Bad Astronomy. Misconceptions and Misuses Revealed, from Astrology to the Moon Landing 'Hoax'

meters in any direction because smoke blocks your vision. You have no idea what shape the room is; it might be a circle, or a square, or a pentagram. You don’t even know how big it is! It could have walls just a meter beyond your vision, or it could stretch halfway to the Moon. You can’t tell just by looking. But no matter how big or what shape, the room will look like it is about 20 meters in radius and centered smack dab on you.

That was Kapteyn’s problem. Because he could only see out to a few hundred light-years before gas and dust blocked his view, he thought the Milky Way, which was then considered to be the whole universe, centered on us. However, observations by another astronomer, Harlow Shapley, in 1917 revealed that we are not at the center of the Milky Way, but indeed displaced quite a bit from the center.

Do you see the pattern? First the Earth was the center of everything — hurrah! Then, well, ahem. Maybe the Sun still is — yay! But then, yikes, actually we’re way out in the suburbs of the Galaxy. Well, this was getting downright insulting.

But the worst humiliation was yet to come. Kapteyn’s universe, as it was called, was about to collapse. Or, more aptly, explode.

Observations by Edwin Hubble, after whom the space telescope is named, showed that our Milky Way galaxy was just one of thousands and perhaps millions of other galaxies. What was thought to be the whole universe was really only just a single island of stars floating in space. Instead of being at the center of everything, we were just another face in the crowd.

When Hubble analyzed the light given off by these other galaxies, he got what may be considered the single biggest surprise ever sprung on a scientist. He found that almost all these myriad galaxies were rushing away from us. It was as if we were a cosmic pariah, and everything else in the universe was falling all over itself trying to get away from us.

Make no mistake: this is really weird, and completely unexpected. The universe was thought to be static, unchanging. Yet Hubble found that it’s on the move. It’s hard to underestimate the impact of these observations. And there was more: Hubble found that not only were galaxies all rushing away from us, but also the ones farther away were moving faster than the ones near us. The tools of the time didn’t let him look at galaxies that were terribly far away, but more recently, as bigger and more sensitive telescopes have come on line, we have found that Hubble was right. The farther away a galaxy is, the faster it appears to recede from us.

It didn’t take long for people to realize that this was characteristic of an explosion. If you blow up a bomb, then take a snapshot of the explosion a few seconds later, you see how shrapnel that’s farther from the center must be moving faster. The fastest bits move the most in a given time, while slower bits haven’t moved out as far.

This implies that the universe started in a gigantic explosion. You can think of it this way: if all the galaxies are moving away from us as time goes on, then they must have been closer in the past. If you reverse time’s arrow and let it run backwards, there must have been a time in the past when everything in the universe was crushed into a single point. Let time run forward again, and BANG! everything is set in motion.

And what a big bang it was, starting up the universe and sending it flying. Could this be right? Did the universe start out as a single point that exploded outwards? Perhaps no single scientific theory has stirred people, incited their anger, their confusion and, indeed, their awe more than the Big Bang theory. I suspect that even Darwin’s observations on evolution may have to take back seat to the biggest bang of them all.

But it does have one comforting aspect: it says we are at the center, because everything is rushing away from us…

…or does it? Let’s use an analogy. Imagine you are sitting in a movie theater, and the seats are packed together so closely that they are touching. Furthermore, the seats are all on movable tracks. I hit a button, and suddenly every seat moves so that there is now one meter separating each chair. Your nearest neighbors are all one meter away, in front of you, behind you, on your left, and on your right. The next seats over are all two meters away, and the next ones from those are three meters away, and so on. But wait! That’s true for any seat in the house. If you got up and moved into a seat a couple of rows up, and we repeated this experiment, you would see exactly the same thing. The next seats over would be one meter away, and the ones past that would be two meters away, and so forth.

So no matter where you sit, it looks like all the seats are rushing away from you. It doesn’t matter if you are actually in the center seat or not!

Also, the seats farthest away from you appear to be moving the fastest. The seats next to you moved one meter when I hit the button, but the next ones moved two meters, and so on. Again, no matter where you sit, you’d see the same thing: it looks like all seats are moving away, and that the ones that are farther away move the fastest.

That is exactly what Hubble found. Shakespeare said, “All the world’s a stage,” not realizing that, in a way, all the universe is a movie theater. Scientists studying Hubble’s observations quickly realized that the universal expansion may be real, but it gives the illusion that we are at the center, when we may not be at the center at all.

And if that’s not weird enough, the universe still has some tricks up its sleeve.

With stuff this bizarre going on, it’s no surprise to find Einstein lurking somewhere nearby. Einstein was busily pondering the universe in the years before Hubble’s shocking discoveries. He was applying some pretty hairy math to the problem, and came across a difficulty. The universe, he discovered, should not be here. Or, more precisely, that something was supporting it against its own gravity. Left to itself, the universe’s gravity would cause all the galaxies to attract each other, and the universe would quickly collapse like a souffle after the oven door is slammed. Before Hubble, remember, it was thought that the universe was unchanging. Something must be counteracting gravity, so Einstein decided to add a constant to his equation that would be a sort of antigravity. He didn’t know what it was, exactly, but he figured it had to be there.

Or so he thought. When he found out along with the rest of the world that the universe was expanding, he realized that the expansion itself would counteract gravity, and he didn’t need his cosmological constant. He discarded it, calling it “the biggest blunder of my life.”

It’s too bad, really. As astronomer Bob Kirshner once pointed out to me, given what Einstein knew at the time, he could have actually predicted the expansion of the universe. Why, he’d have been famous!

Anyway, what Einstein came to understand in later years is that the universe is a peculiar place. First, he realized that space is a thing. What that means is, it was always thought that space was just a place in which stuff existed, but space had no real presence itself. It was just space. But Einstein saw that space was a tangible thing, like a fabric into which the universe was woven. Gravity could distort that fabric, bending space itself. A massive object like a planet or a star (or, on a smaller but no less real a scale, a lobster or a toothbrush or a nail) warps space.

A common analogy compares our three-dimensional space to a two-dimensional rubber sheet. Stretched out, that sheet represents space. If you roll a tennis ball across it, the ball will move in a straight line. But if you put, say, a bowling ball on it, the sheet will get a funnel-shaped depression. If you then roll the tennis ball near the bowling ball, the path of the tennis ball will bend, curving around the bowling ball. That’s what happens in the real universe: a massive object warps space, and the path of an object will bend when it gets near it. That warping is what we call gravity.

If space is itself a thing, then it’s possible for space to have a shape. Indeed, the mathematics of cosmology strongly imply that space has some sort of shape to it. It’s hard for us mere humans to wrap our brains around such a concept, so once again the two-dimensional analogy is pretty useful.

Imagine you are an ant, and you live on a flat sheet that extends infinitely in every direction. To you, there is no up or down; all there is is forward, back, left, and right. If you start walking, you can walk forever and always get farther from where you started.

But now I’m going to play a trick on you. I take you off the sheet and put you on a basketball. You can still only move in back or forth, ahead or back. But now, if you start walking straight, eventually you’ll get back to where you started. Surprise! If you have a good grasp of geometry, you might realize that maybe your two-dimensional space is only a part of another, higher dimension. Furthermore, you can guess a bit about the shape of your space because your walk returned you to your starting point. That kind of space is closed, because it curves back onto itself. There is a boundary to it; it’s finite.

Open space would be one that curves the other way, away from itself, so it takes on a saddle shape. If you