Suppose you want to migrate to another star, taking your entire civilization with you. Not an easy task given our technology today, but let’s remember that in the 13 billion year-plus history of the Milky Way, countless stars and their planets have emerged that are far older than our 4.6-billion year old Sun. If we imagine an intelligence that survives for a billion years or more, we can hardly put constraints on what it might accomplish. The idea of moving a star with its planetary system intact is out there on the edge of what science fiction can accomplish, if not yet science. There have even been SETI searches for such projects, though as with SETI at large, no hits. Why would you want to move a star? Consider that if you are a long-lived species with a simple interest in exploring the universe, setting up a journey in which you can take your culture with you – all of it – could have serious appeal. For one thing, you are also taking your primary energy source with you, and can...

I think gravitational wave astronomy is one of the most exciting breakthroughs we’re tracking on Centauri Dreams. The detection of black hole and neutron star mergers has been a reminder of the tough elasticity of spacetime itself, its interplay with massive objects that are accelerating. Ripples in the fabric of spacetime move outward from events of stupendous energy, which could include neutron star mergers with black holes or other neutron stars. Earth-based observing projects like LIGO (Laser Interferometer Gravitational-Wave Observatory), the European Virgo and KAGRA (Kamioka Gravitational Wave Detector) in Japan continue to track such mergers. But there is another aspect of gravitational wave work that I’m only now becoming familiar with. It’s background noise. Just as ham radio operators deal with QRN, which is the natural hum and crackle of thunderstorms and solar events, so the gravitational wave astronomer has to filter out what is being called the astrophysical...

If space is infused with ‘dark energy,’ as seems to be the case, we have an explanation for the continuing acceleration of the universe’s expansion. Or to speak more accurately, we have a value we can plug into the universe to make this acceleration happen. Exactly what causes that value remains up for grabs, and indeed frustrates current cosmology, for something close to 70 percent of the total mass-energy of the universe needs to be comprised of dark energy to make all this work. Add on the mystery of ‘dark matter’ and we actually see only some 4 percent of the cosmos. So there’s a lot out there we know very little about, and I’m interested in mission concepts that seek to probe these areas. The conundrum is fundamental, for as a 2017 study from NASA’s Innovative Advanced Concepts office tells me, “...a straightforward argument from quantum field theory suggests that the dark energy density should be tens of orders of magnitude larger than what is observed.” Thus we have what is...

It's good now and then to let the imagination soar. Don Wilkins has been poking into the work of Carlo Rovelli at the Perimeter Institute, where the physicist and writer explores unusual ideas, though perhaps none so exotic as white holes. Do they exist, and are there ways to envision a future technology that can exploit them? A frequent contributor to Centauri Dreams, Don is an adjunct instructor of electronics at Washington University, St. Louis, where he continues to track research that may one day prove relevant to interstellar exploration. A white hole offers the prospect of even a human journey to another star, but turning these hypothesized objects into reality remains an exercise in mathematics, although as the essay explains, there are those exploring the possibilities even now. by Don Wilkins Among the many concepts for human interstellar travel, one of the more provocative is an offspring of Einstein's theories, the bright twin of the black hole, the white hole. The...

A friend and I were sitting in a diner some time back talking mostly about old movies (my passion is for black-and-white films from 1927 to the death of Bogart in 1957). Somehow the topic of gravity came up, I suspect because we had homed in on early 50’s science fiction films. Anyway, I remember his eyebrows raising when I mentioned how puny a force gravity was. I can understand why. We think about massive objects when we think about gravity, but of course it takes a lot of mass to get a little gravity. In fact, gravity is some 1038 times weaker than the strong force that holds atomic nuclei together, easily illustrated by pointing out to my friend that I was overcoming an entire planet’s worth of gravity by lifting the salt shaker on the table. I learned from Greg Matloff and Eugene Mallove’s The Starflight Handbook that despite Freeman Dyson’s early interest in using the gravitational force to capture energy from astronomical objects, it was Stanislaw Ulam who first pondered the...

What an intriguing thing to find Freeman Dyson’s “Gravitational Machines” paper popping up on arXiv. This one is yet another example of Dyson’s prescience, for in it he examines, decades before the actual event, how gravitational waves could be produced and detected, although he uses neutron stars rather than black holes as his focus. Fair enough. When this was written, in 1962, black holes were far more conjectural than they appear in most of the scientific literature today. But what a tangled history this paper presents. First of all, how does a 1962 paper get onto arXiv? A quick check reveals the uploader as David Derbes, a name that should resonate with Dyson purists. Derbes (University of Chicago Laboratory Schools, now retired) is the power behind getting Dyson’s lectures on quantum electrodynamics, first given at Cornell in 1951, into print in the volume Advanced Quantum Mechanics (World Scientific Publishing, 2007). He’s also an editor on Sidney Coleman’s Lectures on...

"'This,' said I at length, to the old man -- 'this can be nothing else than the great whirlpool of the Maelström'... The ordinary accounts of this vortex had by no means prepared me for what I saw. That of Jonas Ramus, which is perhaps the most circumstantial of any, cannot impart the faintest conception either of the magnificence, or of the horror of the scene -- or of the wild bewildering sense of the novel which confounds the beholder." So wrote Edgar Allen Poe in 1841 in a short story called "A Descent into The Maelström," reckoned by some to be an early instance of science fiction. In today's essay, Adam Crowl explores another kind of whirlpool, armed with the tools of mathematics to take the deepest plunge imaginable, into the maw of a supermassive black hole. Adam's always fascinating musings can be followed on his Crowlspace site. by Adam Crowl The European Southern Observatory’s (ESO) GRAVITY instrument is a beam combiner in the infra-red K-band that operates as a part of...

Moving propulsion technology forward is tough, as witness our difficulties in upgrading the chemical rocket model for deep space flight. But as we've often discussed on Centauri Dreams, work continues in areas like beamed propulsion and fusion, even antimatter. Will space drives ever become a possibility? Greg Matloff, who has been surveying propulsion methods for decades, knows that breakthroughs are both disruptive and rare. But can we find ways to increase the odds of discovery? A laboratory created solely to study the physics issues space drives would invoke could make a difference. There is precedent for this, as the author of The Starflight Handbook (Wiley, 1989) and Deep Space Probes (Springer, 2nd. Ed., 2005) makes clear below. by Greg Matloff We live in very strange times. The possibility of imminent human contraction (even extinction) is very real. So is the possibility of imminent human expansion. On one hand, contemporary global civilization faces existential threats from...

I see that Erik Lentz (Göttingen University) has just begun a personal blog, something that may begin to attract attention given that Dr. Lentz has offered up a new paper on faster than light travel. At the moment, the blog is bare-bones, listing only the paper itself (citation below) and an upcoming online talk that may be of interest. Here's what the Lentz blog has on this: Upcoming online talk to be given on 18 March 2021 at 3pm Eastern Standard Time for the Science Speaker Series at the Jim and Linda Lee Planetarium: https://youtu.be/6O8ji46VBK0 I checked the URL and found the page with a countdown timer, so I assume the event is publicly accessible. I would imagine it will draw a number of curious scientists and lay-people. On the subject of faster than light travel, much of the work in the journals has evolved from Miguel Alcubierre's now well known paper "The Warp Drive: Hyper-fast travel within general relativity," which presented the idea of a 'bubble' of spacetime within...

Harold “Sonny” White's investigations into controversial concepts like EMdrive and Alcubierre warp drive physics at Eagleworks Laboratories (located at the Johnson Space Center in Houston) received a good deal of attention in the interstellar community. In a recent email, Dr. White told me that he left NASA in December of 2019 and is now affiliated with the Limitless Space Institute, serving as its Director of Advanced Research and Development. The recently launched LSI is creating a series of initiative grants in support of interstellar research. What follows is the news release LSI has just released. Limitless Space Institute announces biennial Interstellar Initiative Grants (I2 Grants) Limitless Space Institute is launching biennial research grants with the goal of providing measurable and consistent support for pursuing interstellar research called Interstellar Initiative Grants. This call for proposals is seeking to support grants that can be categorized as either a tactical...

Avi Loeb’s new foray into the remote future had me thinking of the Soviet physicist Leonid Shkadov, whose 1987 paper “Possibility of Controlling Solar System Motion in the Galaxy” (citation below) discussed how an advanced civilization could get the Sun onto a new trajectory within the galaxy. Why would we want to do this? Shkadov could imagine reasons of planetary defense, a star being moved out of the way of a close encounter with another star, perhaps. All of this may remind science fiction readers of Robert Metzger’s novel CUSP (Ace, 2005), which sees the Sun driven by a massive propulsive jet. A more recent referent is Gregory Benford and Larry Niven’s novels Bowl of Heaven (Tor, 2012) and ShipStar (2014), in which a star is partially enclosed by a Dyson sphere and used to explore the galaxy. In 1973, Stanley Schmidt would imagine Earth itself being moved to M31 as a way of avoiding an explosion in the core of the Milky Way that threatens all life (Sins of the Fathers, first...

I always look at the NASA Innovative Advanced Concepts (NIAC) awards with interest as well as a bit of nostalgia. When I began researching the book that would become Centauri Dreams, NIAC was an early incentive. Then known as the NASA Institute for Advanced Concepts, it was under the direction of Robert Cassanova (this was back around 2002), and its archive of funded studies was a treasure house of deep space ideas, from antimatter extraction in planetary magnetic fields to exoplanet imaging through starshades. I spent days going through any number of reports and interviewed many NIAC study authors. You can still see the NIAC reports from that era on the older site (go to NIAC Funded Studies). The current NIAC site makes the point that the program looks for "non-traditional sources of innovation that study technically credible, advanced concepts that could one day 'change the possible' in aerospace." And it's here that we get the 2017 Phase 1 proposals, a $125,000 award for a nine...

The concluding part of the Tau Zero Foundation's examination of what is being called the 'EmDrive' appears today. It's a close analysis of the recent paper by Harold 'Sonny' White and Paul March in the Journal of Propulsion and Power. Electrical engineer George Hathaway runs Hathaway Consulting Services, which has worked with inventors and investors since 1979 via an experimental physics laboratory near Toronto, Canada. Hathaway's concentration is on novel propulsion and energy technologies. He has authored dozens of technical papers as well as a book, is a patent-holder and has hosted and lectured at various international symposia. Hathaway Consulting maintains close associations with advanced physics institutions and universities in the US and Europe. Those familiar with our Frontiers of Propulsion Science book will know his paper on gravitational experiments with superconductors, which closely examined past methods and cast a skeptical eye on early claims of anomalous forces (an...

Now that the EmDrive has made its way into the peer-reviewed literature, it falls in range of Tau Zero's network of scientist reviewers. Marc Millis, former head of NASA's Breakthrough Propulsion Physics project and founding architect of the Tau Zero Foundation, has spent the last two months reviewing the relevant papers. Although he is the primary author of what follows, he has enlisted the help of scientists with expertise in experimental issues, all of whom also contributed to BPP, and all of whom remain active in experimental work. The revisions and insertions of George Hathaway (Hathaway Consulting), Martin Tajmar (Dresden University), Eric Davis (EarthTech) and Jordan Maclay (Quantum Fields, LLC) have been discussed through frequent email exchanges as the final text began to emerge. Next week I'll also be presenting a supplemental report from George Hathaway. So is EmDrive new physics or the result of experimental error? The answer turns out to be surprisingly complex. by Marc...

Martin Tajmar's presentation at the American Institute of Aeronautics and Astronautics' Propulsion and Energy Forum and Exposition in Orlando yesterday has been getting plenty of press. Tajmar is looking at the device now commonly called an EmDrive, studied by Sonny White's team at Eagleworks (Johnson Space Center) and advocated by Roger Shawyer, Guido Fetta and Chinese experimenters as a way of producing thrust in a way that seemingly violates conservation of momentum. Tajmar (Dresden University of Technology) offers a paper entitled "Direct Thrust Measurements of an EmDrive and Evaluation of Possible Side-Effects" in his presentation on apparent thrust produced by the test device. As he told WIRED (which announced that The 'impossible' EmDrive could reach Pluto in 18 months), the current work will not close the story. From the paper itself: The nature of the thrusts observed is still unclear… Our test campaign can not confirm or refute the claims of the EmDrive but intends...

Sonny White's work on exotic propulsion has galvanized the press, as witness this story in the Daily Mail, one of many articles in newspapers and online venues. I was fortunate enough to be in the sessions at the 100 Year Starship Symposium where White, an engaging and affable speaker, described what his team at Eagleworks Laboratories (Johnson Space Center) is doing. The issue at hand is whether a so-called 'warp drive' that distorts spacetime itself is possible given the vast amounts of energy it demands. White's team believes the energy problem may not be as severe as originally thought. Here I'll quote Richard Obousy, head of Icarus Interstellar, who told Clara Moskowitz in Space.com: "Everything within space is restricted by the speed of light. But the really cool thing is space-time, the fabric of space, is not limited by the speed of light." On that idea hangs the warp drive. Physicists Michael Pfenning and Larry Ford went to work on Miguel Alcubierre's 1994 paper, the first...

SETI always makes us ask what human-centered assumptions we are making about extraterrestrial civilizations. When it comes to detecting an actual technology, like the starships we've been talking about in the last two posts, we've largely been forced to study concepts that fit our understanding of physics. Thus Robert Zubrin talks about how we might detect a magsail, or an antimatter engine, or a fusion-powered spacecraft, but he's careful to note that the kind of concepts once studied by the Breakthrough Propulsion Physics Project at NASA may be undetectable, since we really don't know what's possible and what its signature might be. I mentioned zero-point energy in a previous post because Zubrin likewise mentions it, an idea that would draw from the energy of the vacuum at the quantum level. Would a craft using such energies -- if it's even possible -- leave a detectable signal? I've never seen a paper on this, but it's true that one classic paper has looked at another truly exotic...

Anomalies are always fascinating because they cause us to re-examine our standard explanation for things. But in the case of the so-called 'Pioneer anomaly,' the Jet Propulsion Laboratory's Slava Turyshev, working with a group of scientists led by JPL's John Anderson, needed an explanation for practical reasons. The possibility that there was new physics to be detected had the scientists wondering about a deep space mission to investigate the matter, but missions are expensive and the case for a genuine Pioneer effect had to be strengthened or else put to rest. All of this led Turyshev to begin a multi-year data-gathering mission of his own, scouring records related to Pioneer wherever they might be found to see if what was happening to the spacecraft could be explained. The effect was tiny enough that it was originally dismissed as the result of leftover propellant in the fuel lines, but that explanation wouldn't wash. Something was causing the two Pioneers to decelerate back toward...

The news that the faster-than-light neutrino results announced to such widespread interest by the OPERA collaboration have now been explained has been spreading irresistibly around the Internet. But the brief piece in ScienceInsider that broke the news was stretching a point with a lead reading "Error Undoes Faster-Then-Light Neutrino Results." For when you read the story, you see that a fiber optic cable connection is a possible culprit, though as yet an unconfirmed one. Sean Carroll (Caltech) blogged on Cosmic Variance that while he wanted to pass the news along, he was reserving judgment until a better-sourced statement came to hand. I've thought since the beginning that a systematic error would explain the 'FTL neutrino' story, but I still was waiting for something with more meat on it than the ScienceInsider news. It came later in the day with an official CERN news release, and this certainly bears quoting: The OPERA collaboration has informed its funding agencies and host...

A paper in the December 24 issue of Physical Review Letters goes to work on the finding of supposed faster-than-light neutrinos by the OPERA experiment. The FTL story has been popping up ever since OPERA -- a collaboration between the Laboratori Nazionali del Gran Sasso (LNGS) in Gran Sasso, Italy and the CERN physics laboratory in Geneva -- reported last September that neutrinos from CERN had arrived at Gran Sasso's underground facilities 60 nanoseconds sooner than they would have been expected to arrive if travelling at the speed of light. The resultant explosion of interest was understandable. Because neutrinos are now thought to have a non-zero mass, an FTL neutrino would be in direct violation of the theory of special relativity, which says that no object with mass can attain the speed of light. Now Ramanath Cowsik (Washington University, St. Louis) and collaborators have examined whether an FTL result was possible. Neutrinos in the experiment were produced by particle...