Complex Numbers

Upward Spiral

I'll be on the road for some unknown amount of time tomorrow [edit: I meant today. I'm writing this before I go to sleep, so tomorrow is today and today is totally tomorrow, while yesterday is but a fading memory as usual], stopping who knows where, so I figured I'd get in this last entry before traveling.

Speaking of traveling, here are some places none of us will ever go (probably):

    In the Milky Way’s Stars, a History of Violence  
Our galaxy's stars keep a record of its past. By reading those stories, astronomers are learning more about how the Milky Way came to be — and about the galaxy we live in today.

The amazing thing is that we can figure any of this out at all. It's been barely a century since we learned that there's more to the universe than our familiar galaxy, the discovery of which leads the linked article.

Late in the evening of October 5, 1923, Edwin Hubble sat at the eyepiece of the Hooker telescope at the Mount Wilson Observatory, atop the mountains overlooking the Los Angeles basin.

Visiting that telescope was the highlight of my trip to L.A. last year.

One might think, "What use is a telescope in L.A.?" Well, one, it's on a pretty high mountain and, two, I don't think the area was quite as smoggy or light-polluted a hundred years ago.

With the cleaving of the cosmos into a home galaxy and a larger universe, the study of our finite home — and how it exists within that universe — could begin in earnest.

I mean, sure, it was a paradigm shift much like the heliocentric model of the solar system centuries earlier, and a Big Deal, but it's not like we hadn't been studying the stars.

The latest results, amassed over the past four years, are now painting a picture of our home as a unique place, at a unique time.

To recap, the history of our thinking about our place in the universe went something like:

1) We're special and everything revolves around us.
2) We're not that special and not the center of the universe.
3) The universe is unimaginably big, and we're a rounding error.
4) Wait, maybe we are special.

We have been lucky, it seems, to live near a particularly quiet star on the calm fringes of a middle-aged, oddly tilted, loosely spiraling galaxy that has been largely left alone for most of its existence.

As regular readers know, I'm not discounting the power of luck, but if those conditions hadn't been relatively stable, we wouldn't be here to congratulate ourselves on our luck.

From the Earth’s surface — if you are somewhere very dark — you can only see the bright stripe of the Milky Way’s galactic disk, edge-on. But the galaxy we live in is so much more complicated.

It's getting harder and harder to find a place where you can see that. Oh, incidentally, it's called the Milky Way because of its appearance to the eye: a pale streak, like a road ("way.") It's translated from Latin's "via lactea," which, like a lot of things in Rome, came from Greek: galaxías kýklos. Hence "galaxy." Point being that the word, now applied to collections of stars all across the universe, shares a root with "milk" words like lactose and lactate.

I mention this simply because I find it amusing, if horribly mammal-centric.

A supermassive black hole churns at its center, surrounded by the “bulge,” a knot of stars containing some of the galaxy’s oldest stellar denizens.

Good to know it's not just middle-aged people who develop a "bulge."

Another digression: black holes have a scary reputation, like they're going to eat everything around them. And they do, but only up to a certain distance. Past that distance, they work just like any other massive object; you could orbit a black hole for a very long time, in the same way the Earth has been orbiting the sun for a very long time without showing any signs of falling in.

Next comes the “thin disk” — the structure we can see — where most of the Milky Way’s stars, including the sun, are partitioned into gargantuan spiraling arms.

One thing I've never been really clear on is how the spiral arms formed or are maintained.

While the article doesn't shed much light (pun intended) on that, it does go into the latest observations and theories about our galaxy's structure and how it got here.

And it's all very fascinating, at least to me, but I don't have much to comment on the rest of the article except to note that, given all the paradigm shifts we've already seen in cosmology, I'd expect more. And I look forward to it.