Flash in the pan

"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.

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The lure of the unknown

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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Requiem for a dead planet

If I had to pick my favorite episode of Star Trek: The Next Generation, the clear winner would be "The Inner Light."  Some classic episodes like "Darmok," "Frames of Mind," "Yesterday's Enterprise," "The Offspring," "Cause and Effect," "Remember Me," "Time's Arrow," "The Chase," and "Best of Both Worlds" would be some stiff competition, but "The Inner Light" not only has a beautiful story, but a deep, heartwrenching bittersweetness, made even more poignant by a tour-de-force performance by Patrick Stewart as Captain Jean-Luc Picard.

If you've not seen it, the plot revolves around the Enterprise encountering a huge space station of some kind, of apparent antiquity, and in the course of examining it, it zaps Captain Picard and renders him unconscious.  What his crew doesn't know is that it's dropped him into a dream where he's not a spaceship captain but an ordinary guy named Kamin, who has a wife and children and a job as a scientist trying to figure out what to do about the effect of his planet's sun, which has increased in intensity and is threatening devastating drought and famine.

As Kamin, he lives for forty years, watching his children grow up, living through the grief of his wife's death and the death of a dear friend, and ultimately grows old without ever finding a solution to his planet's dire circumstances.  All the while, the real Captain Picard is being subjected to ongoing interventions by Dr. Crusher to determine what's keeping him unconscious, and ultimately unsuccessful attempts to bring him out of it.  In the end, which makes me ugly cry every damn time I watch it, Kamin lives to watch the launch of an archive of his race's combined knowledge, realizing that the sun's increase in intensity is leading up to a nova that will destroy the planet, and that their civilization is doomed.  It is, in fact, the same archive that the Enterprise happened upon, and which captured Picard's consciousness, so that someone at least would understand what the civilization was like before it was wiped out tens of thousands of years earlier.

"Live now," Kamin says to his daughter, Maribol.  "Make now always the most precious time.  Now will never come again."

And with that, Picard awakens, to find he has accumulated four decades of memories in the space of about a half-hour, an experience that leaves a permanent mark not only on his mind, but his heart.

*brief pause to stop bawling into my handkerchief*

I was immediately reminded of "The Inner Light" by a paper I stumbled across in Nature Astronomy, called, "Alkali Metals in White Dwarf Atmospheres as Tracers of Ancient Planetary Crusts."  This study, led by astrophysicist Mark Hollands of the University of Warwick, did spectroscopic analysis of the light from four white dwarf stars, which are the remnants of stellar cores left behind when Sun-like stars go nova as their hydrogen fuel runs out at the end of their lives.  In the process, they vaporize any planets that were in orbit around them, and the dust and debris from those planets accretes into the white dwarf's atmosphere, where it's detectable by its specific spectral lines.

In other words: the four white dwarfs in the study had rocky, Earth-like planets at some point in their past.

"In one case, we are looking at planet formation around a star that was formed in the Galactic halo, 11-12.5 billion years ago, hence it must be one of the oldest planetary systems known so far," said study co-author Pier-Emmanuel Tremblay, in an interview in Science Daily.  "Another of these systems formed around a short-lived star that was initially more than four times the mass of the Sun, a record-breaking discovery delivering important constraints on how fast planets can form around their host stars."

This brings up a few considerations, one of which has to do with the number of Earth-like planets out there.  (Nota bene: by "Earth-like" I'm not referring to temperature and surface conditions, but simply that they're relatively small, with a rocky crust and a metallic core.  Whether they have Earth-like conditions is another consideration entirely, which has to do with the host star's intrinsic luminosity and the distance at which the planet revolves around it.)  In the famous Drake equation, which is a way to come up with an estimate of the number of intelligent civilizations in the universe, one of the big unknowns until recently was how many stars hosted Earth-like planets; in the last fifteen years, we've come to understand that the answer seems to be "most of them."  Planets are the rule, not the exception, and as we've become better and better at detecting exoplanets, we find them pretty much everywhere we look.

When I read the Hollands et al. paper, I immediately began wondering what the planets around the white dwarfs had been like before they got flash-fried as their suns went nova.  Did they harbor life?  It's possible, although considering that these started out as larger stars than our Sun, they had shorter lives and therefore less time for life to form, much less to develop into a complex and intelligent civilization.  And, of course, at this point there's no way to tell.  Any living thing on one of those planets is long since vaporized along with most of the planet it resided on, lost forever to the ongoing evolution of the cosmos.

If that's not gloomy enough, it bears mention that this is the Earth's ultimate fate, as well.  It's not anything to worry about (not that worry would help in any case) -- this eventuality is billions of years in the future.  But once the Sun exhausts its supply of hydrogen, it will balloon out into a red giant, engulfing the inner three planets and possibly Mars as well, then blow off its outer atmosphere (that explosion is the "nova" part), leaving its exposed core as a white dwarf, slowly cooling as it radiates its heat out into space.

Whether by that time we'll have decided to send our collective knowledge out into space as an interstellar archive, I don't know.  In a way, we already have, albeit on a smaller scale than Kamin's people did; Voyager 2 carries the famous "golden record" that contains information about humanity, our scientific knowledge, and recordings of human voices, languages, and music, there to be decoded by any technological civilization that stumbles upon it.  (It's a little mind-boggling to realize that in the 48 years since Voyager 2 was launched, it has traveled about 20,000,000,000 kilometers, so is well outside the perimeter of the Solar System; and that sounds impressive until you realize that's only 16.6 light hours away, and the nearest star is 4.3 light years from us.)

So anyhow, those are my elegiac thoughts on this August morning.  Dead planets, dying stars, and the remnants of lost civilizations.  Sorry to be a downer. If all this makes you feel low, watch "The Inner Light" and have yourself a good cry.  It'll make you feel better.

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The phantom whirlpool

The universe is a dangerous place.

I'm not talking about crazy stuff happening down here on Earth, although a lot of that certainly qualifies.  The violence we wreak upon each other (and by our careless actions, often upon ourselves) fades into insignificance by comparison to the purely natural violence out there in the cosmos.  Familiar phenomena like black holes and supernovas come near the top of the list, but there are others equally scary whose names are hardly common topics of conversation -- Wolf-Rayet stars, gamma-ray bursters, quasars, and Thorne-Zytkow objects come to mind, not to mention the truly terrifying possibility of a "false vacuum collapse" that I wrote about here at Skeptophilia a while back.

It's why I always find it odd when people talk about the how peaceful the night sky is, or that the glory of the cosmos supports the existence of a benevolent deity.  Impressive?  Sure.  Awe-inspiring?  Definitely.

Benevolent?  Hardly.  The suggestion that the universe was created to be the perfectly hospitable home to humanity -- the "fine-tuning" argument, or "strong anthropic principle" -- conveniently ignores the fact that the vast majority of the universe is intrinsically deadly to terrestrial life forms, and even here on Earth, we're able to survive the conditions of less than a quarter of its surface area.

I'm not trying to scare anyone, here.  But I do think it's a good idea to keep in mind how small and fragile we are.  Especially if it makes us more cognizant of taking care of the congenial planet we're on.

In any case, back to astronomical phenomena that are big and scary and can kill you.  Even the ones we know about don't exhaust the catalog of violent space stuff.  Take, for example, the (thus far) unexplained invisible vortex that is tearing apart the Hyades.

The Hyades is a star cluster in the constellation Taurus, which gets its name from the five sisters of Hyas, a beautiful Greek youth who died tragically.  Which brings up the question of whether any beautiful Greek youths actually survived to adulthood.  When ancient Greeks had kids, if they had a really handsome son, did they look at him and shake their heads sadly, and say, "Well, I guess he's fucked"?

To read Greek mythology, you get the impression that the major cause of death in ancient Greek was being so beautiful it pissed the gods off.

Anyhow, Hyas's five sisters were so devastated by the loss of their beloved brother that they couldn't stop crying, so the gods took pity on them even though Zeus et al. were the ones who caused the whole problem in the first place, and turned them into stars.  Which I suppose is better than nothing.  But even so, the sisters' weeping wouldn't stop -- which is why the appearance of the Hyades in the sky in the spring is associated with the rainy season. (In fact, in England the cluster is called "the April rainers.")

The Hyades [Image licensed under the Creative Commons NASA, ESA, and STScI, Hyades cluster, CC BY-SA 4.0]

In reality, the Hyades have nothing to do with rain or tragically beautiful Greek youths.  They are a group of fairly young stars, on the order of 625 million years old (the Sun is about ten times older), and like most clusters was created from a collapsing clump of gas.  The Hyades are quite close to us -- 153 light years away -- and because of that have been intensively studied.  Like many clusters, the tidal forces generated by the relative motion of the stars is gradually pulling them away from each other, but here there seems to be something else, something far more violent, going on.

A press release from the European Space Agency describes a study of the motion of the stars in the Hyades indicating that their movements aren't the ordinary gentle dissipation most clusters undergo.  A team led by astrophysicist Tereza Jerabkova used data from the European Southern Observatory to map members of the cluster, and to identify other stars that once were part of the Hyades but since have been pulled away, and they found that the leading "tidal tail" -- the streamer of stars out ahead of the motion of the cluster as a whole -- has been ripped to shreds.

The only solution Jerabkova and her team found that made sense of the data is that the leading tail of the Hyades collided -- or is in the process of colliding -- with a huge blob of some sort, containing a mass ten million times that of the Sun.  The problem is, an object that big, only 153 light years away, should be visible, or at least detectable, and there seems to be nothing there.

"There must have been a close interaction with this really massive clump, and the Hyades just got smashed," Jerabkova said.

So what is this "really massive clump" made of?  Given the absence of anything made of ordinary matter that is anywhere nearby, the team suggests that it might be something more exotic -- a "dark matter sub-halo."  These hypothesized objects could be scattered across the universe, and might provide the energetic kick to objects whose trajectories can't be explained any other way. But what exactly they are other than a bizarre phantom gravitational whirlpool, no one knows.

Nor what the risk is if we're close to one.

So add "dark matter sub-halos" to our list of scary astronomical phenomena.  I find the whole thing fascinating, and a little humbling.  I'll still find the beauty of a clear night sky soothing, but that's only if I can get my scientific mind to shut the hell up long enough to enjoy it.  Because the truth is, a lot of those twinkling lights are anything but peaceful.

But I suppose it's still better than the gods killing you if you're too handsome.  That would just suck, not that I personally am in any danger.

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Awe

I was pondering the question of what the hell is wrong with so many of the people in positions of power on our planet, and I've come to the conclusion that part of it is that they've lost the capacity to feel awestruck.

When we're awestruck, in a way, our entire world gets turned on its head.  The day-to-day concerns that take up most of our mental and emotional space -- jobs, relationships, paying the bills, keeping up with household chores, the inevitable aches and pains -- suddenly are drowned by a sense that in the grand scheme of things, we are extremely small.  It's not (or shouldn't be) a painful experience.  It's more that we are suddenly aware that our little cares are just that: little.  We live in a grand, beautiful, mysterious, dazzling universe, and at the moments when we are privileged to perceive that, our senses are swept away.

The philosophers have come up with a name for such experiences: numinous.  It doesn't imply a connection to a higher power (although it manifests that way, or is interpreted that way, for some people).  German writer Rudolf Otto describes such a state as "a non-rational, non-sensory experience or feeling whose primary and immediate object is outside the self...  This mental state presents itself as wholly other, a condition absolutely sui generis and incomparable, whereby the human being finds himself utterly abashed."

What would happen if you couldn't -- or were afraid to -- experience awe?  This would trap you in the petty quotidian trivia of life, and very likely magnify their importance in your mind, giving them far more gravitas than they deserve.  I suspect it could also magnify your own self-importance.

It'd be interesting to see if there's an inverse correlation between narcissism and our capacity to feel awestruck.  After all, how could you simultaneously perceive the glory and grandeur of the universe, and remain convinced that your needs are the most important thing within it?  And if you combine narcissism with amorality, you produce an individual who will never admit fault, never look beyond their own desires, and stop at nothing to fulfill them.

We could probably all name a few prominent people this describes.

I think the two things that have the greatest ability to make me feel awe are music and astronomy.  Music has had the ability to pick me up by the emotions and swing me around since I was very small; my mom used to tell the story of my being about four and begging her to let me use the record player.  She finally relented (one of the few times she ever did) and showed me how, and -- to my credit -- I never damaged a single record.  They were simply too important to me.

Just a couple of days ago, I was in the car, and Ralph Vaughan Williams's Fantasia on a Theme by Thomas Tallis came on the classical station I was listening to.  If I had to name one piece that has that ability to lift me out of myself, that's the one I'd pick.  The first time I heard it, as a teenager, I ended up with tears streaming down my face, and honestly had been unaware of where I was for the entire fifteen-minute play time.

It's astronomy, though, that is why this topic comes up today.  A paper this week in the journal Astronomy and Astrophysics describes a new study of the Silver Coin Galaxy in the constellation Sculptor, a beautiful spiral galaxy about 11.4 million light years away.  The study, which required fifty hours of time at the European Southern Observatory in Chile, produced an image with unprecedented detail:

The Silver Coin is called a "starburst galaxy," a region of space undergoing an exceptionally high rate of star formation, so it's of great interest to astronomers and astrophysicists as we learn more about how galaxies, stars, and planetary systems form and evolve.  "Galaxies are incredibly complex systems that we are still struggling to understand," said Enrico Congiu, who led the study.  "The Sculptor Galaxy is in a sweet spot.  It is close enough that we can resolve its internal structure and study its building blocks with incredible detail, but at the same time, big enough that we can still see it as a whole system."

In that one rectangular photograph is captured the light from billions of stars.  From what we know of stars in our own galaxy, it's likely that the majority of those points of light have their own planetary systems.  It's not certain -- but many astronomers think it's very likely -- that a good many of those planets host life.  Some of that life might be intelligent, and looking back at us through their own telescopes, wondering about us as we do about them.

How could anyone look at this image, think those thoughts, and not be awestruck?

To me, that was part of what I wanted as a science teacher.  I honestly couldn't have cared less if my students got to the end of the year and couldn't tell me what the endoplasmic reticulum did.  (If they need to know that at some point in their lives, they can look it up.)  What I do care deeply about is that they know how to think critically, can distinguish truth from fiction, and have enough basic understanding of biology to be able to make good decisions about their health and the environment.  And in addition, I tried to instill in them a sense of wonder at how cool science is.

That I did at least sometimes succeed is supported by a funny incident from not long before I retired.  I was having one of our required twice-yearly administrator observations, and the principal was watching me teach a lesson to my AP Biology class.  I recall that it was something about genetics -- always a favorite subject -- but I can't remember what exactly the topic was that day.  But something I said made one kid's eyes pop open wide, and he said, "Wow, that is so fucking cool."

Then he had the sudden aghast realization that the principal was sitting in the back of the room.

The kid turns around, red-faced, and said, "Oh, my god, Mr. Koeng, I'm sorry."

The principal grinned and said, "No, that's okay.  You're right.  It is really fucking cool."

I was lucky to work, by and large, for great administrators during my 32-year career, and I often discussed with them my goal as a science teacher of instilling wonder.  But I think we all need to land in that space more often.  The ability to look around us and say, "Wow.  Isn't this amazing?" is incredibly important, and also terribly easy to lose.  The morass of daily concerns we're faced with can add up in our minds to something big enough to block out the stars.

And isn't that sad?

So I'll end with an exhortation: find some time this week to look and listen and experience what's around you.  Get down and examine the petals of a flower.  Go out on a dark, clear night and look up at the stars.  Listen to a piece of music -- just listen, don't engage in the "listening while" that most of us do every day.  Create the space in your life to experience a little awe.

But don't be surprised if you come out of the experience changed.  Being awestruck will do that.

In fact, maybe that's the point.

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Down in flames

The more exoplanets we find, the more they challenge our notion of how planets should be.

For the many of us who grew up watching Star Trek and Lost in Space and Doctor Who, it's understandable that we picture planets around other stars as being pretty much like the ones we have here in our own Solar System -- either small and rocky like the Earth, or gas giants like Jupiter and Saturn.

The truth is, there is a far greater variety of exoplanets than we ever could have dreamed of, and every new one we find holds some sort of surprise.  Some of the odder ones are:

• 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.
• 55 Cancri e, nicknamed the "diamond planet."  Another "hot super-Earth," this one is thought to be carbon rich, and that because of the heat and pressure, much of the carbon could be in the form of diamonds.  (Don't tell Dr. Smith.)
• PSR J1719−1438, a planet orbiting a pulsar (the collapsed, rapidly rotating core of a giant star).  It has one of the fastest rates of revolution of any orbiting object known, circling its host star 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.

We now have a new one to add to the list -- 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 BD+05 4868 Ab is literally evaporating, and leaving a long, comet-like tail in its wake.

The estimate is that each time it orbits, it loses a Mount Everest's worth of rock from its surface.  It's not a large world already, and the researchers say it is on track to disintegrate completely in under two million years.

"The extent of the tail is gargantuan, stretching up to nine million kilometers long, or roughly half of the planet's entire orbit," said Marc Hon of MIT, who co-authored a paper on the planet, which appeared this week in Astrophysical Journal Letters.  "The shape of the transit is typical of a comet with a long tail,.  Except that it's unlikely that this tail contains volatile gases and ice as expected from a real comet -- these would not survive long at such close proximity to the host star.  Mineral grains evaporated from the planetary surface, however, can linger long enough to present such a distinctive tail."

[Image licensed under the Creative Commons Marc Hon et al. 2025, submitted to AAS Journals, BD+05 4868Ab simulation dust cloud (Figure 12), CC BY 4.0]

So we have a new one to add to the weird exoplanet list -- a comet-like planet in the process of going down in flames.  Not a place you'd want to beam your away team to, but fascinating anyhow.

Makes me wonder what the next bizarre find is going to be.  The universe is like that, isn't it?  We think we have it figured out, then it turns around and astonishes us.

I, for one, think that is fantastic.

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Mushballs

I first ran into the concept that not all planets had hard, rocky surfaces -- like Earth, and the ones I was all too familiar with from scientific documentaries like Lost in Space -- when I was about eight.

It was in one of those kids' books about astronomy, and I found the whole thing absolutely fascinating.  Mercury, Venus, Earth, and Mars were small, solid, and made mostly of silicate rocks.  Certainly, the four have their dramatic differences -- airless, scorched Mercury; Venus with its brutally hot, carbon-dioxide-rich atmosphere and clouds of sulfuric acid; temperate, lovely Earth; and chilly, windswept, dusty Mars.  But all four, at least to some extent, fit the picture I'd had of what a planet should look like.

But then the outer four -- Jupiter, Saturn, Uranus, and Neptune -- confounded that completely.

All four are gas giants, massive planets with no solid surface (or, if there is one, it's buried so deep as to be all but inaccessible).  The atmospheres are largely hydrogen, helium, carbon monoxide and dioxide, ammonia, and methane.  They rotate fast -- Jupiter, the largest planet, rotates once on its axis every ten hours -- and this, combined with some serious convection currents, creates enormous storms, the most famous of which is Jupiter's Great Red Spot, which is large enough to swallow the Earth entirely and has wind speeds over four hundred kilometers per hour.

[Image is in the Public Domain courtesy of NASA/JPL]

Even the gas giants' cores aren't like the Earth's; ours is predominantly iron and nickel, while Jupiter -- and, it is surmised, the other three -- have a core largely composed of hydrogen compressed to the point that its electrons delocalize and it begins to act like a metal.  (This metallic hydrogen core is thought to be the source of Jupiter's enormous magnetic field.)

So my picture of the outer four planets was forever changed.  They were huge, churning blobs of gas, not solid at all.  Saturn, in fact, has such a low overall density that if you could find a swimming pool big enough, it'd float.  Then, my mind was further blown when I was twenty and first saw Carl Sagan's Cosmos, where he suggested that such a planet might still host life -- floating or flying creatures that could ride the wild thermal updrafts, and somehow metabolize the anoxic stew of gases they live in.

What's coolest of all, though, is that our understanding of the gas giants is still being refined.  A study out of the University of California - Berkeley found that certain areas of Jupiter's atmosphere are strangely ammonia-depleted.  This is unexpected -- the constant turbulence, you'd think, would result in uniform mixing, just like stirring a cup of coffee distributes the cream and sugar evenly throughout.  If there are areas low in ammonia, what is keeping them that way?

The researchers found a mechanism that might be responsible.  Updrafts in low-pressure zones might, just as they do on Earth, create hailstorms.  But everything's bigger on Jupiter -- bigger than Texas, even -- and these enormous updrafts allow the formation of huge "mushballs" composed primarily of frozen ammonia and water that, once they are too heavy to keep aloft any more, fall down into the lower layers of the atmosphere, leaving upper regions depleted.

So unlike on Earth, where a three-centimeter hailstone is considered pretty huge, these would be between the size of a softball and a basketball.

"The mushball journey essentially starts about fifty to sixty kilometers below the cloud deck as water droplets," said Chris Moeckel, lead author of the paper on the phenomenon, which appeared in Science Advances this week.  "The water droplets get rapidly lofted all the way to the top of the cloud deck, where they freeze out and then fall over a hundred kilometers into the planet, where they start to evaporate and deposit material down there.  And so you have, essentially, this weird system that gets triggered far below the cloud deck, goes all the way to the top of the atmosphere and then sinks deep into the planet...  Imke [de Pater, Moeckel's advisor] and I both were like, 'There's no way in the world this is true.'  So many things have to come together to actually explain this, it seems so exotic.  I basically spent three years trying to prove this wrong.  And I couldn't prove it wrong."

So Sagan's floaters and flyers would not only have to deal with Jupiter's screaming winds and monstrous lightning storms, they'd have to dodge volleyball-sized hailstones.

Not the most hospitable place in the world.

It's pretty cool that even our own Solar System still has the capacity to amaze us.  The more we learn, the more questions we have.  It's like Neil deGrasse Tyson said; "As our knowledge grows, so too does the perimeter of our ignorance."  And sometimes it's a simple, innocuous-seeming question -- like, "why are some parts of Jupiter's atmosphere low in ammonia?" -- that leads to a huge shift in our picture of how some part of the universe works.

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The signature

As much as I love the movie Contact, trying to find extraterrestrial life isn't just a matter of tuning in to the right radio frequency.

There's no guarantee that even intelligent life would use radio waves to communicate, and if they did, that they'd do it in such a way that we could decipher the message.  I must admit, though, that the whole "sequence of prime numbers" thing as a beacon was a pretty cool idea; it's hard to imagine a natural phenomenon that would result in blips in a pattern of prime numbers.

Even besides the issue with how exactly a technological species would choose to communicate, there's the problem that this method would miss the vast majority of life that's potentially out there.  Consider the fact that there's been life on Earth for 3.8 billion years, give or take a day or two, and until about a hundred years ago, we weren't producing any radio waves ourselves.  To a civilization two hundred light years away -- so, seeing us as we were two hundred years ago -- Earth would be, to borrow C. S. Lewis's pithy phrase, a completely silent planet, even though there was a thriving biosphere that included at least one intelligent, soon-to-be-technological species.

So except for those presumably few planets that host intelligent beings who communicate kind of like we do, detecting extraterrestrial life is a tricky question.  The most promising approach has been to look for biosignatures -- chemical traces that (as far as we know) can only be produced by living things.  One example on Earth is the fact that our atmosphere contains both oxygen and methane.  Both are highly reactive (especially with each other); to keep stable levels of these gases in the atmosphere requires that something is continuously producing them, because they're constantly being removed by oxidation/reduction reactions.  In this case, photosynthesis and bacterial methanogenesis, respectively, pump them into the atmosphere as fast as they're being destroyed, so the levels remain relatively stable over time.

Two other chemicals that, on the Earth at least, are entirely biological in origin are dimethyl sulfide and dimethyl disulfide.  You've undoubtedly encountered these before; they're partly responsible for the unpleasant smell when you cook cabbage.  They're produced by a variety of living things, including bacteria, plants, and fungi -- dimethyl sulfide is what truffle-hunting pigs are homing in on when they're after truffles. 

Well, data from the James Webb Space Telescope showed that an exoplanet called K2-18b has measurable quantities of both dimethyl sulfide and dimethyl disulfide -- to the point that even the astronomers, who ordinarily have zero patience with the "It's aliens!" crowd, are saying "this is the strongest hint yet of biological life on another planet."

So far, the spectroscopic data that found the chemicals is at a significance level of "3-sigma" -- meaning there's a 0.3% chance that the signal was a statistical fluke (or, put another way, a 99.7% chance that it's the real deal).  It's exciting, but we've seen 3-sigma data do a faceplant before, so I'm trying to restrain myself.  Generally 5-sigma -- a 0.00006% chance of it being a fluke -- is the standard for busting out the champagne.  But even so, this is pretty amazing.

K2-18b is 124 light years away, and is thought to be a "Hycean world" -- an ocean-covered world with a thick, hydrogen-rich atmosphere.  So whatever life is there is very likely to be marine.  But even if we're not talking about your typical Star Trek-style planet with lots of rocks and an orange sky and aliens that look like humans but with rubber facial appendages, the levels of DMS and DMDS suggest a thriving biosphere.

"Earlier theoretical work had predicted that high levels of sulfur-based gases like DMS and DMDS are possible on Hycean worlds," said Nikku Madhusudhan of Cambridge University, who co-authored the study, which appeared this week in Astrophysical Journal Letters.  "And now we've observed it, in line with what was predicted. Given everything we know about this planet, a Hycean world with an ocean that is teeming with life is the scenario that best fits the data we have."

The issue, of course, is not just the statistical significance; 99.7% seems pretty good to me, even if it doesn't satisfy the scientists.  The problem is that sneaky little phrase that was in my description of biosignatures earlier; "as far as we know."  We don't know of a way to produce DMS and DMDS in significant quantities except by biological processes, but that doesn't mean one doesn't exist.  It could be that in the weird chemical soup on an planet in another star system, there's an abiotic way to produce a stable amount of these two compounds, and we just haven't figured it out yet.

Be that as it may, it's still pretty damn exciting.  It's certainly the closest we've gotten to "there's life out there."  And being only 124 light years away -- in our stellar neighborhood, really -- it's right there for us to study more intensively.  Which the astronomers will definitely be doing.

So that's our cool news for today.  I don't know about you, but now I'm daydreaming about what kind of life there might be on a world entirely covered by water.  I'm sure that whatever they are, they'll be "forms most beautiful and most wonderful" beyond Charles Darwin's wildest dreams.

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Rough neighborhood

Most likely all of you know about Sagittarius A*, the supermassive black hole that sits at the center of the Milky Way Galaxy.

It's hard to talk about it without lapsing into superlatives.  It has a mass about 4.3 million times that of the Sun.  It's event horizon -- the "point of no return," the closest you can get to a black hole without being trapped by its gravitational pull -- has a radius of 11.3 million kilometers.  It sits at the center of a fifteen-light-year-wide whirlpool of gas and dust called the accretion disk, which we know about because the material in it is moving so fast it has heated up to as high as ten million degrees Celsius, resulting in a steady emission of high-frequency x-rays.

[Image licensed under the Creative Commons EHT Collaboration, EHT Sagittarius A black hole, CC BY 4.0]

It's curious that something this luminous wasn't immediately obvious to astronomers.  First, it doesn't emit a lot of visible light; we didn't have telescopes capable of detecting the x-rays that are its fingerprint until 1933.  By the 1970s, more precise observations showed that whatever the x-ray source was, it was extremely compact.  It wasn't until 1994 that Charles H. Townes and Reinhard Genzel showed that its mass and diameter were consistent with its being a black hole.  Another reason it took that long is that between us and the center of the galaxy there are massive dust clouds, so any visible light it does emit (or which is emitted by the dense clouds of glowing gas near it) mostly gets blocked.  (Even so, looking toward the center of the Milky Way in the constellation Sagittarius, visible where I am in late summer, is pretty damn spectacular.)

The third reason that we don't get the full luminosity of whatever electromagnetic radiation is emitted from Sagittarius A* is a fortunate one for us; because of the black hole's immense magnetic field, any bursts of light tend to get funneled away along the axis of its spin, creating jets moving perpendicularly to the galactic plane.  We, luckily, are comfortably out in the stellar suburbs, in one of the Milky Way's spiral arms.  Our central black hole is fairly quiet, for the most part, but even so, looking down the gun barrel of its magnetic field axis would not be a comfortable position to reside.

The reason this comes up is some new research out of the University of Colorado - Boulder, which used data from the James Webb Space Telescope to solve a long-standing question about why, given the high density of hydrogen and helium gas near the galactic center, the rate of star formation there is anomalously low.  This region, called Sagittarius C, extends about two hundred light years from the central black hole (by comparison, the Solar System is twenty-six thousand light years away).  And what the team of researchers found is that threading the entire region are filaments of hot, bright plasma, some of them up to several light years in length.

The reason for both the filaments and the low star formation rate is almost certainly the black hole's magnetic field, which acts to compress any gas that's present along the field lines, heating it up dramatically.  This, in turn, creates an outward pressure that makes the gas resist collapsing and forming stars.

"It's in a part of the galaxy with the highest density of stars and massive, dense clouds of hydrogen, helium and organic molecules," said Samuel Crowe, who co-authored the paper, which appeared this week in The Astrophysical Journal.  "It's one of the closest regions we know of that has extreme conditions similar to those in the young universe...  Because of these magnetic fields, Sagittarius C has a fundamentally different shape, a different look than any other star forming region in the galaxy away from the galactic center."

It is, to put it mildly, a rough neighborhood.

It's staggering how far we've come in our understanding of what our ancestors called the "fixed stars" -- far from being eternal and unchanging, the night sky is a dynamic and ever-evolving place, and with new tools like the JWST we're finding out how much more we still have to learn.  Something to think about the next time you look up on a clear, starry night.  The peaceful, silent flickering, set against the velvet black background, is an illusion; the reality is far wilder -- and far more interesting.

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Ill-starred

I've never believed in luck.  It's true, however, that life is full of caprices.  Although the laws of physics are rigorously enforced in all jurisdictions, the bigger picture often seems to be chaotic.  I think a lot of people put too much stock in superstitious beliefs about good (or bad) luck; I much more tend to agree with Thomas Jefferson, who famously said, "I've found that the harder I work, the more luck I seem to have."

Still, sometimes you read about what some people have gone through, and you can't help coming away with the feeling that the stars must have been misaligned when they were born.  Their lives are just one disaster after another -- and I choose the word deliberately, because disaster comes from Latin words meaning "bad stars," and the specific example I'm thinking of was an eighteenth-century French astronomer who just could not catch a break.

His full name was Guillaume Joseph Hyacinthe Jean-Baptiste Le Gentil de la Galeisière, but historians of science know him as Guillaume Le Gentil.  He was born in September of 1725 in Coutances, and was inspired to study astronomy after hearing a lecture by the famous astronomer, cartographer, and world traveler Joseph-Nicolas Delisle.  After receiving his bachelor's degree in the subject, he threw himself into research with great gusto.  He discovered the Pinwheel Cluster (Messier 36), the Starfish Cluster (Messier 38), and a dark nebula in the constellation Cygnus that is now called Le Gentil 3 in his honor.

The Pinwheel Cluster [Image is in the Public Domain, courtesy of the 2 Micron All-Sky Survey]

Just about everything else he attempted, however, was... a disaster.

In 1760, Russian polymath Mikhail Vasilyevich Lomonsov came up with a method for refining the length of the Astronomical Unit (A.U.), the distance between the Earth and the Sun, by making careful measurements from various locations of the transit of Venus -- the apparent movement of the silhouette of Venus across the face of the Sun at the point when the Earth, Venus, and the Sun are all lined up.  Le Gentil, who had already done some work on this question, joined the French team working on the project, and was dispatched to Pondicherry, India, then a French colonial possession, where he'd been given permission by the king to set up an observatory.

Before Le Gentil's ship could get him there, though, the Seven Years' War broke out.  As different parts of India, and the islands of the Indian Ocean, were under the control of France and Britain, and those were on opposite sides of the conflict, ship travel in the region was iffy at best.  Le Gentil got stranded on Mauritius, and had a hell of a time finding anyone who would get him to India in time for the transit (6 June 1761).  He finally found a frigate whose captain said he'd get him to Coromandel, India, and from there Le Gentil could get another ship to Pondicherry in plenty of time -- but the first ship was first blown off course for five weeks, and then by the time they got to Coromandel they found out that Pondicherry had been taken by the British and they weren't allowing any French citizens to land there.

So Le Gentil had no choice but to return to Mauritius.  The transit took place while he was on board ship -- the weather was clear, but the seas were so rough and the ship pitching so wildly that he couldn't take any measurements from on board.

No worries, Le Gentil thought; because of the geometry of the orbits of Earth and Venus, Venusian transits come in pairs, eight years apart.  (Each pair, though, is separated by over a century.)  He decided to try and get measurements for the 1769 transit in Manila, Philippines, but the Spanish authorities weren't keen, so he went back to giving a go at Pondicherry again, which had been returned to French control in 1763.  He got there in 1768, built a special observatory to do his measurements, got everything ready...

... then the day of the transit, the clouds rolled in.

He was now zero for two.

Licking his wounds, he decided to return to France, but fate wasn't done yet.  The crew and passengers of his ship were struck by dysentery, and forced to put in on Réunion Island so they could recover.  (And, presumably, clean the ship.)  While in port, the ship was damaged in a storm and declared un-seaworthy, so once again he was stranded.  Finally he found a Spanish ship that was willing to take him home, and he arrived home in Paris in October of 1771, eleven years after he'd left for what was supposed to be an absence of a year or so.

When he got there, he found that much like Bilbo Baggins in The Hobbit, he'd been declared legally dead.  Not a single one of the letters he'd sent home during his voyage had arrived.  His wife had remarried, his estate had been plundered, and his seat at the Royal Academy of Sciences given to someone else.  He ended up in court for years trying to (1) prove he was actually still alive and wasn't an impostor, (2) get some of his belongings back, and (3) get re-appointed to the Academy.  (Eventually the king himself had to intervene to force the Academy to accept him again -- and also, to allow him to remarry without being guilty of bigamy.)

What's most remarkable about Le Gentil is that he seems to have lived up to his name (gentil is French for "friendly" or "kind").  He wrote a memoir with the cumbersome title Voyage dans les mers de l'Inde, fait par ordre du Roi, à l'occasion du passage de Vénus, sur le disque du Soleil, le 6 juin 1761 & le 3 du même mois 1769 par M. Le Gentil, de l'académie royale des sciences ("Voyage to the Indian Ocean, by Order of the King, for the Occasion of the Passage of Venus Across the Disk of the Sun, 6 June 1761 and the 3rd of the Same Month 1769, by Monsieur Le Gentil, of the Royal Academy of Sciences").  In it, you very much get the impression that Le Gentil had an "Oh, well, ha-ha, that's the way it goes" attitude toward all of his troubles; he never does what I would have done after the second setback, which is to scream "For fuck's sake, what now?" and start throwing heavy objects.

Guillaume Le Gentil died in Paris in October of 1792, at the age of 67.  This, in fact, might have been the best stroke of luck he ever had; he missed by only a few months the start of the horrific Reign of Terror, which -- to judge by the fate of poor, doomed Antoine Lavoisier -- had little respect for scientists.

Reading about Le Gentil's life, you have to wonder how one person could have such continual misfortune.  It reminds me of the line from Calvin & Hobbes, where Calvin's mom tells him, "Life is unfair," and Calvin responds, "I know, but why can't it ever be unfair in my favor?"  It sure seems like Le Gentil was on the receiving end of way too many bad turns of fate.  Even if I don't attribute it to his literally being ill-starred from birth, I can't help but feel a combination of pity and admiration for someone who kept doggedly persevering despite just about everything going wrong.

And maybe his tale of woe will also put things into perspective next time you think you're having a bad day.

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