Advancing Space Technology and Preparing for Contact with Extraterrestrial Intelligence through Multilateralism

Is it possible that we can account for the Fermi paradox by looking to our own behavior as a species? Some science fiction of the 1950s pointed in that direction, as witness The Day the Earth Stood Still (1951). Dr Kelvin F Long addresses the question in terms of the 'zoo hypothesis' in the essay below, asking what our culture could do to make itself less threatening to any outsider. Long is an aerospace engineer, astrophysicist and author. He leads the Interstellar Research Centre, a division of Stellar Engines, which conducts research on the science and technology associated with deep space exploration. He is a Chartered Member of the Institute of Physics and a Fellow of the British Interplanetary Society. He tells me he wrote this article as a means of fundamental protest at the current conflicts engulfing humanity and as a plea to any observing ETI not to judge our species by the immorality of those who hold power over the potential of humankind. Also available on his site are...

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Third Time’s a Charm: A Planet at Barnard’s Star

If you follow the fortunes of the stars closest to us, you know that Barnard’s Star has always excited interest, both because of its proximity to our system (about six light years) but also because of the early work on the star performed by Peter Van de Kamp at Sproul Observatory (Swarthmore College). That work, which ran until the early 1970s, initially appeared to show a Jupiter-class planet at the star but the results were later explained as instrumentation errors in Van de Kamp’s equipment. It was a cautionary tale, but credit the astronomer for working tirelessly using astrometry to attempt to validate a conclusion we now take for granted: There are planets around other stars. In 2018 we seemed to have a solid detection of a much different planet candidate via Guillem Anglada-Escudé (Queen Mary University, London) and Ignasi Ribas (Institute of Space Studies of Catalonia and the Institute of Space Sciences, CSIC in Spain), indicating a super-Earth of 3.3 Earth masses in an orbit...

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We Are the Music: Reflections on Galactic Immensity

While I’m immersed in the mechanics of exoplanet detection and speculation about the worlds uncovered by Kepler, TESS and soon, the Roman Space Telescope (not to mention what’s coming with Extremely Large Telescopes), I’m daunted by a single fact. We keep producing great art showing what exoplanets in their multitudes look like, but we can’t actually see them. Or I should say that the few visual images we have captured thus far are less than satisfying blobs of light marking hot young worlds. Please don’t interpret this as in any way downplaying the heroic work of scientists like Anne-Marie Lagrange (LESIA, Observatoire de Paris) on Beta Pictoris b and all the effort that has gone into producing the 70 or so images of exoplanets thus far found. I’m actually just pointing out how difficult seeing an exoplanet close up would be, for the goal of interstellar flight that animates our discussions remains hugely elusive. The work continues, and who knows, maybe in a century we’ll get a...

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Habitability around F-class Stars

Some years back I read a science fiction story in which the planet where the action took place orbited an F-class star. That was sufficiently odd to get my attention, and I began to pay attention to these stars, which represent on the order of 3 percent of all stars in the galaxy. Stars like our G-class Sun weigh in at about 7 percent, while the vast majority of stars are M-dwarfs, still our best chances for life detection because of the advantages they offer to our observing technologies, including deep transits and lower stellar brightness for direct imaging purposes. F-stars are intriguing despite the fact that they tend to be somewhat larger than the Sun (up to 1.4 times its mass) and also hotter (temperatures in the range of 6200-7200 K). Back in 2014, I looked at the work of Manfred Cuntz (University of Texas at Arlington), who had performed a study examining radiation levels in these stars and the damage that DNA would experience with an F-star in the sky at various stages of...

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The Long Afternoon of Earth

Every time I mention a Brian Aldiss novel, I have to be careful to check the original title against the one published in the US. The terrific novel Non-Stop (1958) became Starship in the States, rather reducing the suspense of decoding its strange setting. Hothouse (1962) became The Long Afternoon of Earth when abridged in the US following serialization in The Magazine of Fantasy & Science Fiction. I much prefer the poetic US title with its air of brooding fin de siècle decline as Aldiss imagines our deep, deep future. Imagine an Earth orbiting a Sun far hotter than it is today, a world where our planet is now tidally locked to that Sun, which Aldiss describes as “paralyzing half the heaven.” The planet is choked with vegetation so dense and rapidly evolving that humans are on the edge of extinction, living within a continent-spanning tree. The memory of reading all this always stays with me when I think about distant futures, which by most accounts involve an ever-hotter Sun and the...

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Beamed Propulsion and Planetary Security

Power beaming to accelerate a ‘lightsail’ has been pondered since the days when Robert Forward became intrigued with nascent laser technologies. The Breakthrough Starshot concept has been to use a laser array to drive a fleet of tiny payloads to a nearby star, most likely Proxima Centauri. It’s significant that a crucial early decision was to place the laser array that would drive such craft on the Earth’s surface rather than in space. You would think that a space-based installation would have powerful advantages, but two immediate issues drove the choice, the first being political. The politics of laser beaming can be complicated. I’m reminded of the obligations involved in what is known as the Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies (let’s just call it the Outer Space Treaty), spurred by a paper from Adam Hibberd that has just popped up on arXiv. The treaty, which comes out of...

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All the Light We Can See

I’ve reminisced before about crossing Lake George in the Adirondacks in a small boat late one night some years back, when I saw the Milky with the greatest clarity I had ever experienced. Talk about dark skies! That view was not only breathtaking on its own, but it also raised the point about what we can see where. Ponder the cosmic optical background (COB), which sums up everything that has produced light over the history of the universe. The sum of light can be observed with even a small telescope, but the problem is to screen out local sources. No telescope is better placed to do just this than the Long Range Reconnaissance Imager (LORRI) aboard the New Horizons spacecraft. Deep in the Kuiper Belt almost 60 AU from the Sun, the craft has a one-way light time of over eight hours (Voyager 1, by comparison, shows a one-way light time of almost 23 hours at 165 AU). It’s heartening that we’re continuing to keep the Voyagers alive even as the options slowly diminish, but New Horizons is...

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Green Mars: A Nanotech Beginning

I want to return to Mars this morning because an emerging idea on how to terraform it is in the news. The idea is to block infrared radiation from escaping into space by releasing engineered dust particles about half as long as the wavelength of this radiation, which is centered around wavelengths of 22 and 10 μm, into the atmosphere. Block those escape routes and the possibility of warming Mars in a far more efficient way than has previously been suggested emerges. The paper on this work even suggests a SETI implication (!), but more about that in a moment. Grad student Samaneh Ansari (Northwestern University) is lead author of the paper, working with among others Ramses Ramirez (University of Central Florida), whose investigations into planetary habitability and the nature of the habitable zone have appeared frequently in these pages (see, for example, Revising the Classical ‘Habitable Zone’). The engineered ‘nanorods’ at the heart of the concept could raise the surface temperature...

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The ‘Freakish Radio Writings’ of 1924

Mars was a lively destination in early science fiction because of its proximity. When H. G. Wells needed a danger from outer space, The War of the Worlds naturally looked toward Mars, as a place close to Earth and one with the ability to provoke curiosity. Closely studied at opposition in 1877, Mars provoked in Giovanni Schiaparelli the prospect of a network of canals, surely feeding a civilization that might still be alive. No wonder new technologies turned toward the Red Planet as they became available to move beyond visible light and even attempt to make contact with its inhabitants. All this comes to mind this morning because of an intriguing story sent along by my friend Al Jackson, whose work on interstellar propulsion is well known in these pages, as is his deep involvement with the Apollo program. Al had never heard of the incident described in the story. It occurred in 1924, when at another Martian opposition (an orbital alignment bringing Earth and Mars as close as they’ll...

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Pumping Energy into the Solar Wind

The solar wind is ever enticing, providing as it does a highly variable stream of charged particles moving out from the Sun at speeds up to 800 kilometers per second. Finding ways to harness that energy for propulsive purposes is tricky, although a good deal of work has gone into designs like magsails, where a loop of superconducting wire creates the magnetic field needed to interact with this ‘wind.’ But given its ragged variability, the sail metaphor makes us imagine a ship constantly pummeled by gusts in varying degrees of intensity, constantly adjusting sail to maintain course and stability. And it's hard to keep the metaphor working when we factor in solar flares or coronal mass ejections. We can lose the superconducting loop if we create a plasma cloud of charged particles around the craft for the same purpose. Or maybe we can use an electric ‘sail,’ enabled by long tethers that deflect solar wind ions. All of these ideas cope with a solar wind that, near the Sun, may be moving...

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Our Earliest Ancestor Appeared Soon After Earth Formed

Until we learn whether or not life exists on other planets, we extrapolate on the basis of our single living world. Just how long it took life to develop is a vital question, with implications that extend to other planetary systems. In today's essay, Alex Tolley brings his formidable background in the biological sciences to bear on the matter of Earth's first living things, which may well have emerged far earlier than was once thought. In particular, what was the last universal common ancestor -- LUCA -- from which bacteria, archaea, and eukarya subsequently diverged? Without the evidence future landers and space telescopes will give us, we remain ignorant of so fundamental a question as whether life itself -- not to mention intelligence -- is a rarity in the cosmos. But we're piecing together a framework that reveals Earth's surprising ability to spring into early life. by Alex Tolley Once upon a time, the history of life on Earth seemed so much simpler. Darwin had shown how natural...

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Are Interstellar Quantum Communications Possible?

A favorite editor of mine long ago told me never to begin an article with a question, but do I ever listen to her? Sometimes. Today’s lead question, then, is this: Can we expand communications over interstellar distances to include quantum methods? A 2020 paper by Arjun Berera (University of Edinburgh) makes the case for quantum coherence over distances that have only recently been suggested for communications: …We have been able to deduce that quantum teleportation and more generally quantum coherence can be sustained in space out to vast interstellar distances within the Galaxy. The main sources of decoherence in the Earth based experiments, atmospheric turbulence and other environmental effects like fog, rain, smoke, are not present in space. This leaves only the elementary particle interactions between the transmitted photons and particles present in the interstellar medium. Quantum coherence is an important matter; it refers to the integrity of the quantum state involved, and is...

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The Odds on an Empty Cosmos

When Arthur C. Clarke tells me that something is terrifying, he’s got my attention. After all, since boyhood I’ve not only had my imagination greatly expanded by Clarke’s work but have learned a great deal about scientific methodology and detachment. So where does terror fit in? Clarke is said to have used the term in a famous quote: “Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.” But let’s ponder this: Would we prefer to live in a universe with other intelligent beings, or one in which we are alone? Are they really equally terrifying? Curiosity favors the former, as does innate human sociability. But the actual situation may be far more stark, which is why David Kipping deploys the Clarke quote in a new paper probing the probabilities. Working with the University of Sydney’s Geraint Lewis, Kipping (Columbia University) has applied a thought experiment first conceived by Edwin Jaynes to dig into the matter. Jaynes (1922-1998)...

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The Final Parsec Paradox: When Things Do Not Go Bump in the Night

Something interesting is going on in the galaxy NGC 6240, some 400 million light years from the Sun in Ophiuchus. Rather than sporting a single supermassive black hole at its center, this galaxy appears to have two, located about 3000 light years from each other. A merger seems likely, or is it? Centauri Dreams regular Don Wilkins returns to his astronomical passion with a look at why multiple supermassive black holes are puzzling scientists and raising questions that may even involve new physics. By Don Wilkins Super massive black holes (SMBH), black holes with a mass exceeding 100,000 solar masses, don’t behave as expected. When these galaxies collide, gas and dust smash into each other forming new stars. Existing stars are too far apart to collide. The two SMBH of the galaxies converge. Intuition foresees the two massive bodies coalescing into a single giant, Figure 1. The Universe, as frequently happens, ignores our intuition. The relevant force is dynamical friction. [1-4] As a...

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The Search for Things that Matter

Overpopulation has spawned so many dystopian futures in science fiction that it would be a lengthy though interesting exercise to collect them all. Among novels, my preference for John Brunner’s Stand on Zanzibar goes back to my utter absorption in its world when first published in book form in 1968. Kornbluth’s “The Marching Morons” (1951) fits in here, and so does J.G. Ballard’s Billenium (1969), and of course Harry Harrison’s Make Room! Make Room! from 1966, which emerged in much changed form in the film Soylent Green in 1973. You might want to check Science Fiction and Other Suspect Ruminations for a detailed list, and for that matter on much else in the realm of vintage science fiction as perceived by the pseudonymous Joachim Boaz (be careful, you might spend more time in this site than you had planned). In any case, so strongly has the idea of a clogged, choking Earth been fixed in the popular imagination that I still see references to going off-planet as a way of relieving...

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On Ancient Stars (and a Thought on SETI)

I hardly need to run through the math to point out how utterly absurd it would be to have two civilizations develop within a few light years of each other at roughly the same time. The notion that we might pick up a SETI signal from a culture more or less like our own fails on almost every level, but especially on the idea of time. A glance at how briefly we have had a technological society makes the point eloquently. We can contrast it to how many aeons Earth has seen since its formation 4.6 billion years ago. Brian Lacki (UC-Berkeley) looked into the matter in detail at a Breakthrough Discuss meeting in 2021. Lacki points out that our use of radio takes up 100,000,000th of the lifespan of the Sun. We must think, he believes, in terms of temporal coincidence, as the graph he presented at the meeting shows. Note the arbitrary placement of a civilization at Centauri B, and others at Centauri A and C, along with our own timeline. The thin line representing our civilization actually...

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SPECULOOS-3b: A Gem for Atmospheric Investigation

“What is this fascination of yours with small red stars?” a friend asked in a recent lunch encounter, having seen something I wrote a few years back about TRAPPIST-1 in one of his annual delvings into the site. “They’re nothing like the Sun, to quote Shakespeare, and anyway, even if they have planets, they can’t support life. Right?” Hmmm. The last question is about as open as a question can get. But my friend is on to something, at least in terms of the way most people think about exoplanets. My fascination with small red stars is precisely their difference from our familiar G-class star. An M-dwarf planet bearing life would be truly exotic, in an orbit lasting mere days rather than months (depending on the class of M-dwarf), and perhaps tidally locked, so inhabitants would see their star fixed in the sky. How science fictional can you get? And we certainly don’t have enough data to make the call on life around any of them. Let’s talk a minute about how we classify small red stars,...

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Galactic Insights into Dark Matter

Put two massive galaxy clusters into collision and you have an astronomical laboratory for the study of dark matter, that much discussed and controversial form of matter that does not interact with light or a magnetic field. We learn about it through its gravitational effects on normal matter. In new work out of Caltech, two such clusters, each of them containing thousands of galaxies, are analyzed as they move through each other. Using data from observations going back decades, the analysis reveals dark and normal matter velocities decoupling as a result of the collision. Collisions on galactic terms have profound effects on the vast stores of gas that lie between individual galaxies, causing the gas to become roiled by the ongoing passage. Counter-intuitively, though, the galaxies themselves are scarcely affected simply because of the distances between them, and for that matter between the individual stars that make up each. We need to keep an eye on work like this because...

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On Astronomical Accidents, and the Proxima Centauri ‘Signal’ that Wasn’t

One night a few years back I had a late night call from a friend who was involved in Breakthrough Starshot, the attempt to design a probe that could reach nearby stars and return data with transit times of decades rather than centuries. His news was surprising. The Parkes radio dish in Australia, then being used by the Breakthrough Listen SETI project, had detected a signal that seemed to come from Proxima Centauri. “What’s interesting,” said he, “is that when you move the dish off Proxima, the signal disappears.” You probably remember this episode, which had a brief moment in the news and may well live on among the conspiracy-minded in the wackier regions of cyberspace. We know now that the signal was some form of radio frequency interference, commonly abbreviated RFI. In any case, our conversation was relatively tame because the idea of a terrestrial explanation seemed inevitable, no matter how tantalizing the first look at this signal. After all, with all the years of SETI effort...

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Science Fiction and the Interstellar Imagination

"We were dreamers, dreaming greatly, in the man-stifled town; We yearned beyond the sky-line where the strange roads go down. Came the Whisper, came the Vision, came the Power with the Need…" -- Kipling, from "The Song of the Dead" We’re lucky that science fiction fans are such packrats. They not only keep beloved books and magazine issues from their past but also catalog them relentlessly. Because of both these traits, I can turn to my own bookshelf and pull out the November, 1957 issue of Astounding Science Fiction to see P. Schuyler Miller’s review of John Campbell’s Islands of Space, in which he described the novel as “very characteristic of the best ‘hard’ science fiction of its day.” Miller had a lot to do in subsequent book reviews for the magazine with establishing ‘hard SF’ as a category. Campbell’s book, extensively revised from its original appearance in the spring, 1931 issue of Amazing Stories Quarterly, is an interesting curiosity in being the first appearance of a...

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Charter

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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If you'd like to submit a comment for possible publication on Centauri Dreams, I will be glad to consider it. The primary criterion is that comments contribute meaningfully to the debate. Among other criteria for selection: Comments must be on topic, directly related to the post in question, must use appropriate language, and must not be abusive to others. Civility counts. In addition, a valid email address is required for a comment to be considered. Centauri Dreams is emphatically not a soapbox for political or religious views submitted by individuals or organizations. A long form of the policy can be viewed on the Administrative page. The short form is this: If your comment is not on topic and respectful to others, I'm probably not going to run it.

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