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January 1994
March 1994

1994-02-01 »

Were we There Yet? or, Interstellar Travel: Where you Won't Be Any Time Soon

Our knowledge of "light" is a jungle of completely opposite opinions, all of which are correct at the same time. Scientists have determined that any object travelling faster than the speed of light will actually move backwards through time; on the other hand, the same scientists have also determined that no object can travel faster than the speed of light. If this is true, it does seem silly to even consider "warp speed" to be a viable means of transportation. But don't be fooled; there are some loopholes that make it plausible.

First, while travelling faster than the speed of light has been dismissed as impossible, it is still possible to travel at the speed of light. This has been demonstrated by light itself on various occasions in the past. How? I'll leave out the gory details, but it has been proven that light has no inertia. This means that, unlike everything else, it requires no energy at all to get moving, no energy to speed up, and no energy to slow it down and no energy stop it. (This, of course, explains why a car travelling at 60 km/h will kill you if it runs you over, and yet light, which travels noticeably faster, will just bounce off.) Since light requires no energy to accelerate, it can do so indefinitely without adding any energy. This, of course, leads to the question: why doesn't it go infinitely faster than it does? After much careful thought, scientists believe they have the answer.

Anything travelling at the speed of light is frozen in time. The general reaction to this statement is "Huh?" but with a bit of explanation it can be made clear. It all goes back to Einstein's theory of relativity: time is relative to the observer. Once again skimming over the details (which, it seems, only Einstein would understand), we discover that as an object accelerates, time slows down relative to that object. It seems that time and speed come together at - you guessed it - the speed of light. This is to say that a person riding a beam of light would be frozen in time - relative to everyone else, he could travel for several million years without aging a single second. To himself (since, relative to himself, he will always be stationary) time appears normal - it's just that the rest of the universe seems to be aging infinitely quickly!

Pretend you're an outside observer - one with very good eyesight. The man and the beam of light are travelling away from you at light speed and the man does not appear to be moving or aging at all in the meantime. After several million years, he reaches a far-off galaxy and dismounts his light beam. He's exactly as old as he was when he left, although you and your eyes have been buried for some time now.

What about the man on the light beam? Because time is stopped for him while he travels, it seems to him that he has arrived in no time at all (hence, he has travelled at infinite speed); the only problem is that everything is quite different than it was when he left. In fact, although he could fly back to Earth in an equally short time, our sun would probably have burnt itself out by the time he got back!

This, though, is an extreme case. For short trips, light speed is the way to go. Even if you miss four or five years, you won't feel like you have: you won't have spent money on hotels and restaurants, and the kids won't have complained even once. A perfect trip!

Unfortunately, there are also a number of problems inherent in fast-as-light travel. Firstly, if time is stopped, how do you know when it's time to get off? You don't; therefore, there has to be something already operating in "normal-time" to stop you. Secondly, since humans do have inertia, it's going to take at least some energy to get you up to that kind of speed. And, once you've reached that speed, it would be to your advantage not to crash into anything. Unlike light, which would simply bounce off, you might get hurt. Also, don't stay in hyperspace too long. A hundred-year trip won't hurt you much, but it's going to be awfully disappointing when you return home to discover that all your friends and family are long gone. With all these disadvantages, you can see how we have a bit of work ahead of us before this technology will become useful.

Yes, there are problems. No, we don't have any idea how to begin researching this incredible scientific oddity. And no, we still don't understand why it's even supposed to work. But it will work; it has to work - because Einstein said so. Someday soon, we'll be able to depart to destinations anywhere in the universe. Someday none-too-soon, we'll arrive at those destinations.

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