Millions of years in the distant future, a posthuman scientist is attempting to build a time machine and tests it by sending two boxes with a hastily gathered batch of educational toys into the past. When the boxes fails to return, he believes the entire experiment to be a failure, he discontinues his efforts. One box arrives in the middle of the 20th century and the second in the latter part of the 19th century. Both have had their time-travel circuitry irreparably damaged by the journey.
To upset the stable, mighty stream of time would probably take an enormous concentration of energy. And it's not to be expected that a man would get a second chance at life. But an atomic might accomplish both--
The real trouble with communications satellites is the enormous difficulty of repairing even the simplest little trouble. You need such a loooong screwdriver.
Earth has transformed overnight: The Gods and Goddesses of Ancient Greece and Rome have returned to Earth with all their awesome powers intact. War on any scale was outlawed, along with boom-and-bust economic cycles, and prudery but no change was more startling than the face of New York, where the Empire State Building has become the Tower of Zeus...
Stark terror ruled the Inner-Flight ship on that last Mars-Terra run. For the black-clad Leiters were on the prowl. and the grim red planet was not far behind. First published in 1954.
The Romantics used to say that the eyes were the windows of the Soul. A good Alien Xenologist might not put it quite so poetically. but he can, if he's sharp, read a lot in the look of an eye!