Skeptophilia (skep-to-fil-i-a) (n.) - the love of logical thought, skepticism, and thinking critically. Being an exploration of the applications of skeptical thinking to the world at large, with periodic excursions into linguistics, music, politics, cryptozoology, and why people keep seeing the face of Jesus on grilled cheese sandwiches.
The list of confirmed exoplanets now exceeds six thousand. Considering the fact that the three main ways they're detected -- direct measure of stellar wobbles, transit photometry, and Doppler spectroscopy -- all require either that the host star be close, that the planets be massive, or that the planetary orbit be aligned just right from our perspective, or all three, it's almost certain that there are vast numbers of exoplanets going undetected.
All of which bodes well for those of us who would love for there to be extraterrestrial life out there somewhere.
On the other hand, of the exoplanets we've found, a great many of them are inhospitable to say the least, and some of them are downright bizarre. Here are a few of the weirder ones:
TrES-2b, which holds the record as the least-reflective planet yet discovered. It's darker than a charcoal briquet. This led some people to conclude that it's made of dark matter, something I dealt with here at Skeptophilia a while back. (tl:dr -- it's not.)
CoRoT-7b, one of the hottest exoplanets known. Its composition and size are thought to be fairly Earth-like, but it orbits its star so closely that it has a twenty-day orbital period and surface temperatures around 3000 C. This means that it is likely to be completely liquid, and experience rain made of molten iron and magnesium.
PSR J1719−1438, a planet orbiting a pulsar (the collapsed, rapidly rotating core of a giant star), and therefore somehow survived its host star going supernova. It has one of the fastest rates of revolution of any orbiting object known, circling in only 2.17 hours.
V1400 Centauri, a planet with rings that are two hundred times wider than the rings of Saturn. In fact, they dwarf the planet itself -- the whole thing looks a bit like a pea in the middle of a dinner plate.
BD+05 4868 Ab, in the constellation of Pegasus. Only 140 light years away, this exoplanet is orbiting so close to its parent star -- twenty times closer than Mercury is to the Sun -- that its year is only 30.5 hours long. This proximity roasts the surface, melting and then vaporizing the rock it's made of. That material is then blasted off the surface by the stellar wind, so the planet is literally evaporating, leaving a long, comet-like trail in its wake.
Today, though, we're going to look at some recent research about a planet that should be near the top of the "Weirdest Exoplanets Known" list. It's 55 Cancri Ae, the innermost of four (possibly six; two additional ones are suspected but unconfirmed) planets around the star 55 Cancri A, a K-type orange star a little over forty light years away. 55 Cancri Ae orbits its host star twice as close as Mercury does the Sun, making a complete ellipse around it in only a bit under three days. This means that like CoRoT-7b and BD+05 4868 Ab, it's crazy hot.
This is where some new research comes in. A presentation at an exoplanet conference in Groningen, Netherlands last week considered a puzzling feature of 55 Cancri Ae -- a measure of its heat output shows odd, non-cyclic fluctuations that don't seem to be in sync with its orbital period (or anything else). The fluctuations aren't small; some of them have approached a 1,000 C difference from peak to trough. They were first detected ten years ago, and physicists have been at a loss to account for the mechanism responsible.
But now, we might have an explanation -- and it's a doozy. Models developed by exoplanet astrophysicist Mohammed Farhat of the University of California - Berkeley found that the anomalous temperature surges could be explained as moving hotspots.
Which sounds pretty tame until you read Farhat's description of what this means. We're talking about a planet close in to a star not much smaller than the Sun, being whirled around at dizzying speeds. This means it's experiencing enormous tidal forces. The planet itself is so hot it's probably liquid down to its core. Result: tidal waves of lava several hundred meters high, moving at the speed of a human sprinter.
The presentation definitely got the attendees' attention. "This is right in the sweet spot of something that is interesting, novel, and potentially testable," said planetary astronomer Laura Kreidberg, of the Max Planck Institute for Astronomy. "I had this naïve idea that lava flows were too slow-moving to have an observable impact, but this new work is pointing otherwise."
The whole thing reminds me of the planet Excalbia from Star Trek, from the episode "The Savage Curtain," which was completely covered by churning seas of lava -- except for the spot made hospitable by some superpowerful aliens so Captain Kirk could have a battle involving Abraham Lincoln, Genghis Khan, and various other historical and not-so-historical figures to find out whether good was actually stronger than evil.
Put that way, I know the plot sounds pretty fucking ridiculous, but don't yell at me. I didn't write the script.
In any case, I doubt even the Excalbians would find 55 Cancri Ae hospitable. But it is fascinating. It pushes the definition of what we even consider a planet to be -- a sloshing blob of liquid rock with lava waves taller than a skyscraper. Makes me thankful for the calm, temperate climes of Earth.
I'll start today with a quote (often misquoted) from William Shakespeare -- more specifically, Hamlet, Act I, Scene 5:
Horatio:
O day and night, but this is wondrous strange!
Hamlet:
And therefore as a stranger give it welcome. There are more things in heaven and earth, Horatio, Than are dreamt of in your philosophy.
Horatio and Hamlet, of course, are talking about ghosts and the supernatural, but it could equally well be applied to science. It's tempting sometimes, when reading about new scientific discoveries, for the layperson to say, "This can't possibly be true, it's too weird." But there are far too many truly bizarre theories that have been rigorously verified over and over -- quantum mechanics and the General Theory of Relativity jump to mind immediately -- to rule anything out based upon our common-sense ideas about how the universe works.
That was my reaction while watching a YouTube video about an astronomical object I'd never heard of -- Przybylski's Star, named after its discoverer, Polish-born Australian astronomer Antoni Przybylski. The video comes from astronomer David Kipping's channel Cool Worlds Lab, which looks at cutting-edge science -- and tantalizing new data about the universe we live in. (You should subscribe to it -- you won't be sorry.) Przybylski's Star is 355 light years from Earth, in the constellation of Centaurus, and is weird in so many ways that it kind of boggles the mind.
It's classified as a Type Ap star. Type A stars are young, compact, luminous, and very hot; the brightest star in the night sky, Sirius, is in this class.
Przybylski's Star rotates slowly. I mean, really slowly. Compared to the Sun, which rotates about once every 27 days, Przybylski's Star rotates once every two hundred years. Most type A stars rotate even faster than the Sun; in fact, a lot of them rotate so quickly that the light from their receding hemisphere and that from their approaching hemisphere experience enough red-shift and blue-shift (respectively) to smear out their spectral lines, making it impossible for us to tell exactly what they're made of.
You probably know that most ordinary stars are primarily composed of hydrogen, and of the bit that's not hydrogen, most of it is helium. Hydrogen is the fuel for the fusion in the core of the star, and helium is the product formed by that fusion. Late in their life, many stars undergo core collapse, in which the temperatures heat up enough to fuse helium into heavier elements like carbon and oxygen. Most of the rest of the elements on the periodic table are generated in supernovas and in neutron stars, a topic I dealt with in detail in a post I did about six years ago.
My point here is that if you look at the emission spectra of your average star, the spectral lines you see should mostly be the familiar ones from hydrogen and helium, with minuscule traces of the spectra of other elements. The heaviest element that should be reasonably abundant, even in the burned-out cores of stars, is iron -- it represents the turnaround point on the curve of binding energy, the point where fusion into heavier elements starts consuming more energy than it releases.
So elements that are low in abundance pretty much everywhere, such as the aptly-named rare earth elements (known to chemists as the lanthanides), should be so uncommon as to be effectively undetectable. Short-lived radioactive elements like thorium and radium shouldn't be there at all, because they don't form in the core of your ordinary star, and therefore any traces present had to have formed prior to the star in question's formation -- almost always, enough time that they should have long since decayed away.
The composition of Przybylski's Star, on the other hand, is so skewed toward heavy elements that it elicits more in the way of frustrated shrugs than it does in viable models that could account for it. It's ridiculously high in lanthanides like cerium, dysprosium, europium, and gadolinium -- not elements you hear about on a daily basis. There's more praseodymium in the spectrum of its upper atmosphere than there is iron. Even stranger is the presence of very short-lived radioactive elements such as plutonium -- and actinium, americium, and neptunium, elements for which we don't even know a naturally-occuring nuclide synthesis pathway capable of creating them.
So where did they come from?
"What we’d like to know... is how the heavy elements observed here have come about," said astronomy blogger Paul Gilster. "A neutron star is one solution, a companion object whose outflow of particles could create heavy elements in Przybylski’s Star, and keep them replenished. The solution seems to work theoretically, but no neutron star is found anywhere near the star."
"[T]hat star doesn’t just have weird abundance patterns; it has apparently impossible abundance patterns," said Pennsylvania State University astrophysicist Jason Wright, in his wonderful blog AstroWright. "In 2008 Gopka et al. reported the identification of short-lived actinides in the spectrum. This means radioactive elements with half-lives on the order of thousands of years (or in the case of actinium, decades) are in the atmosphere... The only way that could be true is if these products of nuclear reactions are being replenished on that timescale, which means… what exactly? What sorts of nuclear reactions could be going on near the surface of this star?"
All the explanations I've seen require so many ad-hoc assumptions that they're complete non-starters. One possibility astrophysicists have floated is that the replenishment is because it was massively enriched by a nearby supernova, and not just with familiar heavy elements like gold and uranium, but with superheavy elements that thus far, we've only seen produced in high-energy particle accelerators -- elements like flerovium (atomic number 114) and oganesson (atomic number 118). These elements are so unstable that they have half-lives measured in fractions of a second, but it's theorized that certain isotopes might exist in an island of stability, where they have much longer lives, long enough to build up in a star's atmosphere and then decay into the lighter, but still rare, elements seen in Przybylski's Star.
There are several problems with this idea, the first being that every attempt to find where the island of stability lies hasn't succeeded. Physicists thought that flerovium might have the "magic number" of protons and neutrons to make it more stable, but a paper released not long ago seems to dash that hope.
The second, and worse, problem is that there's no supernova remnant anywhere near Przybylski's Star.
The third, and worst, problem is that it's hard to imagine any natural process, supernova-related or not, that could produce the enormous quantity of superheavy elements required to account for the amount of lanthanides and actinides found in this star's upper atmosphere.
Which brings me to the wildest speculation about the weird abundances of heavy elements. You'll never guess who's responsible.
Go ahead, guess.
There is a serious suggestion out there -- and David Kipping does take it seriously -- that an advanced technological civilization might have struck on the solution for nuclear waste of dumping it into the nearest star. This explanation (called "salting"), bizarre as it sounds, would explain not only why the elements are there, but why they're way more concentrated in the upper atmosphere of the star than in the core.
"Here on Earth... people sometimes propose to dispose of our nuclear waste by throwing it into the Sun,” Wright writes. “Seven years before Superman thought of the idea, Whitmire & Wright (not me, I was only 3 in 1980) proposed that alien civilizations might use their stars as depositories for their fissile waste. They even pointed out that the most likely stars we would find such pollution in would be… [type] A stars! (And not just any A stars, late A stars, which is what Przybylski’s Star is). In fact, back in 1966, Sagan and Shklovskii in their book Intelligent Life in the Universe proposed aliens might 'salt' their stars with obviously artificial elements to attract attention."
A curious side note is that I've met (Daniel) Whitmire, of Whitmire & Wright -- he was a professor in the physics department of the University of Louisiana when I was an undergraduate, and I took a couple of classes with him (including Astronomy). He was known for his outside-of-the-box ideas, including that a Jupiter-sized planet beyond the orbit of Pluto was responsible for disturbing the Oort Cloud as it passed through every hundred million years or so (being so far out, it would have a super-long rate of revolution). This would cause comets, asteroids, and other debris to rain in on the inner Solar System, resulting in a higher rate of impacts with the Earth -- and explaining the odd cyclic nature of mass extinctions.
So I'm not all that surprised about Whitmire's suggestion, although it bears mention that he was talking about the concept in the purely theoretical sense; the weird spectrum of Przybylski's Star was discovered after Whitmire & Wright's paper on the topic.
Curiouser and curiouser.
So we're left with a mystery. The "it's aliens" explanation is hardly going to be accepted by the scientific establishment without a hell of a lot more evidence, and thus far, there is none. The problem is, the peculiar abundance of heavy elements in this very odd star remains unaccounted for by any science we currently understand. The fact that Kipping (and others) are saying "we can't rule out the alien salting hypothesis" is very, very significant.
I'll end with another quote, this one from eminent biologist J. B. S. Haldane: "The universe is not only queerer than we imagine, it is queerer than we can imagine."
Today I'm going to focus on outer space, because if I don't I'll be forced to deal with events down here on Earth, and it's a little early to start drinking.
The James Webb Space Telescope just posted information on a structure called the Saraswati Supercluster, which at a diameter of 650 million light years and a mass of twenty quadrillion times the mass of the Sun, is one of the largest gravitationally-bound structures known. If you look toward the constellation Pisces, visible in the Northern Hemisphere from August to early January, you're staring right at the Saraswati Supercluster.
Not that you can see it with the naked eye. Its center is about four billion light years away, meaning not only that it's extremely faint, the light from it has taken about a third of the age of the universe to get here, so it's really red-shifted. Here's the rather mind-blowing image the JWST team just posted on their site:
On this diagram, the Sun and Solar System are at the center, and as you move outward the scale increases exponentially, allowing us to visualize -- or at least imagine -- the astonishing vastness of the universe. (Saraswati is just slightly to the left of top center on the diagram.)
The name of the supercluster is from a Sanskrit word meaning "ever-flowing stream with many pools," which is appropriate. It's made of forty-three galaxy clusters -- not galaxies, mind you, but galaxy clusters -- of which the largest, Abell 2631, is thought to be made up of over a thousand galaxies (and something on the order of a hundred trillion stars).
If your mind is not boggling yet, you're made of sterner stuff than I am.
Because of its distance and faintness, we haven't known about Saraswati for all that long. It was discovered in 2017 by a team of Indian astronomers led by Joydeep Bagchi from the Inter-University Centre for Astronomy and Astrophysics (IUCAA) in Pune, India, and since has been the object of intense study by astrophysicists for two main reasons. First -- although it's phenomenally massive, its vast diameter makes it remarkable that it hangs together gravitationally. (Remember that gravitational attraction falls off as the square of the distance; it never goes to zero, but it does get really weak.) The fact that it does seem to be acting as a single structure could give us valuable information about the role of the elusive dark matter in making large objects stick together over time.
Second, it might provide some insight into solving another mystery, the question of how (or if) dark energy, the strange force that seems to be making the expansion of the universe speed up, is changing over time. You may recall that just this past August, a pair of papers came out suggesting that the strength of this peculiar phenomenon might be decreasing; that instead of heading toward the rather ghastly prospect of a "Big Rip," where dark energy overpowers every other known force and tears matter apart into a soup of subatomic particles, the expansion might eventually stop or even reverse. The old "oscillating universe" idea, that the universe goes through an endless series of expansions and collapses -- popularized by such brilliant luminaries of physics as Paul Steinhardt and Roger Penrose -- might have legs after all. Studying Saraswati might give us more information about how the strength of dark energy has changed in the four-billion-odd years it's taken the light from the supercluster to arrive here.
So next time you look up into a clear night sky, think of what lies beyond the bit you can actually see. Every individual star visible to the naked eye lives in a (relatively) tiny sphere in the Orion Arm of the Milky Way. The few bits that visible but are farther away -- the smear of light that is all we can discern of the rest of our own galaxy, as well as the few other galaxies we can see without a telescope (like Andromeda and the two Magellanic Clouds) are so distant that individual stars can't be resolved without magnification. What we think of as the impressive grandeur of the night sky is, basically, like thinking you're a world traveler because you drove around your own neighborhood once or twice.
But I guess I need to come back down to Earth. Unfortunately. On the whole, I'm much happier looking up. It makes the current horror show we're living through at least seem a little less overwhelming, and puts our own place in the universe into perspective.
Maybe if our so-called leaders spent more time stargazing, it might provide them with some much-needed humility.
Okay, can we all please please puhleeeeeez stop posting stuff without checking to see if it's true?
I know it's a pain in the ass, but this needs to become a habit. For all of us. Unless you make a practice of never reposting anything anywhere -- which eliminates most people -- it's got to become an automatic reflex when you're using social media. Stop before you hit "forward" or "share" or whatnot and take five minutes to verify that it's accurate.
The reason this comes up is something about comet 3I-ATLAS that I've now seen posted four times. I wrote about 3I-ATLAS here only a couple of weeks ago, and to cut to the chase: the considered opinions of the astronomers who have studied it -- i.e., the people who actually know what the hell they're talking about -- are that the object is an interstellar comet made mostly of frozen carbon dioxide. Despite the claims of people like Avi Loeb, the alien-happy Harvard astronomer, it shows no sign of being an extraterrestrial spacecraft.
That, of course, isn't sufficient for a lot of people. Without further ado, here's the image I've seen repeatedly posted:
There is nothing in this image that is accurate, unless you're counting "3I-ATLAS is an interstellar object" and "Japan has a space agency" as being in the "correct" column. Japan's space agency has released no such "footage." There are no "precise pulsating lights." No scientist -- again, with the exception of Loeb and his pals -- are "questioning if it's artificial."
And the object in the image? That's not 3I-ATLAS. Jack Gilbert, of the Scripps Institute of Oceanography, has identified it as a microorganism. "That is a paramecium," Gilbert writes. "Freshwater I believe -- although better phase contrast, and where it was found, would be ideal for better identification."
Another image that is making the rounds is from NASA, but it's being used to claim that the 3I-ATLAS has changed direction and speed in a fashion that "indicates some kind of propulsion system." This shift in trajectory, they say, made the telescope at NOIRLab (National Optical-Infrared Astronomy Research Laboratory) image alter its aim to keep up with it, resulting in the background stars showing rainbow-colored streaks:
This isn't correct, either. If you go to NOIRLab's website, you find a perfectly reasonable explanation of the streaks right there, without any reference to propulsion systems and alien spacecraft. I quote:
Comet 3I/ATLAS streaks across a dense star field in this image captured by the Gemini Multi-Object Spectrograph (GMOS) on Gemini South at Cerro Pachón in Chile, one half of the International Gemini Observatory, partly funded by the U.S. National Science Foundation (NSF) and operated by NSF NOIRLab. This image is composed of exposures taken through four filters -- red, green, blue and ultraviolet. As exposures are taken, the comet remains fixed in the center of the telescope's field of view. However, the positions of the background stars change relative to the comet, causing them to appear as colorful streaks in the final image.
Once again, the upshot: 3I-ATLAS is a comet. That's all. Of great interest to planetary astronomers, but likely to be forgotten by just about everyone else after March of next year, at which point it will be zooming past Jupiter and heading back out into the depths of space, never to be seen again. There is no credible evidence it's a spaceship. If there was, believe me, you would not be able to get the astronomers to shut up about it. The concept some people have of scientists keeping stuff hidden because they're just that secretive, and don't want anyone to know about their big discoveries, only indicates to me that these people know exactly zero scientists. Trust me on this. I know some actual scientists, and every single one of them loves nothing better than telling you at length about what they're working on, even if it's something that would interest 0.00000001% of the humans who have ever lived, such as the mating habits of trench-dwelling tube worms. If there was strong (or, honestly, any) observation that supported this thing being the ship from Rendezvous With Rama, we'd all know about it.
And after all, if there was evidence out there, the hoaxers wouldn't have to use a photograph of a paramecium to support their bogus claims.
So for fuck's sake, please be careful about what you post. It took me (literally) thirty seconds to find a site debunking the "Japan space agency" thing. What I'm asking you to do is usually not in any way onerous.
I mean, really; wouldn't you rather be posting things that are cool, and also true? There is so much real science to be fascinated and astonished by, you don't need these crazy claims.
And believe me, neither does the internet as a whole.
A loyal reader of Skeptophilia sent me an email asking me what my opinion was about two current candidates for evidence of alien spacecraft -- the Palomar transients and the object called 3I-ATLAS.
First, some facts.
The Palomar transients are some mysterious moving objects spotted on photographic plates taken at Palomar Observatory in the 1940s and 1950s, all before the launch of Sputnik 1, the first artificial satellite, in 1957. They included both single objects and multiple objects -- in one case, five -- arrayed in a straight line. In-depth analysis ruled out conventional explanations like meteors and flaws in the photographic plates; and curiously, there was a forty-five percent higher likelihood of transient detection within one day of nuclear testing, which was going on pretty regularly at the time. The transients also were a little over eight percent more likely on days when there were UAP reports from other sources -- either visual observation by pilots or on-ground observers, or unexplained blips on military radar. The authors of the paper, which appeared in Nature last week, were up front that the phenomenon was "not easily accounted for by prosaic explanations."
One of the Palomar transients, from July 1952 [Image courtesy of Stephen Bruel and Beatriz Villarroel, Nature, 20 October 2025]
3I-ATLAS is an interstellar object -- that's what the "I" stands for. (The ATLAS part is because it was discovered by the Asteroid Terrestrial-impact Last Alert System; but fear not, the closest it will get to Earth is 1.8 astronomical units, so it poses no impact threat.) We know it's an unbound interstellar object because of its speed and trajectory. It's on a hyperbolic path, having come from somewhere in deep space, falling into the gravity well of the Sun, where it will ultimately slingshot its way back out of the Solar System and into deep space once again. From analyses of the object itself, as well as the gas and dust it is currently ejecting, it appears to be an icy comet something on the order of three kilometers across, and mostly composed of frozen carbon dioxide, with small amounts of water ice, carbon monoxide, and carbonyl sulfide.
Comet 3I-ATLAS [Image licensed under the Creative Commons International Gemini Observatory/NOIRLab/NSF/AURA/Shadow the Scientist, 3I-ATLAS noirlab2525b crop, CC BY 4.0]
3I-ATLAS was immediately grabbed by (now rather notorious) astronomer Avi Loeb, whose unfortunate habit of shouting "IT'S ALIENS!" every time something unexplained happens has brought up repeated comparisons to The Boy Who Cried Wolf. Not long after 3I-ATLAS was confirmed to be an interstellar object, Loeb and a couple of collaborators published a paper on arXiv in which they said its "anomalous characteristics" indicate it's an extraterrestrial spacecraft, and might in fact be hostile. The claim was equally quickly shot down by a large number of exasperated astrophysicists who are sick unto death of Loeb's antics. One, Samantha Lawler, said, "while it is important to remain open-minded about any 'testable prediction', the new paper [by Loeb et al.] pushes this sentiment to the limit... [E]xtraordinary claims require extraordinary evidence, but unfortunately, the evidence presented is absolutely not extraordinary."
What strikes me here -- especially with regards to the (many) folks who have weighed in on the possibility that these are evidence of extraterrestrial intelligence -- is the need for a rush to judgment. (Nota bene: this is in no way meant as a criticism of the reader who contacted me with the question; she was just interested in my take both on the facts of the case, and people's reactions to them.) In the case of 3I-ATLAS, I think the evidence very strongly suggests that what we have here is simply a large comet of interstellar origin, so something of great interest to astronomers and astrophysicists, but unlikely otherwise to be earthshattering in any sense including the literal one. As far as the Palomar transients go -- well, we don't know. The most recent of them occurred seventy-odd years ago, and all we have is some old photographic plates to go by. They're certainly curious, and I'm glad they're being looked at, but... that's about all we can say for the time being.
"Well, what about the Menzel Gap?" I've seen asked multiple times. Isn't that suggestive? The "Menzel Gap" refers to the fifteen-year block of missing plates attributable to actions by Harvard Observatory astronomer Donald Howard Menzel, a prominent scoffer about aliens and UFOs, who became notorious for ordering the destruction of hundreds, possibly thousands, of astronomical photographic plates stored there. Menzel cited considerations of storage space, claiming we'd already learned as much from them as we could, but UFO aficionados hint at something darker. Menzel had top secret security clearance, they say; he led a "clandestine life as an elite member of the U. S. intelligence community" and was systematically covering up evidence of aliens visiting the Earth in the fashion of Cigarette-Smoking Man on The X Files.
Why he and others would go to all that trouble to stop the public from finding out about aliens is never really explained. "They were just that evil" is about the clearest it gets, often along with vague claims that it was to prevent panic amongst the populace.
As if what the government was openly doing at the time, and that made headlines worldwide, wasn't equally bad.
In any case, back to the original question: what do I think about all this?
Well, the truth is, I don't think anything. I simply don't know. It seems likely that whatever the Palomar transients were, they were not all due to the same cause; it could be that some were debris from nuclear testing, but that clearly doesn't account for all of them. Menzel might have been a misguided bureaucrat, or might have been destroying the plates to prevent their being co-opted by the UFOs-and-aliens crowd, or may have had some other motives entirely. In any case, it's okay to say "we don't know," and then just leave it there. Perhaps researchers will find more evidence, perhaps not; in either case, the best thing is to hold the question in abeyance, indefinitely if need be.
So that's where we have to leave it. I know that's disappointing; believe me, I've been waiting since I was a six-year-old breathlessly watching Lost in Space for unequivocal evidence of aliens. At the moment, what we've got simply doesn't amount to much. But if you're as intrigued by the possibilities as I am, I have two suggestions.
First, learn some actual astronomy and astrophysics. You're less likely to fall for specious claims if you have a good command of the facts and current scientific models.
Second, keep looking up. As has been commented many times, "It's never aliens... until it is." I still think it's likely that life is common in the universe, and although the distances and scale (and the Einsteinian Cosmic Speed Limit) make it unlikely they've come here, it's not impossible. Maybe there have been extraterrestrial spacecraft passing by, or even landing on, our planet.
Wouldn't it be fun if you were the first to know? Make sure and take lots of pictures, okay?
I was an undergraduate when the original Cosmos first aired.
It was back in 1980, and I still remember being blown away by it all -- the melding of science with animation and gorgeous music, and Carl Sagan's lyrical, almost poetic way of expressing his enduring love for astronomy. My friends and I always waited excitedly for the next episode to air, and the day afterward spent an inordinate amount of time chatting about what we'd learned.
One of the episodes that resonated the most strongly with me was entitled "Encyclopedia Galactica." Sagan predicted a day when we'd know so much about the universe that we'd have an encyclopedia of alien planets, each page of which would be accompanied by a list of their physical characteristics -- and types of life forms. He was unequivocal in his belief that we were not alone in the universe, and that in fact life would turn out to be common. Not, perhaps, "life as we know it, Jim" -- and much of it almost certainly pre-technological -- but life, he thought, would turn out to be pretty much everywhere we looked.
In the forty-five years since it aired, our detecting equipment has gotten better and better, but we're still up against the Fermi Paradox -- that famous quip from physicist Enrico Fermi who, when told that life was likely to be common in the universe, said, "Then where is everybody?" Long-time readers of Skeptophilia may recall that a few years ago I did a deeper dive into the Fermi Paradox and the infamous "three f's," but the fact remains that despite getting better and better at astronomy and astrophysics, we still have no incontrovertible evidence of extraterrestrial life (intelligent or otherwise).
But extrasolar planets? Those are kind of a dime a dozen. As of this month, there have been a bit over six thousand exoplanets conclusively identified, and some of them have challenged our models of what planets can be. (I took a look at a few of the weirder ones in a post earlier this year.) So even if we don't yet have aliens in our back yard, there's been a lot of really cool information discovered -- three examples of which have just come out in the past couple of weeks.
No Andorians yet, more's the pity.
The first is about the TRAPPIST-1 system, which was one of the first multi-planet systems discovered. Not only that, it has four planets in the "Goldilocks zone" -- the region around the host star that is "just right" for having temperatures where water could be in its liquid state. (This doesn't mean there is water; just that if other factors were favorable, there could be liquid water.) Not only that, but we lucked out that TRAPPIST-1 is fairly close (a little over forty light years away, in the constellation of Aquarius), and that its planets' orbits are aligned so that from our perspective, they cross in front of their host star, allowing astrophysicists to use the transits to take a stab at the composition of their atmospheres.
The outstanding YouTuber Dr. Becky Smethurst did a wonderful video explaining how this all works (and why the planet TRAPPIST-1d probably doesn't have an atmosphere), but a capsule summary is that when the planet passes in front of the star, its light passes through the planet's atmosphere (if it has one), and any gases present absorb and scatter characteristic frequencies of light. Compared to the unobstructed spectrum of the star, those frequencies are then missing (or at least diminished in intensity), and from that information astrophysicists can deduce what might be present in the atmosphere.
Well, the other three planets in the habitable zone -- TRAPPIST-1b, c, and d -- have pretty conclusively been shown to lack an atmosphere. So it all hinges on 1e, the farthest one out, and a study at the University of Bristol, using data from the James Webb Space Telescope, has said that it cannot rule out the presence of an atmosphere on that one. Not a ringing endorsement, that, but at least not a categorical no -- so we'll keep our eyes on TRAPPIST-1e and hope future studies will give us good news.
The other two stories are about "rogue exoplanets" -- planets out there floating in space that don't (or at least, don't now) orbit a star. Whether they formed that way, or started out in a stellar system and then were ejected gravitationally, is unknown (and may well be different in different cases). These, for obvious reasons, are considered poor candidates for life, but they still are pretty amazing -- and the fact that we know about them at all is a tribute to our vastly improved ability to detect objects out there in interstellar space.
The first one, CHA-1107-7626, is currently accreting material like mad -- something not seen before in an exoplanet, rogue or otherwise. It is estimated to be between five and ten times the mass of Jupiter, so on the verge of being a "brown dwarf" -- a superplanet that has sufficient mass and pressure to fuse deuterium but not hydrogen. They emit more energy than they absorb, but don't quite have enough for the nuclear furnace to turn on in a big way.
But if CHA-1107-7626 keeps going the way its going, it may get there. It's hoovering up an estimated Jupiter's worth of material every ten million years or so, which is the largest accretion rate of any planet-sized object ever observed. So what we might be witnessing is the very earliest stages of the formation of a new star.
The final study is about the rogue exoplanet SIMP-0136, which came out of Trinity College Dublin and again uses data from JWST. But this exoplanet is bizarre for two different reasons -- it has vast storms of what amounts to liquid droplets of sand... and it has auroras.
Once again, I'm staggered by the fact that we could detect this from so far away. The temperature of the surface of the planet is around 1,500 C -- hotter than my kiln at full throttle -- and it has three hundred kilometer per hour winds that blow around bits of molten silica. But most peculiar of all, the planet's atmosphere shows the characteristic polar light flashes we see down here as auroras.
What's weirdest about that is that -- at least on Earth -- auroras are caused by solar activity, and this planet isn't orbiting a star. The way they form down here is that the solar wind ionizes gases in the upper atmosphere, and when those ions grab electrons, and the electrons descend back to the ground level, they emit characteristic frequencies of light (the same ones, not coincidentally, that are swiped by gases in the atmospheres of planets during transits). Red for monoatomic oxygen, green for diatomic oxygen, blue for molecular nitrogen, and so on.
What is ionizing the gases on SIMP-0136? Astrophysicists aren't sure. Sandstorms here on Earth can certainly cause static electrical discharges (what we laypeople refer to as "bigass lightning bolts"), so it's possible we're seeing the light emitted from interactions between the molten silica and whatever gases make up the planet's atmosphere. But it's too soon to be sure.
So even if we haven't yet discovered Skithra or Slitheen or Sontarans or whatnot, we're still adding some pretty amazing things to our Encyclopedia Galactica. Carl Sagan, as usual, was prescient. As he put it, "Somewhere, something incredible is waiting to be known."
The difficult thing about any sort of historical research is that sometimes, the evidence you're looking for doesn't even exist.
In my own field of historical linguistics, for example, we're trying to determine what languages are related to each other (creating, as it were, a family tree for languages), figuring out word roots, identifying words borrowed from other languages, and reconstructing the ancestral language -- based only on the languages we now have access to. There are times when there simply isn't enough information available to solve the particular puzzle you're working on.
The further back in time you go, the shakier the ground gets. You'll see in etymological dictionaries claims like "the Proto-Indo-European word for 'settlement' or 'town' was *-weyk," but that's an inference; there aren't many Proto-Indo-Europeans around these days to verify if this is correct. It's not just a guess, though. It was reconstructed from the suffixes -wich and -wick you see in a lot of English place names (Norwich, Warwick), the Latin word vicus (meaning "a village in a rural area"), the Welsh gwig and Cornish guic (which mean approximately the same as the Latin does), the Greek word οἶκος (house), the Sanskrit viś and Old Church Slavonic vĭsĭ (both meaning "settlement"), and so on. Using patterns of sound change, we can take current languages (or at least ones we have written records for) and backpedal to make an inference about what the speakers of PIE four thousand years ago might have said.
Still, it is only an inference, and the inherent unverifiability of it sometimes leaves practitioners of "hard science" scoffing and quoting Wolfgang Pauli, that such claims "aren't even wrong." I think that's unduly harsh (but of course, given that this is basically what my master's thesis was about, it's no surprise I get a little defensive). Even so, I think we have to be careful how hard to push a claim based on slim evidence.
That was my immediate thought when I read an article by Jay Norris, of Western Sydney University, in The Conversation. It was about the mythology associated with my favorite naked-eye astronomical feature -- the Pleiades.
Norris and another astronomer, Barnaby Norris (not sure if they're related, or if it's a coincidence), have authored a paper that appeared in a book in 2022 called Advancing Cultural Astronomy which looks at a strange thing: in cultures all over the world, the Pleiades are associated with a collection of seven individuals. They're the Seven Sisters in Greece, and also in many indigenous Australian cultures, for example. And Norris and Norris realized two things that were very odd; first, that even on a clear night, you can only see six stars with the naked eye, not seven; and in both the Greek and Australian myth, the story involves a "lost sister" -- one of the seven who, for some reason or another, disappeared or is hidden.
So they started looking in other traditions, and found that all over the world, in cultures as unrelated as Indonesian, many Native American groups, many African cultures, the Scandinavians, and the Celts, there was the same tradition of associating the Pleiades with the number seven, and with one of the group who was lost.
They then went to the astronomical data. They found that the stars in the Pleiades are moving relative to each other, and that a hundred thousand years ago there would have been seven stars visible to the naked eye in the cluster, but in the interim two of them moved so close together (from our perspective, at least) that they appear to be a single star unless you have a telescope. That, they say, is the "lost sister," and is why cultures all over the world have a tradition that the group used to have seven members, but now only has six.
And this, they said, was evidence that the myth of the Pleiades is one of the oldest stories humans have told. At least fifty thousand years old -- when the indigenous Australians migrated across a grassy valley that (when the sea level rose) became the Bay of Carpentaria -- and perhaps as much as a hundred thousand years old, when the common ancestors of all humans were still living in Africa and (presumably) shared a single cultural tradition.
It's a fascinating claim. I have to admit that the commonalities of the myths surrounding the Pleiades in cultures all over the world are a little hard to explain otherwise. Still, I can't say I'm a hundred percent sold. I know from my work in reconstructive linguistics that chance similarities are weirdly common, and can lead to some seriously specious conclusions. (Long-time readers of Skeptophilia might recall my rather brutal takedown a few years ago of a guy named L. M. Leteane, who used cherry-picked chance similarities between words to support his loony claim that the Pascuanese -- or Easter Islanders -- were originally from Egypt, as were the Olmecs of Central America, and both languages were descended from Bantu.)
So as far as the claim that the story of the Seven Sisters is over fifty thousand years old, count me as interested but unconvinced. I think it's possible; it's certainly intriguing. But to me, it's too hard to eliminate the simpler possibility, that the "loss" of one of the stars in the Pleiades was noted by many ancient cultures -- separately, and much more recently -- and became incorporated into their legends, rather than all the legends of the Pleiades and the lost sister coming from a single, very ancient ancestral story.
But it'll give you something to think about, when you see the Pleiades on the next clear night. Whatever the origins of the myths surrounding it, it's awe-inspiring to think about our distant ancestors looking up at the same beautiful cluster of stars on a chilly, clear winter's night, and wondering what it really was -- same as we're doing today using the tools of science.
"There are more things in Heaven and Earth, Horatio, than are dreamt of in your philosophy."
So wrote William Shakespeare in Hamlet, and if anything, it's a significant understatement. If Shakespeare were writing today, considering recent discoveries in science, he might phrase it as, "Horatio, you seriously have no idea how weird it is out there. I mean, literally," which gains in accuracy but does lose something in poetic diction.
To take just one example, consider the paper that appeared in Astrophysical Journal Letters this week, about a gamma ray burst that was discovered by the amusingly-named Very Large Telescope (they're currently building a bigger one down in Chile which will be called, I shit you not, the Extremely Large Telescope). Gamma ray bursts are already pretty astonishing; NASA describes them as "second only to the Big Bang as the most energetic and luminous phenomena known." There are several possible causes of these enormous releases of high-frequency electromagnetic radiation -- supernovae, the catastrophic merger of neutron stars, and flares from magnetars amongst them. (You would not want to be looking down the gun barrel of one of these when it went off. There is some suspicion that the Late Ordovician Mass Extinction -- one of the "Big Five" mass extinctions, and second only to the Permian-Triassic "Great Dying" event in terms of magnitude -- was caused by a nearby gamma ray burst.)
Most of these events are one-offs, and considering the energy they involve (most of them release more energy in a few seconds than the Sun will in its entire lifetime) you can understand why. After one flare-up of that size, it's unsurprising that it wouldn't do it again any time soon. So the astrophysicists were puzzled when they found a gamma-ray burster (GRB 250702B) that seems to recur -- it produced a sequence of five flares, and did that entire sequence three times. Weirdest still, each time, the interval between the second and third flare in the sequence was an integer multiple of the interval between the first two!
What in the hell could cause that?
The gamma-ray burst seems to be extragalactic -- to be coming from a source outside the Milky Way. The source is near a known galaxy, but whether the burst is coming from within the galaxy, or simply from a source that happens to be lined up with it, hasn't been determined yet. The galaxy is one of the thousands that have been located by the Hubble and James Webb Space Telescopes but have yet to be studied; they don't even know what its red shift is (which would tell you how far away it is). But because the red shift of gamma ray bursts is impossible to determine -- to calculate red shift, you need identifiable spectral lines, and those don't occur in something as massive and chaotic as a burst -- this still wouldn't tell you whether the source was actually inside the galaxy or not.
In fact, there's more that's unknown than known about this phenomena. The periodicity led the researchers to suggest one possibility, that it was some unfortunate massive star in an elliptical orbit around a massive black hole, and having pieces torn off it every time it gets to perihelion. Another possibility is an "atypical stellar core collapse," which is astrophysics-speak for "a collapsing star where we really have no idea why it's acting like it does." A third is that the detected periodicity is an artifact caused by "dust echoes" -- reflection of the original gamma-ray burst from concentric shells of dust surrounding the remains of an exploded star. The final possibility -- at least of the ones the authors came up with -- is that it's an example of gravitational lensing, where light emitted by a star (or other astronomical object) travels close to a black hole, the curved space around the black hole causes the light beam to split along more than one path, and different parts of it arrive at different times.
The paths of light traveling through a gravitational lens [Image is in the Public Domain courtesy of NASA/JPL]
The upshot is that we simply don't know what's going on here. The authors write:
We have... new, multiwavelength observations of a superlative series of associated GRB triggers, GRB 250702B. Our observations reveal a rapidly fading, multiwavelength counterpart likely to be embedded in a galaxy with a complex and asymmetric morphology. We... conclude that GRB 250702B is an extragalactic event. The relatively bright and extended host suggest the redshift is moderate (z < 1).
GRB 250702B is observationally unprecedented in its timescale, morphology, and the onset of X-ray photons prior to the initial GRB trigger. In addition, we find a striking, near-integer time step between the GRB outbursts, suggesting (although not proving) possible periodicity in the events.
All of this is absolutely fascinating to the astronomers, because it opens up the perennial question of "Is this a phenomenon we've already seen and know how to explain, or is it actually new physics?" At present, there's no way to answer this with any certainty. All that's known is something really weird is going on out there, and we're going to have to do a lot more observation before we'll be able to figure out what the explanation is.
So like I said, Shakespeare was spot-on. And the more we look out into the skies, the more we find that is Not Dreamt Of In Our Philosophy. Only now we have astrophysicists working on actually explaining these phenomena -- so perhaps this very peculiar flash-in-the-pan won't remain a mystery forever.
Carl Sagan once said, "Somewhere, something incredible is waiting to be known."
I think that's one of the main things that attracted me to science as a child; its capacity to astonish. I still remember reading the kids' books on various scientific stuff and being astounded to find out things like:
dinosaurs, far from being the "failed experiment" they're often characterized as, "ruled the Earth" (as it were) for about five hundred times longer than humans have even existed. (I only much later found out that dinosaurs still exist; we call 'em birds.)
when supergiant stars end their lives, they detonate in a colossal explosion called a supernova that gives off in a few seconds as much energy as the Sun will emit in its entire lifetime. What's left is called a black hole, where the gravitational pull is so powerful even light can't escape.
bats can hear in a frequency range far above humans, and are so sensitive to their own vocalizations that they can hear the echoes of their own voices and distinguish them from the cacophony their friends and relatives are making.
when an object moves, its vertical and horizontal velocities are completely independent of each other. If you shoot a gun horizontally on a level surface, and simultaneously drop a bullet from the gun's muzzle height, the shot bullet and the dropped bullet will hit the ground at the same time.
And that's all stuff we've known for years, because (not to put too fine a point on it) I'm so old that when I was a kid, the Dead Sea was just sick. In the intervening fifty years since I found out all of the above (and lots of other similar tidbits) the scientists have discovered tons of new, and equally amazing, information about our universe and how it works. We've even found out that some of what we thought we understood was wrong, or at least incomplete; a good example is photoperiodism, the ability of flowering plants to keep track of day length and thus flower at the right time of year. It was initially thought that they had a system that worked a bit like a chemical teeter-totter. A protein called phytochrome has a "dark form" and a "light form" -- the dark form changes to the light form during the day, and the reverse happens at night, so the relative amounts of the two might allow plants to keep track of day length. But it turns out that all it takes is a flash of red light in the middle of the night to completely upend the plant's biological clock -- so whatever is going on is more complex that we'd understood.
This sudden sense of "wow, we don't know as much as we thought!", far from being upsetting, is positively thrilling to scientists. Scientists are some of the only people in the world who love saying, "I don't understand." Mostly because they always follow it up with "... yet." Take, for example, the discovery announced this week by the National Radio Astronomy Observatory of a huge cloud of gas and dust in our own Milky Way Galaxy that prior to this we hadn't even known was there.
It's been named the Midpoint Cloud, and it's about two hundred light years across. It's an enormous whirlpool centered on Sagittarius A*, the supermassive black hole at the galaxy's center, and seems to act like a giant funnel drawing material inward toward the accretion disk.
"One of the big discoveries of the paper was the giant molecular cloud," said Natalie Butterfield, lead author of the paper on the phenomenon, which appeared this week in The Astrophysical Journal. "No one had any idea this cloud existed until we looked at this location in the sky and found the dense gas. Through measurements of the size, mass, and density, we confirmed this was a giant molecular cloud. These dust lanes are like hidden rivers of gas and dust that are carrying material into the center of our galaxy. The Midpoint Cloud is a place where material from the galaxy's disk is transitioning into the more extreme environment of the galactic center and provides a unique opportunity to study the initial gas conditions before accumulating in the center of our galaxy."
[Image credit: NSF/AUI/NSF NRAO/P.Vosteen]
Among the amazing features of this discovery is that it contains a maser -- an intense, focused microwave source, in this case thought to be caused by compression and turbulence in the ammonia-rich gas of the cloud. Additionally, there are several sites that seem to be undergoing collapse; we might be witnessing the birth of new stars.
What's astonishing to me is that this cloud is (1) humongous, (2) in our own galaxy, and (3) glowing like crazy in the microwave region of the spectrum, yet no one had any idea it was there until now. How much more are we overlooking because we haven't tuned into the right frequency or turned our telescopes to the right coordinates?
The universe is a big place. And, I suspect, it's absolutely full of surprises. Hell, there are enough surprises lying in wait right here on the Earth; to give just one example, I've heard it said that we know more about the near side of the Moon than we do about the deep oceans.
How could anyone not find science fascinating?
This is also why I've never understood how people think that science's progress could be turned into a criticism -- I used to hear it from students phrased as, "why do we have to learn all this stuff when it could all be proven wrong tomorrow?" Far from being a downside, science's capacity to update and self-correct is its most powerful strength. How is it somehow better to cling to your previous understanding in the face of evidence to the contrary?
That, I don't think I'll ever come close to comprehending.
I'll end with another quote from a scientific luminary -- the brilliant physicist Richard Feynman -- that I think sums it all up succinctly: "I'd much rather questions that cannot be answered than answers that cannot be questioned."
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