The world is a crazy place. Unexpected things happen all the time, and while I may plan to be around to have the Important Conversations with my kids, I could get hit by a bus tomorrow. Or today. I could choke to death on the ham sandwich I make for lunch. These things happen.
There are things I want my kids to understand about me — what I think about the Big Questions like life and death and religion and Faster Than Light Travel and why it’s important that Han shot Greedo first. I hope I get the chance to have those conversations, but maybe I won’t, so I’m going to write them some letters.
And I figure I’ll put them up here, so there are as many redundant copies as possible.
What I Think About Space and Traveling Faster than the Speed of Light
I think you’re probably going to be around me long enough to know that I like science (and science fiction) stuff that has to do with space. There are lots of reasons for this, and many (maybe even most) of them have to do with the fact that I think space is pretty amazing. The way the planets move through the solar system, the way the solar system moves through the galaxy, and the way the galaxy moves through the universe — it’s all pretty awesome. The universe is very big — “vast” is the word that lots of people like to use — and while that can be pretty scary to some people (sort of the way it can be scary to stand on top of a really tall building and look down), it can also be exciting, because there’s so much to see. People have been on the Earth for a pretty long time and we still haven’t figured out or learned everything to there is to know about this world; and there are so many more worlds out there, full of things to learn, that we will probably never run out.
Think about that: there will always be something new to learn, for the rest of time. I think that’s a very good thing.
(I’d hate to know everything — I’d get bored.)
But there is something that comes up when people talk about space that I wanted to write about. It’s called Faster Than Light travel, which is what people call flying in a spaceship from one planet to another at a speed faster than the fastest thing we know about in the whole universe: light.
There are a couple reasons people talk about faster than light travel, and I wanted to explain them.
Reason #1: Space is Big
I know I already said this, but I think I need to give an example, because I didn’t really understand how big ‘big’ was until someone gave me an example, so let’s talk about just the solar system and how big that is.
I know you’ve probably studied it in school, and while I’m very proud of the model you made with all the planets and the sun, it might make you think that the solar system will fit onto one big piece of white cardboard, and that isn’t quite true, so we’re going to make a model of the solar system in our head.
First, we need a sun. The sun on the model you made for school was probably about the size of a baseball, so we’ll use that: take a baseball and put it out in our front yard. That’s our sun.
Now we’re going to walk out to where the Earth would be in our little model. To do that, you have to take about ten giant, dad-sized steps down the sidewalk on the way to the mailbox, then stop. Look back at the baseball. That’s how far the sun is from the earth. Now look down at the sidewalk. See if you can find a grain of sand down there. That’s how big the Earth is, compared to the baseball sun.
If we wanted to walk out to Pluto at the edge of our model solar system, we’d have to walk three blocks down the street. If you looked back, and the trees weren’t in the way, you probably couldn’t even see the baseball anymore (unless someone held it up for you, and it would be hard to see even then). While you’re all the way out there, don’t bother looking for Pluto — it’s much smaller than our sand-grain Earth.
And if, on your three-block walk, you spotted a fairly small marble lying in the gutter, that would be Jupiter, but you probably won’t see it, because that marble could be two-and-a-half blocks from our baseball sun in any direction — not just the direction we walked.
Space is REALLY Big
If you wanted to stay in this model of the solar system that we made and walk to the closest star from our sun, that would be Alpha Centauri. To keep everything kind of close to the right distance away, we would have to get another baseball and mail it to Aunt Barbara out in New York, and then you’d have to walk from our house to hers. (That’s actually not quite far enough away, but to make it far enough away we’d have to swim out into the ocean after our baseball for about a hundred miles, and I don’t want to do that, so let’s just say it’s at Aunt Barbara’s.)
Reason #2: We Travel Really Slow
Let’s say we actually wanted to walk all the way to Aunt Barbara’s house to visit the Alpha Centauri baseball. People all walk different speeds, but if you’re a grown up, and you’re in pretty good shape, and you have enough food, and the weather stays nice, it would probably take you about two and a half months to walk that distance. That’s something like 15 or 20 miles of walking a day.
And that might seem like it would take a really long time, but if we actually could fly to Alpha Centauri in two-and-a-half months, scientists would be pretty amazed, because that’s MUCH faster than it takes light to get to the real Alpha Centauri, and light is the fastest thing we know about. If you were traveling at the same speed as the speed of light, it would take you about four and a half years to walk to Aunt Barbara’s house, because you could only walk a little less than two miles every day. (And that doesn’t mean that light is slow — light is not just fast, it’s fastest — it’s that space is so big.)
And four and a half years is how long it would take light.
We aren’t nearly as fast as light.
In fact, if we walked to the Alpha Centauri baseball at Aunt Barbara’s house at the same speed as the fastest ship we’ve ever sent out into space, it would take us seventy thousand years to get there, which would be like only taking about nine giant, dad-sized steps every day. It would hardly seem like moving at all.
Reason #3: We Really Want to Go to Other Worlds
I kind of tricked you — I said there were only two reasons, but this one is also pretty important. The thing about other worlds and other stars is that when we get to thinking about them, we get really excited and we want to go see them. Humans like to touch things, to make sure that they’re real and see how they feel, and there’s probably always going to be a part of us that won’t really believe in something until we can hold it.
And that’s probably the biggest thing that makes science fiction writers (and scientists) write things about faster than light travel: we really want it to be possible, because if it isn’t (and it probably isn’t), that means we will never get to go visit other stars in person.
That’s the important thing I hope you understand, because it’s easy to get confused about this if you see me reading a book or watching a movie or playing a game where the heroes are flying from planet to planet in a few seconds; you might think that something like that is possible, or at least that I believe it’s possible.
I think that for as many lifetimes as our brains can really imagine, humans are going to live on Earth (and maybe a few of the other planets and moons in our solar system), simply because it’s impossible for us to get anywhere else. I think faster than light travel is kind of like fairies and ghosts and dragons — something that’s fun to read about, or something I’ll use in a story when I need something kind of special or magical to happen, but not something that exists in any kind of useful or useable way.
Now I’m going to tell you why that doesn’t matter to me, and why I think it’s important for scientists to keep studying space and other stars and planets.
Staring at the Stars
There are a lot of stars in the galaxy that are close enough for us to get a pretty good look at with the telescopes we have today, and every couple years our ability to look out into the galaxy gets better — we get better at seeing things, we get better at figuring out what it is we’re looking at, and that tells us more and more about the galaxy, which turns around and tells us more about our own world, and about us.
Right now, we’re getting to the point where we can really start to tell if there are any planets around other stars that are like Earth; the kind of planets that the life that we understand would grow. In a few years, we’ll probably even be able to tell that about the moons around big planets like our own Jupiter. That’s going to be an incredibly interesting and exciting time.
But what do I mean when I say it will tell us something about us?
Well, I live on Earth. If I want to, I can tell you how the air smells, and how bright the sky is today, and how cloudy it is; how warm, how cold, and how windy. I can tell you about the birds I see flying around, or the prairie dogs looking at me out of their burrows as I drive home, or how great it is to see you smile when I pick you up from school. I’m not a scientist, but I’m kind of an expert on some parts of the Earth.
One thing I don’t know, though, is if there’s anything else out there in the whole universe like us, and that would be a kind of amazing thing to know, I think, no matter what the answer is.
Imagine if you and your family lived on an island in the middle of the ocean, too far away to travel to any other islands. Now imagine if you knew for sure that you were the only people on any of the islands in the whole ocean — think about how special and amazing you would feel — also, think about how much better you might treat that island that you’re on if you knew that it was the only island you were ever going to get, and if you screwed up your island there wouldn’t be anyone else on any other island to keep going. You might feel kind of lonely in the great big ocean, all by yourself, but at least (maybe) you’d have a purpose.
Now imagine the other answer: if you knew for sure that lots of other islands had people on them. Maybe not people (at all) like you, but still living people who are going through the same kind of island-experiences as you. You will never meet them, and you’ll probably never really even get to talk to them, but just knowing that they’re out there would make you (well, me) feel like part of a much bigger Thing than anything we (I) have ever been a part of. People aren’t so good at being part of all the living things on Earth, but maybe we’d be better at being part of the living things Everywhere. For me, at least, that would be a pretty amazing feeling too. Maybe we’d feel less ‘special’, but we might not feel so alone.
(Also, maybe we’d act better if we knew other people were watching. I know that works on me when I’m at the movies.)
But of Course That Isn’t All of It
Even if we weren’t able to find out about other living things on other worlds, and even knowing that we’ll never travel anywhere but here, I still think that studying the stars and planets beyond our own is important simply because right now, it is one of the only ways in which we (people) look for knowledge just because it’s out there. No company is going to make a billion dollars if we find out there’s life on one of Jupiter’s moons; no one is going to win an election if we find an underground lake on Mars. When we look out at the stars, we are (almost always) looking just to look; just to learn.
We are looking just because there is Stuff We Don’t Know out there, and We Want to Know It.
That wanting to know things — that desire to understand everything that isn’t us — is (I think) one of the best parts about people. I think it’s the thing that makes us people, and it’s maybe the thing that helps make us better people.
You probably won’t hear me use that word very often, so I’ll tell you that it means “better than we usually are”, which is a pretty good thing to be.
We will probably never fly to another star at speeds faster than the speed of light — doing that is probably impossible, and even if it isn’t, it’s so far past the science that we understand today that the only way we can even imagine it happening is with silly-but-fun things like warp drives and hyperspace drives and jump drives and all kinds of magic wands that people like me bolt lights and buttons onto until they look like machinery — but that doesn’t matter.
I don’t think it’s about traveling to other stars. It’s about understanding them (and us) better.
And that’s always worth it.
Love you, kiddo.