Read Online Farmer in the Sky by Robert A. Heinlein - Free Book Online Page B

That's what the Star Rover is going to do when it is finished.”
    One of the younger kids was waving his hand. “Mister Chief Engineer?”
    “Yes, son?”
    “Suppose it goes on a few weeks longer and passes the speed of light?”
    Mr. Ortega shook his head. “It can't.”
    “Why not, sir?”
    “Eh, how far have you gone in mathematics, sonny?”
    “Just through grammer school calculus,” the kid answered.
    'Tm afraid there is no use in trying to explain it, then. Just take it from me that the big brains are sure it can't be done.”
    I had worried about that very point more than once. Why can't you go faster than light? I know all that old double-talk about how the Einstein equations show that a speed faster than light is a meaningless quantity, like the weight of a song or the color of a sound, because it involves the square root of minus one—but all of that is just theory and if the course we had in history of science means anything at all, it means that scientists change their theories about as often as a snake changes his skin. I stuck up my hand.
    “Okay,” he says. “You with the cowlick. Speak up.”
    “Mr. Ortega, admitting that you can't pass the speed of light, what would happen if the Star Rover got up close to the speed of light—and then the Captain suddenly stepped the drive up to about six g and held it there?”
    “Why, it would— No, let's put it this way—” He broke off and grinned; it made him look real young. “See here, kid, don't ask me questions like that. I'm an engineer with hairy ears, not a mathematical physicist.” He looked thoughtful and added, “Truthfully, I don't know what would happen, but I would sure give a pretty to find out. Maybe we would find out what the square root of minus one looks like— from the inside.”
    He went on briskly, “Let's go on about the Mayflower. You probably know that when the original Star Rover failed to come back, the Mayflower was designed to be the Star Rover II, but the design was obsolete before they ever started putting her together. So they shifted the name over to the new intersteller ship, the Star Rover III, renamed this one the Mayflower and grabbed her for the colonial service.
    “You kids should consider how lucky you are. Up to now, emigrants to Ganymede have had to spend two years and nine months in space, just to get there. You're making it in two months.”
    “Couldn't we go faster?” somebody wanted to know.
    “We could,” he told us. “But we don't need to and it runs up the astrogation and control difficulties. In these new ships the power plant has gotten 'way ahead of the instrumentation. Be patient; your grandchildren will make the trip in a week, blasting at one g all the way. There'll be so many ships they'll have to have traffic cops and maybe we can come close to shipping out as many people as there are extras bom each year.
    “Enough about that,” he went on. “Who here can tell me what 'E equals M C squared' means?”
    I could have answered but I had already spoken up once and it doesn't do to get a reputation for apple polishing. Finally one of the older kids said, “It means that mass can be converted into energy.”
    “Right!” Mr. Ortega agreed. “The first real demonstration of that was the atom bomb they set off 'way back in 1945 at Alamogordo, New Mexico. That was a special case; they still didn't know how to control it; all they could do was to make one whale of a big bang. Then came the uranium power plants, but that still didn't amount to much because it was a very special case and only a microscopic percentage of the mass was converted into energy. It wasn't until Kilgore's energy transformation equations—don't worry about them; you'll study them when you are older if you are interested—it wasn't until Kilgore showed how it could be done that we had any idea of how to do what Dr. Einstein's energy-mass equation said, clear back in 1905.
    “And we still didn't know how to control