The Sound of Thunder

Suns fled and ten million moons fled after them. “Good God,” said Eckels. “Every hunter that ever lived would envy us today. This makes Africa seem like Illinois.” The Machine slowed; its scream fell to a murmur. The Machine stopped.

The sun stopped in the sky.

The fog that had enveloped the Machine blew away and they were in an old time, a very old time indeed, three hunters and two Safari Heads with their blue metal guns across their knees.

“Christ isn't born yet,” said Travis. “Moses has not gone to the mountain to talk with God. The Pyramids are still in the earth, waiting to be cut out and put up. Remember that, Alexander, Caesar, Napoleon, Hitler, none of them exists.” The men nodded.

“That” Mr. Travis pointed” is the jungle of sixty million two thousand and fifty-five years before President Keith.” He indicated a metal path that struck off into green wilderness, over steaming swamp, among giant ferns and palms.

“And that,” he said, “is the Path, laid by Time Safari for your use. It floats six inches above the earth. Doesn't touch so much as one grass blade, flower, or tree. It's an antigravity metal. Its purpose is to keep you from touching this world of the past in any way. Stay on the Path. Don't go off it. I repeat. Don't go off. For any reason! If you fall off, there's a penalty. And don't shoot any animal we don't okay.” “Why?” asked Eckels.

They sat in the ancient wilderness. Far birds' cries blew on a wind, and the smell of tar and an old salt sea, moist grasses, and flowers the colour of blood.

“We don't want to change the Future. We don't belong here in the Past. The government doesn't like us here. We have to pay big graft to keep our franchise. A Time Machine is damn finicky business. Not knowing it, we might kill an important animal, a small bird, a roach, a flower even, thus destroying an important link in a growing species.” “That's not clear,” said Eckels.

“All right,” Travis continued, “say we accidentally kill one mouse here. That means all the future families of this one particular mouse are destroyed, right?” “Right.” “And all the families of the families of that one mouse!

With a stamp of your foot, you annihilate first one, then a dozen, then a thousand, a million, a billion possible mice” “So they're dead,” said Eckels. “So what?” “So what?” Travis snorted quietly. “Well, what about the foxes that'll need those mice to survive? For want of ten mice, a fox dies. For want of ten foxes, a lion starves. For want of a lion, all manner of insects, vultures, infinite billions of life forms are thrown into chaos and destruction.

Eventually it all boils down to this: fifty-nine million years later, a cave man, one of a dozen on the entire world, goes hunting wild boar or saber-tooth tiger for food. But you, friend, have stepped on all the tigers in that region. By stepping on one single mouse. So the cave man starves. And the cave man, please note, is not just any expendable man, no I He is an entire future nation. From his loins would have sprung ten sons. From their loins one hundred sons, and thus onward to a civilisation. Destroy this one man, and you destroy a race, a people, an entire history of life. It is comparable to slaying some of Adam's grandchildren. The stomp of your foot, on one mouse, could start an earthquake, the effects of which could shake our earth and destinies down through Time, to their very foundations. With the death of that one cave man, a billion others yet unborn are throttled in the womb. Perhaps Rome never rises on its seven hills. Perhaps Europe is forever a dark forest, and only Asia waxes healthy and teeming. Step on a mouse and you crush the Pyramids. Step on a mouse and you leave your print, like a Grand Canyon, across Eternity. Queen Elizabeth might never be born, Washington might not cross the Delaware, there might never be a United States at all.

So be careful. Stay on the Path, Never step off!” “I see,” said Eckels. “Then it wouldn't pay for us even to touch the grass?” “Correct. Crushing certain plants could add up infinitesimally.

A little error here would multiply in sixty million years, all out of proportion. Of course maybe our theory is wrong. Maybe Time can't be changed by us. Or maybe it can be changed only in little subtle ways. A dead mouse here makes an insect imbalance there, a population disproportion later, a bad harvest further on, a depression, mass starvation, and, finally, a change in social temperament in far-flung countries. Something much more subtle, like that.