That was why it was good to have Carl for a friend. No matter how sorry you got to feeling for yourself, he could usually snap you out of it one way or another. Right now, Doug thought, Carl was diligently at work with that peculiar brand of psychology that all newspapermen strive ceaselessly to acquire that makes people blab when they ought to keep quiet. But why not—Carl wouldn't know what the hell it was all about and he wouldn't care, if he thought it would take some of the pressure off.
"Well, listen then. Ever look through an observatory telescope and have somebody tell you you were focused on some star or other a couple of thousand light years away? Maybe it was in the process of blowing up and becoming a nova or something like that. Anyhow, it would be explained to you that you were seeing that star as it was two thousand years ago. You were seeing, for instance, an explosion that happened twenty centuries in the past. Reason, of course, is that it took the light that long to get from the star to you. More simply, the light that strikes your back porch in the morning left the sun about nine minutes before."
"Very clear. Only how come, if the universe is a closed form of infinity like it says in all the new books, this light never doubles back on itself—gives you two or even a million images of the same star?"
"That's where the tired light comes in. After a certain length of time—unthinkable aeons of it—it, like all other forms of energy, peters out. Runs down. Quits. Kaput. They call it entropy. It constitutes, actually, a gradual running down, growing old of the universe. As far as anyone knows, this happens before it 'doubles back' on itself, as you put it. You can't catch it coming around the second time to see what you looked like umpteenillion ages ago. So, if you want a second look at yourself, you've got to go out and catch the light which you reflected in the past—"
"Oh brother. You mean anybody on a planet, say, forty light years from Earth with a supertelescope looking at us would be watching the battle of Chateau Thierry and Belleau Wood! A hundred and eighty light years away he'd see us slugging it out against King George III at Saratoga and Valley Forge!"
"You've got it. In other words, the light reflected from Earth then is somewhere deep in Space now. If you could haul it in on some kind of a receiver, you could see everything all over again—you could watch the land masses of Earth as they shifted to form the continents as we know them today."
"You'd need something faster than light to trap the light itself—and I thought that was against Fitzgerald or somebody."
"If you followed the same space warps the light did, it would be. But if it were possible to operate your receiver through the fabric of space-time, instead of along it—a kind of short-cut—you might turn up with what you're after."
"I am sorry I got into this."
Blair smiled tiredly. "Me too. Hell, I'm fooling around with things I don't pretend to know anything about. Just enough to putter. Just enough to keep my mind off all-day-long. God knows what I'll get when I turn the damn thing on. Probably not even snow so I'm not worried. Turn left at the next stop-light—they've got that new cut-off finished." He started buttoning his coat. Grayson turned left as ordered.