What's Outside The Universe?

Grandson Bailey,

When we last saw you, you asked me what was beyond the edge of the Universe, and I didn't have a very good answer. To be honest, I felt like a baseball player that had practiced and practiced (I've read a lot of books and thought a lot about the same question myself), but suddenly I was standing in the outfield and a high fly ball was headed my way (your question)...and I dropped the ball.


Your question is a really good one and a very hard one to answer because the ideas aren't simple and they aren't easy to understand--even for me. But I've been thinking about what you asked, and I'm really, really glad you did because it made me think hard about the question again too.

Next time we see each other, maybe we can talk about this more, but here's my answer: think about the earth. It's a big ball, and when you look toward the horizon it looks like you can see where the earth stops. But you know from driving and flying that there's no edge. You travel for a while and you see past the horizon. And what do you see? More dirt, more trees, more roads, more mountains. There really isn't an edge at all. What's over the horizon? More of the same. That's the way it is when you look out into space. If you traveled a billion miles (which would only get you to about Saturn, still in our solar system) what would you see? More space, more stars, more galaxies.

But now think of this . . . you're a bug inside a balloon. You can't crawl outside because you can only live inside. A giant is blowing the balloon up, bigger and bigger. As the bug, you can see the inside of the balloon and, smart little bug that you are, you say to yourself, "I wonder what's outside?" Same idea as wondering what's outside the Universe, right?

We're kinda like bugs too, really smart ones. We have satellites and instruments and scientists that have done experiments that show the universe (which is kinda like our balloon) is expanding, and there's nothing outside -- there is no outside. But we can wonder.

Another way to think about this, and I know it's silly, is to ask, "What color is your name?" It doesn't make sense for a name to be a color in the same way it doesn't make sense for there to be something outside the universe. The universe is everything there is, and the idea that there's anything outside it just doesn't make sense.

Mind you, that doesn't mean it's not a good thing to think about and to ask questions about, because it makes us think in different ways. "What if I wrote my name with a red crayon? Wouldn't my name be red?" It sure would! So now we know that there are other ways to look at a question that might let us learn something new.

Think about flying straight north, over Canada, still north past the Arctic Circle, north more to the North Pole. Now ask yourself, can I go further north from here? No, there's no such thing as north of the North Pole. "Ah," you say, "but what if I go straight up?" Brilliant! That's not north, of course, but it does add an interesting new dimension to the problem if you'll pardon the pun.

Another way of thing about the universe might be, "Could there be other universes?" Maybe it doesn't make sense to ask what's outside our universe, but maybe it does make sense to ask if there could be other universes.

In fact, some people today think there are other universes. One idea is that there is an infinite number of other universes. Every time you do something there might be a universe where you don't do it. Did you drop your cookie and the dog got it? Don't worry, in another universe you didn't drop it. And in another universe, you dropped it, but the dog didn't get it so you could eat it anyway. And in another universe the dog got it, but he gave it back to you. In another universe Dr. Schrodinger's cat gobbled it up . . . or not.

WEIRD STUFF, HUH?

Even though we may not know the answer to all this yet, the important thing is that we keep asking questions and we keep looking for answers and we keep doing experiments to see if our ideas make sense. If someone tells you they have the answer to something, anything (sorry Mom and Dad) ask, "Why?" If they can't give you evidence, if they say it's just because they said so—or just because someone else said so—don't accept the answer until you, yourself, are satisfied the answer is right. And be prepared, be willing, to change what you think if new answers come along that show what you used to think is true isn't anymore. That's what learning is all about.

But be careful. There are some people that say we should always reject every answer to every question--but that would be a huge waste of time. There are some things such as gravity, and electromagnetism, and evolution that are so well understood that it's simply a waste of time to argue that they aren't accurate descriptions of reality. It wouldn't make much sense to study the idea that the Earth is held up by turtles instead of gravity, now would it?

I know this isn't a simple (or a short) answer. But you'll find there are very few of those in life.

Grandpa Tom

P.S. Now here's a question for you: you want to go swimming and your Mom say you can go, but you can only go halfway to the pool and then you have to ask again. She promises she'll always say yes. But remember you have to ask again after you get halfway to the pool. Will you ever get to swim? Seems like if you go halfway, and halfway, and halfway, and halfway you'll never get there. What do you think?