The stellar forges

A criticism sometimes aimed at us science types is that our obsession with naming, classifying, and explaining everything in the universe robs us of its wonder.  Why, they ask, do we have to get so damn technical about everything?  Why can't we just look at the stars, or the flowers, or a bird in flight, and appreciate their beauty?

Well, needless to say, I disagree with that pretty strenuously.  My understanding of science -- which, admittedly, is that of a reasonably well-read layperson's -- only adds to my sense of wonder.  For me, it's a case of the more you know, the more amazing it gets.

Let me give you an example of that -- a piece of research out of the University of Arizona that used the James Webb Space Telescope to peer far out into space (and thus, far back in time), and found something astonishing.  Something, in fact, that would appear quite mundane, meriting only a "So what?', if you didn't know some science.

Here's a capsule summary of the research -- then an explanation of why it's way cooler, and more surprising, than it appears at first.

The JWST just released a spectral analysis of a galaxy called JADES-GS-z14-0, which is about 13.5 billion light years away.  That's a pretty impressive feat; this means the light from it left on its journey to us when the universe was only two percent of its current age.  This, in fact, means the galaxy itself formed not long (in astronomical terms) after the cosmic microwave background radiation, the earliest remnants of radiation released when the universe settled down enough to allow photons to travel unimpeded.

Just seeing JADES is amazing enough.  "Imagine a grain of sand at the end of your arm," said Jakob Helton, who led the research.  "You see how large it is on the sky -- that's the size of the region we looked at."

The shocker came when they did an analysis of its spectrum, and found that it had high amounts of oxygen.  But why this is surprising -- why, in fact, it's going to force a rethinking of our understanding of how stars and galaxies form -- is where you have to know some background.

When heated or otherwise energized, each element emits a characteristic fingerprint of frequencies of light known as its emission spectrum.  The fact that these specific frequencies and no others are emitted was key to the development of quantum theory; energy levels in atoms are quantized, or exist in discrete steps, and an atom can no more emit a different frequency of light than you could go down a step-and-three-quarters on your staircase.  Because of these spectral fingerprints, it's now possible to determine the composition of distant stars by looking for the characteristic spectral lines of common elements in the star's spectrum.  This is how Helton et al. figured out that JADES contains large amounts of oxygen.

The emission spectrum of oxygen [Image is in the Public Domain]

Thing is, it shouldn't.  We have lots of oxygen here on Earth because the primordial cloud from which the Solar System condensed had a bunch of it; so, in fact, does the Sun, since it formed from the same cloud.  Alien astronomers could look at the Sun through their telescopes and figure that out the same way that we do.  But oxygen, it turns out, doesn't form all that readily.  The Solar System is oxygen-enriched because the Sun is (at least) a third-generation star.  In the very early universe, when there was nothing much around but hydrogen, helium, and trace amounts of lithium -- the atoms that were formed during the Big Bang itself -- stars had vanishingly small "metal content."  (To astrophysicists, "metals" are any elements heavier than helium.)  As those first stars underwent fusion in their cores, hydrogen was converted to helium, then helium to lithium and carbon; at the end of their lives, those stars that were heavy enough went supernova, and the pressures and temperatures of those colossal explosions not only generated "metals" but distributed them back into space.

Second-generation stars formed from the debris left behind by the explosion of first-generation stars.  Those second-generation stars, during the course of their lives and deaths, would have produced more "metals," and the cycle repeated, ultimately leading to the richness of composition we see in our own Solar System.

But it takes a while.  The amount of oxygen even in early third-generation stars is pretty small.  So where did all the oxygen in an extremely early galaxy like JADES come from?

We don't know.  "It's a very complicated cycle to get as much oxygen as this galaxy has," said study senior author George Rieke.  "So, it is genuinely mind boggling."

So there's evidently something about star formation and galaxy evolution we're missing.  Stars forming only three hundred million years after the Big Bang should be just about entirely hydrogen and helium.  And chances are, JADES is almost certainly not the only anomalous early object.  "The fact that we found this galaxy in a tiny region of the sky means that there should be more of these out there," Helton said. "If we looked at the whole sky, which we can't do with JWST, we would eventually find more of these extreme objects."

For me, it's lovely to look up into the sky on a clear night, but my enjoyment is much enhanced by the fact that I know a little bit about what I'm looking at.  The stars are stellar forges, creating all the matter around us -- we are truly, as Carl Sagan famously said, "made of star stuff."

In short: science itself is beautiful.  Understanding how the world works should do nothing but increase our sense of wonder.  If scientific inquiry isn't accompanied by a sense of "Wow, this is amazing!", you're doing it wrong.  I'll end with a quote from Nobel Prize winning physicist Richard Feynman, who in his 1988 book What Do You Care What Other People Think? had the following to say:

I have a friend who's an artist, and he sometimes takes a view which I don't agree with.  He'll hold up a flower and say, "Look how beautiful it is," and I'll agree.  But then he'll say, "I, as an artist, can see how beautiful a flower is.  But you, as a scientist, take it all apart and it becomes dull."  I think he's kind of nutty. …  There are all kinds of interesting questions that come from a knowledge of science, which only adds to the excitement and mystery and awe of a flower.  It only adds.  I don't understand how it subtracts.

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All that glitters

If you own anything made of gold, take a look at it now.

I'm looking at my wedding ring, made of three narrow interlocked gold bands.  It's a little scratched up after twenty-two years, but still shines.

Have you ever wondered where gold comes from?  Not just "a gold mine," but before that.  If you know a little bit of physics, it's kind of weird that the periodic table doesn't end at atomic number 26.  The reason is a subtle but fascinating one, and has to do with the binding energy curve.

The vertical axis is a measure of how tightly the atom's nucleus is held together.  More specifically, it's the amount of energy (in millions of electron-volts) that it would take to completely disassemble the nucleus into its component protons and neutrons.  From hydrogen (atomic number = 1) up to iron (atomic number = 26), there is a relatively steady increase in binding energy.  So in that part of the graph, fusion is an energy-releasing process (moves upward on the graph) and fission is an energy-consuming process (moves downward on the graph).  This, in fact, is what powers the Sun; going from hydrogen to helium is a jump of seven million electron-volts per proton or neutron, and that energy release is what produces the light and heat that keeps us all alive.

After iron, though -- specifically after an isotope of iron, Fe-56, with 26 protons and 30 neutrons -- there's a slow downward slope in the graph.  So after iron, the situation is reversed; fusion consumes energy, and fission releases it.  This is why the fission of uranium-235 generates energy, which is how a nuclear power plant works.

It does generate a question, though.  If fusion in stars is energetically favorable, increasing stability and releasing energy, up to but not past iron -- how do the heavier elements form in the first place?  Going from iron to anywhere would require a consumption of energy, meaning those will not be spontaneous reactions.  They need a (powerful) energy driver.  And yet, some higher-atomic-number elements are quite common -- zinc, iodine, and lead come to mind.

Well, it turns out that there are two ways this can happen, and they both require a humongous energy source.  Like, one that makes the core of the Sun look like a wet firecracker.  Those are supernova explosions, and neutron star collisions.  In fact, a while back, two astrophysicists -- Szabolcs Marka of Columbia University and Imre Bartos of the University of Florida -- found evidence that the heavy elements on the Earth were produced in a collision between two neutron stars, on the order of a hundred million years before the Solar System formed.

This is an event of staggering magnitude.  "If you look up at the sky and you see a neutron-star merger a thousand light-years away," Marka said, "it would outshine the entire night sky."

What apparently happens is when two neutron stars -- the ridiculously dense remnants of massive stellar cores -- run into each other, it is such a high-energy event that even thermodynamically unfavorable (energy-consuming) reactions can pick up enough energy from the surroundings to occur.  Then some of the debris blasted away from the collision gets incorporated into forming stars and planets.  And here we are, still with tons of lightweight elements, but a surprisingly high amount of heavier ones, too.

But how do they know it wasn't a nearby supernova?  Those are far more common in the universe than neutron star collisions.  Well, the theoretical yield of heavy elements is known for each, and the composition of the Solar System is far more consistent with a neutron star collision than with a supernova.  And as for the timing, a chunk of the heavy isotopes produced are naturally unstable, so decaying into lighter nuclei is favored (which is why heavy elements are often radioactive; the products of decay are higher on the binding energy curve than the original element was).  Since this happens at a set rate -- most often calculated as a half-life -- radioactive isotopes act like a nuclear stopwatch, analogous to the way radioisotope decay is used to calculate the ages of artifacts, fossils, and rocks.  Backtracking that stopwatch to t = 0 gives an origin of about 4.7 billion years ago, or a hundred million years before the Solar System coalesced.

So next time you look at anything made of heavier elements -- gold or silver or platinum, or (more prosaically) the zinc plating on a galvanized steel pipe -- ponder for a moment that it was formed in a catastrophically huge collision between two neutron stars, an event that released more energy in a few seconds than the Sun will produce over its entire lifetime.  Sometimes the most ordinary things have a truly extraordinary origin -- something that never fails to fascinate me.

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Elaborate nonsense

As I mentioned in yesterday's post, I can understand how fear and lack of knowledge can drive you to accept counterfactual nonsense.  I also get how wishful thinking could draw you in to a set of beliefs, if they line up with the way you would like the universe to work, even though, as my grandma used to say, "Wishin' don't make it so."

This combination of desire for the world to be other than it is, and fear of what the world actually is, probably drives most superstition.  All, as I said, understandable, given human nature.

But what continually baffles me is how byzantine some of those beliefs become.  I can accept that it might be an attractive model for some people that the position of the stars and planets somehow guides your life; but I start really wondering once you start coming up with stuff like the following (from Susan Miller's astrology site, on a page devoted to predictions for this month for my astrological sign, Scorpio):

Here is why I say that: Sometimes, in about 20 percent of the cases, an eclipse will deliver news a month to the day later plus or minus five days. More rarely, an eclipse will introduce news one month to the day before it occurs, but only in about 5 percent of the cases. In most cases, 75 percent of the time, an eclipse will deliver some sort of news that things are about to change almost instantly.

This eclipse will be in Scorpio, 11 degrees, and will come conjunct Saturn. This alone says that the decision you make now will be a big one, and that you will commit all your energy to this decision. You will be in a serious mode, and it appears a promise you make now will last a very long time, possibly forever. Mars and Pluto are your two ruling planets (Scorpio is one of the few signs that have two rulers), and remarkably both will be supportive by tight mathematical angles to this eclipse. This tells me that the final outcome of this eclipse will be very positive. Every eclipse has two acts, so see how events unfold in coming weeks.

Yes, it's bullshit; but it's really elaborate bullshit.  You might criticize these people for pushing fiction as reality, but you have to admit that they spend a lot of time crafting their fiction.

I ran across an unusually good example of this yesterday on the Skeptic subreddit, which is a wonderful place to go for articles debunking pseudoscience.  The site I found posted there is called "TCM - the 24-hour Organ Qi Cycle," which immediately should raise red flags -- "TCM" is traditional Chinese medicine, much of which has been double-blind tested and found to be worthless; and "qi" is a pattern for "energy flow" through the body that basically is non-existent, making "qi" only useful as an easy way of getting rid of the "Q" tile in a game of Scrabble.

What this site purports to do is to get you to "balance your body" using information about when during the day you feel most ill-at-ease.  This then tells you what organ in your body is "out of balance" and which of the "elements" you should pay attention to.  And no, I'm not talking about anything off the periodic table; we're back to a medieval "Earth," "Fire," "Water," "Metal," "Wood," and "Ministerial Fire" model, although the last-mentioned sounds like what they used back in the Dark Ages to burn people at the stake for heresy.

So, naturally, I had to check out what my own out-of-balance part was.  I'm frequently awake, and restless, at 3 AM - 5 AM, so I rolled the cursor over the "color wheel" and found that this means my lungs are out of balance.  "The emotions connected to the lungs are Grief and Sadness," I was told, which makes sense for the time of day because if I'm awake then it means I won't be able to get back to sleep before my alarm goes off.  It goes on to ask me some questions, to wit:  "Have you buried your grief?  Are you sad?  Are you always sighing?  It is most healthy to express your emotions as you feel them.  You may need to express your emotions by crying, writing and/or talking to a friend."

Well, thanks for caring, and everything, but I'm actually doing okay, and don't sigh all that much, except at faculty meetings.

Oh, but I am told that if I can get my lungs in balance, I'll have "lustrous skin."  And who could resist that?

On it goes.  If your small intestine is out of balance, you should eat only "vital foods chock full of enzymes."  If you have diarrhea, you need to "strengthen your spleen qi."  If your "kidneys are deficient," you won't have much in the way of sex drive, but you can bring them back into balance by eating black sesame seeds, celery, duck, grapes, kidney beans, lamb, millet, oysters, plums, sweet potatoes, raspberries, salt, seaweed, strawberries, string beans, tangerines, walnuts, and yams.

The entire time I was looking at this site, I kept shaking my head and saying, "How do you know any of this?"  The stuff on this website seems to fall into two categories -- blatantly obvious (e.g. "crying if you're sad helps you to feel better") and bizarrely abstruse (e.g. "engaging in loving sex keeps your pericardium healthy").

I suppose the elaborateness is understandable from one angle; if you want people to believe what you're saying, you'll probably have better success if you make your sales pitch sound fancy.  Convoluted details convince people, especially people who don't know much in the way of science and logic.  So the intricacy of some pseudoscientific models is explainable from the standpoint that the purveyors of this kind of foolishness will sound like scientists, and therefore be persuasive, only if they couch their message in terms that make it appear they've tapped into a realm of knowledge unavailable to the rest of us slobs.

Or, as my dad put it: "If you can't wow 'em with your brilliance, baffle 'em with your bullshit."