Look upwards

Since (surprise!) we've all once again survived the apocalypse, and Saturday September 24, 2022 turned out to be less of a "day to remember" than a "day I've already kind of forgotten," today I'm going to turn to one of my favorite topics, namely: space.

I've been continually wowed by the images coming in from the James Webb Space Telescope.  When it was first deployed, the astronomer and engineers responsible for it told us we were going to be blown away by the quality of the data it would send us, and if anything, that's been an understatement.  We've seen images of astonishing crystal clarity, not only photographs of galaxies further away than anything yet studied but detailed views of objects much closer to home.

It's one of the latter that prompted me to write today's post, because the latest posted image from the JWST is of the planet Neptune.  Just a couple of months ago I did an entire post on how generally weird Neptune is; a lot of our information on it is old, however, having come from the Voyager 2 flyby a little over thirty years ago.  Since then, we've had to study it from farther away, and a lot of what we've learned has raised more questions than answers.

So I was really eager to see what JWST would find out about the eighth planet.  And it's started out with a bang.  Check out this image, showing the planet with its rings and several of its fourteen moons:

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

The rings are made of dark material -- this is actually the first time they've been directly observed since Voyager 2 (even the Hubble Space Telescope didn't have the optical resolution to see them).  The bright spots in the atmosphere are clouds of methane ice; the planet itself is not its usual deep cobalt blue because this image was taken in the near infrared range of the electromagnetic spectrum.

I find it deeply inspiring that despite the continuing turmoil down here on Earth, the scientists still have their eyes trained on deep space.  It also keeps us humble, you know?  Even as a child, when I'd look up at the sky through my little telescope, it always gave me a feeling of awe at how majestic, magnificent, and absolutely huge the universe was.

It reminds me of the words of Apollo 11 astronaut Michael Collins, about his experience of seeing the Earth from space: "The thing that really surprised me was that it [Earth] projected an air of fragility.  And why, I don’t know.  I don’t know to this day.  I had a feeling it’s tiny, it’s shiny, it’s beautiful, it’s home, and it’s fragile."

It's a perspective we all should have.

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Mysterious planet

You never hear people talking about the planet Neptune much.

The other planets are all famous for something or another.  Mercury is the closest to the Sun; Venus is ridiculously hot; Mars has been the subject of repeated visits; Jupiter's the biggest; Saturn has rings; and Uranus is best known for being a name you can't say without all the immature people giggling. 

To be fair, the unfortunately-named Uranus has some fascinating features, the most obvious of which is its axial tilt.  Its rotational axis is tipped at a bit over ninety degrees -- so it, in effect, rolls around its orbit on its side.  This means that at its summer solstice, its northern hemisphere is almost entirely illuminated all day long, and the entire southern hemisphere is in the dark; the opposite is true on the winter solstice.  (And given that its orbital period is 84 Earth years long, its winters are even longer than the ones we have here in upstate New York.)

But Neptune?  Other than the fact that it's a gas giant, and very far out in the Solar System, most people don't know much about it.

That's a shame, because it's a pretty interesting place.  Being about 1.5 times farther away from the Sun than Uranus, it's got a much longer year, at 164.8 Earth years.  It's really cold, with an average temperature somewhere around 70 K (-200 C, give or take).  Also, it's an interesting color -- a really deep, rich blue, something we didn't know until the first good images came back from the Voyager 2 flyby almost a little over thirty years ago.  Some of the color apparently comes from crystals of methane, but according to NASA, it's way deeper blue to be accounted for solely from that.  Their page on the planet says, "Uranus' blue-green color is also the result of atmospheric methane, but Neptune is a more vivid, brighter blue, so there must be an unknown component that causes the more intense color that we see.  The cause of Neptune's bluish tinge remains a mystery."

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

What brings this up is a study out of the University of Leicester showing that we haven't come close to exploring all of Neptune's oddities.  Currently the planet is in the southern hemisphere's summer; Neptune's axial tilt is a little over 28 degrees, so more than the Earth's (at 23.5) but nowhere near as tilted as Uranus (at 97.7).  So as with the Earth, when the southern hemisphere is pointed toward the Sun, it should be slowly warming up.

It's not.  It's cooling down.  The average temperature of the upper atmosphere in the southern hemisphere has dropped by 8 C.  (Remember that being a gas giant, Neptune has no well-defined surface.)  Even odder, there one place that's warming -- the planet's south pole, where the average temperature has gone up by 11 C.

These are not small changes, especially given how big Neptune is (seventeen times the mass of the Earth).  And the astronomers have no idea what's causing it.  It sounds like something that could be driven by convection -- atmospheric turnover, where warmer gases from lower down in the atmosphere rise, displacing colder, denser gases as they do so -- but that's a hell of a big convection cell if it's affecting the entire southern hemisphere of the planet.

Of course, when it comes to moving stuff around, Neptune is pretty good at it.  It has the fastest winds ever clocked in the Solar System (at a little over 1,900 km/hr).  An enormous storm called the "Great Dark Spot" was spotted by Voyager 2 in 1989 -- but by 1994, it had completely disappeared.

"I think Neptune is itself very intriguing to many of us because we still know so little about it," said astronomer Michael Roman, who was lead author on the paper, which appeared this week in The Planetary Science Journal.  "This all points towards a more complicated picture of Neptune’s atmosphere and how it changes with time."

So the most distant planet from the Sun is still largely a mystery, and this week's paper just added to its peculiarities.  Amazing that since its discovery by German astronomer Johann Gottfried Galle in 1846, we are still largely in the dark about what makes it tick.

And I, for one, find that absolutely fascinating.

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Hurricanes on Neptune

In yesterday's post, we looked at a peculiar, as-yet unexplained radio transmission from Proxima Centauri, but there's an awful lot we don't understand right here in our own Solar System.

Okay, most of it's not as exciting as a candidate for a signal from an extraterrestrial intelligence, although it must be mentioned that just last week scientists, using data from the Cassini probe, suggested that the chemistry of the ocean beneath the frozen surface of Enceladus (the sixth-largest moon of Saturn) shows signs of a complex chemistry that might be indicative of the presence of life.  If there's anything alive there, it's almost certainly nothing larger than microbes, but at this point, I'll take it.  If life can develop on a frigid, icy world like Enceladus, it further bolsters my conviction that life must be plentiful in the universe.

But leaving behind the topic of extraterrestrial life for a bit (face it, this is me writing this, it's bound to come up again soon), there's strange enough stuff to investigate right here and right now without postulating something we honestly don't have any hard evidence for.  Take, for example, the odd behavior of the storm on Neptune that was described in a press release from NASA last week.

To understand its oddity, a brief physics lesson.  Forgive me if this is familiar ground, but to see why the Neptunian observations are so weird, the average layperson might need some background explanation.

There's a phenomenon that occurs on planets' surfaces called the Coriolis effect.  The Coriolis effect, named after nineteenth century French physicist Gaspard Gustave de Coriolis, is a "fictitious force," a bit like "centrifugal force," that only occurs because we're in a non-inertial reference frame -- in this case, sitting on a spinning ball rather than standing still.  The simpler situation of centrifugal force not being a real force can be illustrated if you've ever ridden the Gravitron at a carnival, the ride where you stand with your back against the wall in a spinning cylinder, and you feel like you're getting pushed back and held against the wall.  The reality is that your body is just trying to obey Newton's First Law, of moving in a straight line at a uniform velocity, but you're being prevented from doing so by the rigid wall pushing you in toward the center of the cylinder.  In other words, the actual force is pointing inward (a "centripetal force"); you only feel like there's an outward-pointing force because you're moving in a rotating, non-inertial reference frame.

In the slightly more complicated situation of the Coriolis effect, here it manifests as an apparent deflection of the path of an object traveling from a straight line with respect to someone on the surface of the Earth.  In reality, of course, the object is traveling in a straight line, and you'd see that if you watched it from a stationary point in space; it's the observer, and the surface of the Earth (s)he is standing on, that isn't.  The result is that moving objects appear to be deflected clockwise in the Northern Hemisphere and counterclockwise in the Southern, which explains the rotation of hurricanes but does not account for water spiraling down a drain (drains are way too small for the Coriolis "force" to have a measurable effect; the swirl of water going down a drain is due to the shape of the basin and water's movement left over from when it was poured).

The Coriolis effect.  The object in question is moving from the upper left to the lower right.  The blue line shows its path as seen in an inertial reference frame (i.e. from space); the red curve shows its apparent position relative to a fixed point on the Earth's surface.  Notice that this gives the object a seemingly rightward (clockwise) deflection from the point of view of someone watching it from an earthbound perspective.  [GIF courtesy of Georgia State University]

The reason all this twisty stuff comes up is an observation of a storm on the planet Neptune.  Neptune is a gas giant, a planet large enough and cold enough that its atmosphere comprises a significant portion of the radius of the planet (rather than just a thin shell like ours).  The core is probably rocky, but we honestly don't know much about it, because the place is basically one enormously thick layer of clouds.

And it's turbulent.  The storms on Neptune dwarf the ones here on Earth; the one in question, which looks like a dark spot in the bright blue surface of the tops of the clouds, has a diameter larger than the Atlantic Ocean.  But even on Neptune, the laws of physics are strictly enforced, and when astronomers saw the massive hurricane heading toward the planet's equator -- where the Coriolis effect drops to zero, then picks up in the other direction in the Southern Hemisphere -- they thought the reversal of deflection would shear it to bits.

Neptune's enormous storm [Image courtesy of NASA]

But that didn't happen.  The storm appeared headed southward toward certain destruction, but then curved around and started heading north again.  Even weirder, it split off a smaller storm ("smaller" at 3,900 kilometers in diameter) which can be seen in the upper right of the planet's disc.  How it did that, and whether that had anything to do with the main storm's unexpected turn, is unknown.

"It was really exciting to see this one act like it's supposed to act and then all of a sudden it just stops and swings back," said Michael Wong, astrophysicist at the University of California-Berkeley, who led the team that made the discovery.  "That was surprising...  When I first saw the small spot, I thought the bigger one was being disrupted.  I didn't think another vortex was forming because the small one is farther towards the equator.  So it's within this unstable region.  But we can't prove the two are related.  It remains a complete mystery.  It was also in January that the dark vortex stopped its motion and started moving northward again.  Maybe by shedding that fragment, that was enough to stop it from moving towards the equator."

But the truth is, they really don't know for sure what caused the storm's odd trajectory.  It doesn't seem to be obeying the pattern we'd expect of a storm track -- although even here on Earth, predicting the path of a hurricane is an inexact science at best.  What it illustrates is that even in our own astronomical back yard, there are phenomena we're still working to explain.

Think about what kind of bizarre stuff we'll find when we are finally able to look farther afield.  What weird weather, geology, and oceanography might occur on planets around other stars -- planets that might have very elliptical orbits, rapid revolutions close in to the host star, or be spinning much faster than the Earth -- or maybe is tidally locked, so that the same side of the planet faces the star all the time?  I think we're in for some surprises, wherever we look.

Kind of boggles the mind, doesn't it?

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Not long ago I was discussing with a friend of mine the unfortunate tendency of North Americans and Western Europeans to judge everything based upon their own culture -- and to assume everyone else in the world sees things the same way.  (An attitude that, in my opinion, is far worse here in the United States than anywhere else, but since the majority of us here are the descendants of white Europeans, that attitude didn't come out of nowhere.)  

What that means is that people like me, who live somewhere WEIRD -- white, educated, industrialized, rich, and democratic -- automatically have blinders on.  And these blinders affect everything, up to and including things like supposedly variable-controlled psychological studies, which are usually conducted by WEIRDs on WEIRDs, and so interpret results as universal when they might well be culturally-dependent.

This is the topic of a wonderful new book by anthropologist Joseph Henrich called The WEIRDest People in the World: How the West Became Psychologically Peculiar and Particularly Prosperous.  It's a fascinating lens into a culture that has become so dominant on the world stage that many people within it staunchly believe it's quantifiably the best one -- and some act as if it's the only one.  It's an eye-opener, and will make you reconsider a lot of your baseline assumptions about what humans are and the ways we see the world -- of which science historian James Burke rightly said, "there are as many different versions of that as there are people."

[Note:  If you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

A celestial haystack

Today's cool science story is remarkable not only for the discovery the researchers made, but the extraordinary way in which they made it.

First, a little background.

In the earliest days of astronomy, skywatchers noticed that some of the points of light up there didn't behave like the others.  Instead of being fixed into position relative to one another, they shifted night to night and season to season.  The Greeks called these ἀστέρες πλανῆται, "astéres planetai, wandering stars" -- so our word "planet" translates loosely to "wanderer."

It took a long while to figure out exactly why this was happening, a process confounded by the ancients' determination that the skies be a place that was unchanging and eternal.  But once Copernicus and Kepler and the gang sorted out how things actually worked, it became obvious that the planets' apparent movement was because they were so much closer than the stars.  And other bodies in orbit around the Sun -- comets and asteroids, for example -- did the same thing.  This provided astronomers a method for finding hitherto-unknown bodies in the Solar System.

Look for a point of light that appears to move against the backdrop of distant stars, and you've found something that's (relatively) close by, and moving with respect to the Sun.

That's how the thousands of known asteroids and hundreds of known comets were discovered -- a painstaking study of the night skies, looking for something that's in one position today and a different one tomorrow.  It's how the remarkable object 'Oumuamua (the name means "advance scout" in Hawaiian) was discovered, the first verified object of interstellar origin to trek its way through the Solar System -- and which is almost certainly of completely natural origin, despite the wishes of those of us who grew up reading Arthur C. Clarke's Rendezvous with Rama.

As the bigger and nearer (and therefore brighter) objects are discovered, though, finding any remaining ones becomes increasingly difficult.  A typical view of the night sky in a decent telescope looks like this:

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

Now, imagine that your task is to compare this photograph to one exactly like it except for the fact that one of the fainter dots has moved a couple of millimeters.

That's what comet-hunters are up against.

All of that is background on today's amazing discovery, which is that astronomers at the University of Pennsylvania have combed through six years of data from the Dark Energy Survey Project, and have identified no less than three hundred "trans-Neptunian objects" -- dwarf planets, asteroids, and comets that orbit beyond Neptune.  In some cases, way beyond -- they found "TNOs" that were ninety times the distance of the Earth from the Sun (three times further away than Neptune itself is).

The way they did this is mind-boggling.  They started with seven billion objects in photographs -- dots of light, really -- and using sophisticated image-analysis software, eliminated any that were obviously not shifting position.  This whittled it down to a mere 22 million.  They then used the software in a giant game of connect-the-dots -- linked objects to two nearby ones to form a triangle, then checked to see if the triangle changed size or configuration from night to night.  After all was said and done, they identified three hundred out of the original seven billion that aren't stars, but small objects in orbit around the Sun out past the orbit of Neptune.

This gives the phrase "needle in a haystack" new meaning, doesn't it?

The most amazing thing about this is that the data they've collected and analyzed will be invaluable for astronomers looking for much larger objects circling the Sun much farther away.  Now that the TNOs have been identified, keeping track of their positions will allow for calculation of their orbits, so it will be possible to see if any are being "gravitationally perturbed" by larger objects out there.  This was the way Alexis Bouvard discovered Neptune -- small disturbances in the motion of Uranus clued him and others in to the possibility that there was another planet out there pulling on it, deflecting it from its predicted path.  Now we've got three hundred possible sources of data to use as a means to locate other larger objects that may be out there.

"There are lots of ideas about giant planets that used to be in the solar system and aren't there anymore, or planets that are far away and massive but too faint for us to have noticed yet," said study co-author Gary Bernstein.  "Making the catalog is the fun discovery part.  Then when you create this resource; you can compare what you did find to what somebody's theory said you should find."

Which is all kind of stunning to me.  Our level of sophistication in studying the skies has increased so dramatically in the last twenty years that new and fascinating discoveries are being made nearly on a daily basis.  It also makes me wonder what else is out there still to discover -- surely worlds upon worlds, out there in the vastness of space, just waiting for us to find them.

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This week's Skeptophilia book-of-the-week is brand new: Brian Greene's wonderful Until the End of Time.

Greene is that wonderful combination, a brilliant scientist and a lucid, gifted writer for the scientifically-inclined layperson.  He'd already knocked my socks off with his awesome The Elegant Universe and The Fabric of the Cosmos (the latter was made into an equally good four-part miniseries).

Greene doesn't shy away from difficult topics, tackling such subjects as relativity, quantum mechanics, and the nature of time.  Here, Greene takes on the biggest questions of all -- where the universe came from, how it has evolved and is evolving, and how it's going to end.

He begins with an observation that as a species, we're obsessed with the ideas of mortality and eternity, and -- likely unique amongst known animals -- spend a good part of our mental energy outside of "the now," pondering the arrow of time and what its implications are.  Greene takes a lens to this obsession from the standpoint of physics, looking at what we know and what we've inferred about the universe from its beginnings in the Big Bang to its ultimate silent demise in the "Heat Death" some billions or trillions of years in the future.

It's definitely a book that takes a wide focus, very likely the widest focus an author could take.  And in Greene's deft hands, it's a voyage through time you don't want to miss.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]