Astronomy

Astronomy

The Science of Stars

Talking of science. What is science? There are lots of definitions of science,but I’ll say that it’s a body of knowledge, and a method of how we learned that knowledge. Science tells us that stuff we know may not be perfectly known; it may be partly or entirely wrong. We need to watch the Universe, see how it behaves, make guesses about why it’s doing what it’s doing, and then try to thinkof ways to support or disprove those ideas. That last part is important. Science must be, above all else, honestly if we really want to get to the bottom of things. Understanding that our understanding might be wrong is essential, and trying to figure out the ways we may be mistaken is the only way that science can help us find our way to the truth, or at least the nearest approximationto it. Science learns. We meander a bit as we use it, but in the long run we get ever closer to understanding reality, and that is the strength of science. And it’s all around us!

Whether you know it or not, you’re soaking in science. You’re a primate. You have mass. Mitochondria in your cells are generating energy. Presumably,you’re breathing oxygen. But astronomy is different. It’s still science, ofcourse, but astronomy puts you in your place. Because of astronomy, I know we’re standing on a sphere of mostly molten rock and metal 13,000 kilometers across, with a fuzzy atmosphere about 100 km high, surrounded by a magnetic field that protects us from the onslaught of subatomic particles from the Sun 150 million km away, which is also flooding space withlight that reaches across space, to illuminate the planets, asteroids, dust, and comets,racing out past the Kuiper Belt, through the Oort Cloud, into interstellar space, pastthe nearest stars, which orbit along with gas clouds and dust lanes in a gigantic spiralgalaxy we call the Milky Way that has a supermassive black hole in its center, and is surroundedby 150 globular clusters and a halo of dark matter and dwarf galaxies, some of which it’seating, all of which can be seen by other galaxies in our Local Group like Andromedaand Triangulum, and our group is on the outskirts of the Virgo galaxy cluster, which is partof the Virgo supercluster, which is just one of many other gigantic structures that stretchmost of the way across the visible Universe, which is 90-billion light years across andexpanding every day, even faster today than yesterday due to mysterious dark energy, andeven all that might be part of an infinitely larger multiverse that extends forever bothin time and space.

See? Astronomy puts you in your place. But what exactly is astronomy? This isn’tnecessarily an obvious thing to ask. When I was a kid, it was easy: Astronomy is thestudy of things in the sky. The sun, moon, stars, galaxies, and stuff like that. Butit’s not so easy to pigeonhole these days. Take, for example, Mars. When I haul my ‘scopeout to the end of my driveway and look at Mars, that’s astronomy, right? Of course!But what about the rovers there? Those machines aren’t doing astronomy, surely. They’re doing chemistry, geology, hydrology, petrology… everything but astronomy! So nowadays, what’s astronomy? I’d say it’s still studying stuff in the sky, but it’s branched out quite a bit from there.Borders between it and other fields of science are fuzzy. Humans might like firm, delineated boundaries between things,but nature isn’t so picky.

Astronomers

Who are we? What do we do? I used to look through telescopes for a living,or at least study the data that came from detectors strapped onto them. But now they talk and write (and make videos) about astronomy, and relegate my viewing to their personal backyard telescope. But they still consider themself an astronomer, so that should give you an idea that there’s a lot of wiggle room in the profession. Doing the observations fit the physicalmodel of how stars blow up, or how galaxies form, or the way gas flows through space?Well, one better know the maths and physics, because that’s how we test the hypotheses. And someone who does that is generally called an astrophysicist.

Of course, the telescopes and detectors don’t create themselves. We need engineers to design and build them and technicians touse them. Most astronomers don’t actually use thetelescopes themselves anymore; someone who’s trained in their specific use does that forthem. Some of those instruments go into space, andsome go to other worlds, like the moon and Mars. We need astronomers and engineers andsoftware programmers who can build those, too. And then, at the end of all this, we need people to tell you all about it. Teachers, professors, writers, video makers, even artists. So they'll tell you what: If you have an interestin the Universe, if you love to look up at the stars, if you crave to understand what’s going on literally over your head, then who am I to say you’re not an astronomer?

However you define astronomy, humans have been looking up at the sky for as long as we’ve been humans. Certainly ancient people noticed the big glowy ball in the sky, and how it lit everything up while it was up, and how it got dark when it was gone. The other, fainter glowy thing tried, but wasn’t quite as good as lighting up the night. They probably took that sort of thing pretty seriously. They probably also noticed that when certain stars appeared in the sky, the weather started getting warmer and the days longer, and when other starswere seen, the weather would get colder and daytime shorten.

And when humans settled down, discovered agriculture,and started farming, noticing those patterns in the sky would have had an even greater impact. It told them when to plant seeds, and when to harvest. The cycles in the sky became pretty important. So important that it wasn’t hard to imagine gods up there, looking down on us weak andridiculous humans, interfering with our lives. Surely if the stars tell us when to plant,and control the weather, seasons, and the length of the day, they control our lives too… and astrology was born. Astrology literally means “study of the stars”; as a word it’s been used before science became a formal method of studying nature. It irks a bit, since it got the good name, and now we’re stuck with “astronomy,”which means “law or culture of the stars." That’s not really what it is!