Betelgeuse, Betelgeuse, Betelgeuse

There’s been a lot of talk in the news lately about the star Betelgeuse, and whether it’s about to explode and go nova. The main reason this discussion is happening is because the star suddenly got very dim very quickly, and dimmer than we have ever observed it to be. The dimming itself isn’t unusual because Betelgeuse is a variable star, meaning that its apparent brightness changes. What’s unusual now is the magnitude of that change. In only two months, Betelgeuse dropped from 10th brightest star in the northern night sky to 21st.

Stars and the physics in them have always fascinated me because they are a perfect example of macro and micro coming together — the very large displaying the power of the very tiny at work.

Fusion without confusion

What is a star? Simply put, it’s a big ball of gas that is so massive that its own gravity makes it ignite in nuclear fusion, creating heat and light. As far as we know, the very first stars started out as cloud of the lightest, simplest element, hydrogen, which in its basic form is one proton with one electron bound to it. I say “bound to” rather than “orbiting” because that old model of discrete little electrons circling the nucleus like planets orbit the Sun is just wrong. It’s better to think of the electron or electrons as existing as a potential force spread out over a certain area statistically, with the shapes and volumes of those areas varying with the energy of the electron. It’s not in one place at any given time, but it’s likely to be in certain places and not in others, and this goes for every electron in the atom.

Yes, welcome to the weirdness of quantum physics. The layman’s takeaway here is that the electrons create what you can think of as a force field far “above” the nucleus that keeps other nuclei from getting too close. They’re like the walls of houses that keep the nosy neighbors from wandering in.

And that works just fine on most scales. The electrons are doing all of the work so that the atoms in your cells don’t fuse together and it even works right up to the level you can perceive. When you touch a table, for example, you aren’t really touching it. Rather, the electrons in your finger are bumping against the electrons in the table and are acting as mutual bouncers keeping each other out so that your hand and the table don’t merge.

Oh, sure, you will exchange some electrons with whatever you touch because they can just be finicky like that. But, for the most part, this is an impenetrable barrier that keeps things well-defined.

It doesn’t break down until enormous forces come into play. In the case of stars, that force is called gravity, and it’s not until that ball of hydrogen reaches a certain density that things begin to happen. Mainly, the force of gravity working on it becomes enough to overcome the force of the electrons maintaining boundaries. All of a sudden, those neat electron orbital shells go wonky, and the protons start to get to know each other. Now, normally, they would repel because they have the same charge, but their charges are so much weaker that by this point it doesn’t matter. Protons start to get forced together, and then the magic happens.

It’s elementary

I won’t get too heavy into the physics here — you can learn more if you’d like — but the key point is that this gravitational mushing turns hydrogen into helium, the next heaviest element, which has two protons, two neutrons, and two electrons, and in the process a lot of energy (relatively speaking) gets released.

This continues on for a long time until the hydrogen has almost but not quite run out, at which point the star starts to smoosh all of that helium into carbon, and the process cascades from there. Combining each new element with more helium runs down the chain to create oxygen, neon, magnesium, silicon, sulfur, argon, calcium, titanium, chromium, and then iron.

A star is basically a forge that creates the heavier elements that become the building blocks of planets, all subsequent new stars (which don’t start as pure hydrogen), and, eventually, life.

There’s one critical element to mention, though: while the force of gravity has been enough to make the fusion happen, at the same time the opposing force of the energy released by that fusion has been enough to push back and create a sort of equilibrium so that the star doesn’t collapse or expand. It pretty much maintains its size.

And then iron synthesis comes along, and it’s a game changer. Why? Because, unlike those other fusion reactions, this one doesn’t produce sufficient energy to fight gravity any longer. Boom, it’s like a light switch is turned off. All of a sudden, the floorboards give out, and all of that mass up above the ceiling is free to come crashing down into the basement, and that doesn’t go well when it hits bottom. Above a certain original mass, you get a black hole. Below it, you get an enormous explosion which scatters all of those elements outward and releases an incredible amount of energy.

It would be a super nova

If that happened to Betelgeuse during 14th or 15th centuries, we’d see it here soon, since the star is only about six hundred light years away. For a while, it would be brighter than the full Moon at night, and visible during the day. And it couldn’t happen to a nicer star. It’s one that you’ve probably seen since its constellation is so memorable.

Betelgeuse is the right shoulder of Orion, assuming that he’s facing us, and is visibly red from down here. In official terms, the star is known as Alpha Orionis, meaning the first, or brightest, star in the constellation Orion. The interesting part about this designation is that it’s only sometimes the brightest, again because of the variable thing. Rigel is often brighter, but when Sir John Herschel made his observations and his catalog, Betelgeuse was brighter, so it got the A rating.

If you’re wondering about the name of the star, it’s got nothing to do with the Tim Burton film. Rather, it comes from the Arabic name for it, إبط الجوزاء (‘iibt aljawaza’). If you pronounce it fast enough a few times, it kind of starts to sound like “Betelgeuse.”

Just don’t say it three times. Or, maybe, do — because seeing a supernova of this magnitude at this point in our history wouldn’t only be great for humanity in general, it would be a boon to many different sciences. The last visible supernova happened in 1987, but it was only visible from the Southern Hemisphere, and it was about 160,000 light years away, or just over 49,000 parsecs.

This one would be visible by everyone in the Northern Hemisphere, day and night, for a good period of time, and it would serve to make people aware of the universe out there, and maybe even ask questions and listen to scientists. It might even get them to realize that the ultimate survival route for the entire human race — and a lot of other species on this planet — is to get off of this planet and start colonizing, except to do it in a low-impact and benevolent way, rather than the slash-and-burn methods used by our ancestors who raped and pillaged their way out of Europe and into the “new” world. (Funny how none of it was new to the people who had been living there already.)

Anyway… here’s to hoping that one of the most violent events in the universe can grace our night and day skies soon, and pull us out of ourselves. Maybe we do need a cataclysmic event to unite the planet — but that doesn’t mean that the cataclysm needs to be anywhere near us. Just that we need to be aware of it.

What better screen than the sky above?

If you say the name three times, it appears. Betelgeuse.

Betelgeuse.

Betelgeuse!

Forces of nature

If you want to truly be amazed by the wonders of the universe, the quickest way to do so is to learn about the science behind it.

And pardon the split infinitive in that paragraph, but it’s really not wrong in English, since it became a “rule” only after a very pedantic 19th century grammarian, John Comly, declared that it was wrong to do so — although neither he nor his contemporaries ever called it that. Unfortunately, he based this on the grammar and structure of Latin, to which that of English bears little resemblance.

That may seem like a digression, but it brings us back to one of the most famous modern split infinitives that still resonates throughout pop culture today: “To boldly go where no one has gone before,” and this brings us gracefully back to science and space.

That’s where we find the answer to the question “Where did we come from?” But what would you say exactly is the ultimate force that wound up directly creating each one of us?

One quick and easy answer is the Big Bang. This is the idea, derived from the observation that everything in the universe seems to be moving away from everything else, so that at one time everything must have been in the same place. That is, what became the entire universe was concentrated into a single point that then somehow exploded outward into, well, everything.

But the Big Bang itself did not instantly create stars and planets and galaxies. It was way too energetic for that. So energetic, in fact, that matter couldn’t even form in the immediate aftermath. Instead, everything that existed was an incredibly hot quantum foam of unbound quarks. Don’t let the words daunt you. The simple version is that elements are made up of atoms, and an atom is the smallest unit of any particular element — an atom of hydrogen, helium, carbon, iron, etc. Once you move to the subatomic particles that make up the atom, you lose any of the properties that make the element unique, most of which have to do with its atomic weight and the number of free electrons wrapped around it.

Those atoms in turn are made up of electrons that are sort of smeared out in a statistical cloud around a nucleus made up of at least one proton (hydrogen), and then working their way up through larger collections of protons (positively charged), an often but not always equal number of neutrons (no charge), and a number of electrons (negatively charged) that may or may not equal the number of protons.

Note that despite what you might have learned in school, an atom does not resemble a mini solar system in any particular way at all, with the electron “planets” neatly orbiting the “star” that is the nucleus. Instead, the electrons live in what are called orbitals and shells, but they have a lot more to do with energy levels and probable locations than they do with literal placement of discrete dots of energy.

Things get weird on this level, but they get weirder if you go one step down and look inside of the protons and neutrons. These particles themselves are made up of smaller particles that were named quarks by Nobel Prize winner Murray Gell-Man as a direct homage to James Joyce. The word comes from a line from Joyce’s book Finnegans Wake, which itself is about as weird and wonderful as the world of subatomic science. “Three quarks for muster mark…”

The only difference between a proton and a neutron is the configuration of quarks inside. I won’t get into it here except to say that if we call the quarks arbitrarily U and D, a proton has two U’s and one D, while a neutron has two D’s and one U.

And for the first few milliseconds after the Big Bang, the universe was an incredibly hot soup of all these U’s and D’s flying around, unable to connect to each other because the other theoretical particles that could have tied them together, gluons, couldn’t get a grip. The universe was also incredibly dark because photons couldn’t move through it.

Eventually, as things started to cool down, the quarks and gluons started to come together, creating protons and neutrons. The protons, in turn, started to hook up with free electrons to create hydrogen. (The neutrons, not so much at first, since when unbound they tend to not last a long time.) Eventually, the protons and neutrons did start to hook up and lure in electrons, creating helium. This is also when the universe became transparent, because now the photons could move through it freely.

But we still haven’t quite gotten to the force that created all of us just yet. It’s not the attractive force that pulled quarks and gluons together, nor is it the forces that bound electrons and protons. That’s because, given just those forces, the subatomic particles and atoms really wouldn’t have done much else. But once they reached the stage of matter — once there were elements with some appreciable (though tiny) mass to toss around, things changed.

Vast clouds of gas slowly started to fall into an inexorable dance as atoms of hydrogen found themselves pulled together, closer and closer, and tighter and tighter. The bigger the cloud became, the stronger the attraction until, eventually, a big enough cloud of hydrogen would suddenly collapse into itself so rapidly that the hydrogen atoms in the middle would slam together with such force that it would overcome the natural repulsion of the like-charged electron shells and push hard enough to force the nuclei together. And then you’d get… more helium, along with a gigantic release of energy.

And so, a star is born. A bunch of stars. A ton of stars, everywhere, and in great abundance, and with great energy. This is the first generation of stars in the universe and, to quote Bladerunner, “The light that burns twice as bright burns half as long.” These early stars were so energetic that they didn’t make it long, anf they managed to really squish things together. You see, after you turn hydrogen into helium, the same process turns helium into heavier elements, like lithium, carbon, neon, oxygen, and silicon. And then, once it starts to fuse atoms into iron, a funny thing happens. Suddenly, the process stops producing energy, the star collapses into itself, and then it goes boom, scattering those elements aback out into the universe.

This process will happen to stars that don’t burn as brightly, either. It will just take longer. The first stars lasted a few hundred million years. A star like our sun is probably good for about ten billion, and we’re only half way along.

But… have you figured out yet which force made these stars create elements and then explode and then create us, because that was the question: “What would you say exactly is the ultimate force that wound up directly creating each one of us?”

It’s the same force that pulled those hydrogen atoms together in order to create heavier elements and then make stars explode in order to blast those elements back out into the universe to create new stars and planets and us. It’s the same reason that we have not yet mastered doing nuclear fusion because we cannot control this force and don’t really know yet what creates it. It’s the same force that is keeping your butt in your chair this very moment.

It’s called gravity. Once the universe cooled down enough for matter to form — and hence mass — this most basic of laws took over, and anything that did have mass started to attract everything else with mass. That’s just how it works. And once enough mass got pulled together, it came together tightly enough to overcome any other forces in the universe.  Remember: atoms fused because the repulsive force of the negative charge of electrons was nowhere near strong enough to resist gravity, and neither was the nuclear force between protons and neutrons.

Let gravity grow strong enough, in fact, and it can mash matter so hard that it turns every proton in a star into a neutron which is surrounded by a surface cloud of every electron sort of in the same place, and this is called a neutron star. Squash it even harder, and you get a black hole, a very misunderstood (by lay people) object that nonetheless seems to actually be the anchor (or one of many) that holds most galaxies together.

Fun fact, though. If our sun suddenly turned into a black hole (unlikely because it’s not massive enough) the only effect on the Earth would be… nothing for about eight minutes, and then it would get very dark and cold, although we might also be fried to death by a burst of gamma radiation. But the one thing that would not happen is any of the planets suddenly getting sucked into it.

Funny thing about black holes. When they collapse like that and become one, their radius may change drastically, like from sun-sized to New York-sized, but their gravity doesn’t change at all.

But I do digress. Or maybe not. Circle back to the point of this story: The universal force that we still understand the least also happens to be the same damn force that created every single atom in every one of our bodies. Whether it has its own particle or vector, or whether it’s just an emergent property of space and time, is still anybody’s guess. But whichever turns out to be true, if you know some science, then the power of gravity is actually quite impressive.