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

lived in open space, you could walk forever and never get back to where you started.

These three spaces — open, closed, and flat — have different properties. For example, if you remember your high school geometry, you’ll recall that if you measure the three inside angles of a triangle and added them together, you get 180 degrees. But that’s only if space is flat, like a page in this book. If you draw a triangle on the surface of a sphere and do the same thing, you’ll see that the angles always add up to more than 180 degrees!

Imagine: take a globe. Start at the north pole and draw a line straight down to the equator through Greenwich, England. Then go due west to, say, San Francisco. Now draw another line back up to the north pole. You’ve drawn a triangle, but each inside angle is 90 degrees, which adds up to 270 degrees, despite what your geometry teacher taught you. Actually, your teacher was just sticking with flat space; closed and open space can be quite different. In open space, the angles add up to less than 180 degrees.

So that ant, if it were smart enough, could actually try to figure out if its space is open, closed, or flat just by drawing triangles and carefully measuring their angles.

This is all well and good if you’re an ant, but what about us, in our three-dimensional space? Actually, the same principles apply. Since space itself is warped, it can take on one of these three shapes, also called geometries. And, just like the ant, you could try taking a walk to see if you come back to where you started. The problem is that space is awfully big, and even the fastest rocket we can imagine would take billions or even trillions of years to come back. Who has that kind of time?

There’s an easier way. Karl Friedrich Gauss was a nineteenth-century mathematician who worked out a lot of the math of the geometry of the universe. He actually tried to measure big triangles from three hilltops, but was unable to tell if the angles added up to more or less than 180 degrees.

There are still other ways. One is to look at incredibly distant objects and carefully observe their behavior. Using complicated physics, it’s possible to determine the universe’s geometry. At the moment, our best measurements show that the universe is flat. If it curves at all on large scales, it’s very difficult to see.

Now let’s imagine again that you’re an ant, back on the ball. As a fairly smart ant, you might ask yourself: If my universe is curved, where is the center? Can I go there and look at it?

The answer is no! Remember, you’re stuck on the surface of the ball, with no real concept of up or down. The center of the ball isn’t on the surface, it’s inside, removed into the third dimension, which you cannot access. You can search all you want, but you’ll never find the center, because it’s not in the universe as you know it.

The same can be said for own 3-D universe. If it has a center, it might not be in our universe at all, but in some higher dimension.

As it happens, even this might not be the case. Gauss showed mathematically that, as bizarre as it sounds, the universe can be curved without curving into anything. It just exists, and it’s curved, and that’s that. So it’s not that we are curved into the fourth dimension, if there is such a thing. The fourth dimension may not exist at all, and our universe simply may not have a center.

This is the worse humiliation of all. To be removed from the center of the universe is one thing, and it’s another to have it appear that we are at the center, only to realize that anywhere in the universe can make that claim. But then, to be told there isn’t any center at all is the ultimate insult.

Maybe in a way it’s the perfect equalizer. If we can’t occupy the center of everything, at least no one else can, either.

And yet we are still not done.

Einstein was just getting started when he realized that space was a tangible thing. Time, he found, was a quantity that in many ways was like space. In fact, space and time were so intertwined that the term space-time continuum was coined to describe the union.

He also realized that the moment of creation, the Big Bang, was more than just a simple (though all- encompassing) explosion. It was not an explosion in space, it was an explosion of space. Everything was created in the initial event, including space and time. So asking what there was before the Big Bang really has no meaning. It’s like asking, where was I before I was born? You were nowhere. You didn’t exist.

But time was created in the event as well. So asking what happened before the Big Bang is what we call an ill-posed question, another question with no meaning. The physicist Stephen Hawking likens it to asking, “What’s north of the north pole?” Nothing is! The question doesn’t even make sense.

We want it to make sense, because we are used to things happening in a sequence. I get up in the morning, I ride my bike to work, I make my coffee. What did I do before I woke up? I was sleeping. Before that? I got into bed, and so on. But face it, at some point there was a first event. In my case, it was a moment in January 1964, which probably happened because it was a cold night and my future parents decided to snuggle a bit.

But there was something even before that, and before that. Eventually, we run out of thats. There was a first moment, a first event. The Big Bang.

In television documentaries it’s very common to show an animation of the Big Bang as an explosion, a spherical fireball expanding into blackness. But that’s wrong! Since the explosion was the initial expansion of space itself, there isn’t anything for the universe to expand into. The universe is all there is. There is no outside, any more than there was a time before the Big Bang. What’s north of the north pole?

The illusion of living in a big expanding ball persists. I have a hard time shaking it myself. You would think that there was some direction to the center of the universe, and if you looked that way you’d see it. The problem is, the explosion is all around us. We are part of it, so it’s everywhere we look: the biggest movie theater of them all.

Still confused? That’s okay. I sometimes think even cosmologists get headaches trying to picture the fourth dimension and the curvature of space, though they’d never admit it. There’s an expression in astronomy: cosmologists are often wrong, but never unsure of themselves.

Yet we continue to try to understand this vast universe of ours. Maybe Albert himself put it best: “The most astonishing thing about the universe is that we can understand it at all.”

I cannot leave this topic without one final note. Historians studying medieval astronomy are beginning to come to the conclusion that, to the medieval astronomers, being at the center of the universe was not all that privileged a position to occupy. It was thought that all the detritus and other, um, waste products of the heavens fell to the center, making up the Earth. So instead of being an exalted position, the center of the universe was actually a rather filthy place to be. In the end, maybe not even having a center is better than the alternative.

Part IV Artificial Intelligence

People believe weird things.

There are people who believe the Earth is 6,000 years old. Some people believe that others can talk to the dead, that a horoscope can accurately guide your day, and that aliens are abducting as many as 800,000 people a year.

I believe weird things, too. I believe that a star can collapse, disappearing from the universe altogether. I believe that the universe itself started as a Big Bang, possibly as a leak in space and time from another, older universe. I believe that there is a vast reservoir of hundred-kilometer-wide chunks of ice hundreds of billions of kilometers out from the Sun, yet I have never seen one of these chunks in situ, nor has any other person on Earth.

So, what’s the difference? Why do I think it’s wrong to believe that the Earth is young when I believe in things I’ve never seen?