"It must have been a great city in its day," said Caroline softly. "I wonder what has happened to the people.”
"Died off," said Gary, "or left for some other planet, maybe for some other sun.”
The telescopic screen mirrored scene after scene of desolation. Vast deserts with shifting dunes and mile after mile of nothing but shimmering sand, without a trace of vegetation. Worn-down hills with boulder-strewn slopes and wind-twisted trees and shrubs making their last stand against the encroachment of a hostile environment.
Gary turned the ship toward the night side of the planet, and it was then they saw the Moon. Vast, filling almost a twelfth of the sky, it loomed over the horizon, a monstrous orange ball in full phase.
"How pretty!" gasped Caroline.
"Pretty and dangerous," said Gary.
It must be approaching Roche's limit, he thought. Falling out of the sky, year after year it had drawn closer to the Earth. When it reached a certain limit, it would be disrupted, torn to bits by the stresses of gravitation hauling and tugging at it. It would shatter into tiny fragments and those fragments would take up independent orbits around old Earth, giving her in miniature the rings of Saturn. But the same forces which would tear the Moon to bits would shake up the Earth, giving rise to volcanic action, world-shattering earthquakes, monstrous tidal waves. Mountains would be leveled, new continents raised. Earth's face would be changed once again, as it probably had been changed many times before. As it had been changed since early Man had known it, for search as he might, Gary could find no single recognizable feature, not a single sea or continent that seemed familiar.
He reflected on the changes that must have come to pass. The Earth must have slowed down. Probably a night now was almost a month long, and a day equally as long. Long scorching days and endless frigid nights. Century after century, with the moon tides braking the Earth's motion, with the addition of mass due to falling meteors, Earth had lost her energy.
Increase of mass and loss of energy had slowed her spin, had shoved her farther and farther away from the Sun, pushing her out and into the frigidness of space. And now she was losing her atmosphere. Her gravity was weakening and the precious gases were slowly being stripped from her. Rock weathering also would have absorbed some of the oxygen.
"Look!" cried Caroline.