having studied the environmental effects caused by this one and mapping the crater’s structure to identify mineral, oil and gas resources. That interest has led Hildebrand into an ongoing asteroid hunt, and explains his current plans to build and launch a space-based observatory designed to look for near-Earth objects.

The scientist currently uses use a retrofitted satellite tracking telescope in NEO work here on Earth. The instrument, based at the University of Calgary’s Rothney Astrophysical Observatory (some 75 kilometers southwest of the city) is an extensive re-build, a Cold War era instrument whose motors were replaced, its mount and optics modified and its electronics brought up to speed several years ago at the cost of $500,000. The telescope has been in asteroid-spotting use ever since.

Image: What we’re all hoping to avoid, an artist’s conception of a near-Earth object heating up as it encounters the upper atmosphere. Credit: Melinda Wenner/Wired Magazine.

Taking the asteroid search into space in the form of the Near Earth Object Surveillance Satellite (NEOSSat), an event that could occur within two years, would create the first space-based asteroid telescope, one to be used not only for identifying potential threats but also for helping us firm up our inventory of asteroids near enough to the Earth for manned missions. Nor is the suitcase-sized microsatellite a costly investment, totalling $10 million. Its position in space should allow the observatory to block sunlight to look for objects between the Earth and the Sun that are otherwise difficult to see.

Because some of these asteroids come close to matching Earth’s orbital speed, a robotic or manned asteroid mission becomes a distinct possibility. That would offer not only useful information about the early Solar System — such asteroids being remnants of same — but would also help us take the measure of the kind of objects we might one day need to push out of Earth-impacting trajectories. Would nukes work? Gravitational tugs? Sooner or later we’ll fly a NEO mission because we need to understand the nature of these asteroids as we assess the various strategies for dealing with them.

NEOSSat has the potential of cataloguing at least 50 percent of the one-kilometer or larger NEOs that orbit largely between Earth and the Sun, as New Scientist reports. Interestingly, the magazine cites Timothy Spahr (Harvard-Smithsonian Center for Astrophysics) as saying that an even better idea (though obviously far more expensive) would be to place a NEO-watching observatory in orbit around Venus, where the inventory of inner system objects could be even more definitively compiled.

Addendum: Although I had original identified Chixculub as the world’s largest impact crater, reader James Davis Nicoll quickly corrected me. Both Vredefort (300 km) and Sudbury (250 km) are larger.