Rescue Party by Arthur C. Clarke (Astounding, May 1946) opens with an alien spaceship commander telling the crew of the S9000 that they are about to arrive at the third planet of the solar system ahead—and that they only have four hours to explore before its sun goes nova! We then find out why the aliens have so little time:
“You will wonder how such a disaster, the greatest of which we have any record, has been allowed to occur. On one point I can reassure you. The fault does not lie with the survey.
“As you know, with our present fleet of under twelve thousand ships, it is possible to re-examine each of the eight thousand million solar systems in the galaxy at intervals of about a million years. Most worlds change very little in so short a time as that.
“Less than four hundred thousand years ago, the survey ship S5060 examined the planets of the system we are approaching. It found intelligence on none of them, though the third planet was teeming with animal life and two other worlds had once been inhabited. The usual report was submitted and the system is due for its next examination in six hundred thousand years.
“It now appears that in the incredibly short period since the last survey, intelligent life has appeared in the system [and a] civilization that can generate electromagnetic waves and all that that implies [has existed for two hundred years].”
“As you know, Bob, [insert explanium or handwavium here].”
When the S9000 arrives in Earth’s atmosphere two hours later they find they are too late: there are no signs of life, and the wildfires that have raged across the planet are dying out (they have run out of fuel).
Two scout ships are dispatched to explore the planet anyway. The first finds a set of mirrors that appear to be transmitting TV signals out into the galaxy; then they find a deserted city, apparently abandoned by humans years earlier when they returned to the live in the countryside. On return to the S9000, the crew find that the other scout ship has not returned.
The second ship, meantime, has found a huge administrative centre (jam packed with filing cabinets full of computer punch cards!) Then, when they leave to return to the S9000, they spot a huge tunnel opening and quickly decide to explore it—only to find themselves trapped by closing subway doors, and whisked off in a train that eventually takes them under the ocean.
The third act of the story sees the S9000 follow the train and rescue the scout ship crew at the next station. As they get them back on board, the sun goes nova (the ship is hiding in the lee of the Earth and the aliens see the Moon light up). The S9000 accelerates towards light speed as they leave the system.
There is final section to the story which sees the aliens realise that the mirrors are sending video signals of the catastrophe in a particular direction. When the S9000 follows they eventually see a “great fleet” of human generation ships ahead.
The last paragraphs see one of the aliens say they feel rather afraid of the humans’ fleet, and another reply that they are a “very determined people”, and that they had better be polite to them as “we only outnumber them about a thousand million to one”.
I liked this well enough, but it’s basically an overlong story (the two scout ship accounts have needless overlap and duplication) about aliens wandering about on a depopulated Earth and getting themselves into trouble. The strongest parts are probably the astronomical setup (the nova, the ship hiding in the Earth’s shadow), the dying Earth descriptions, and the slingshot ending where they find the generation ships (although not the last line, “Twenty years afterward, the remark didn’t seem funny”, which seemed a rather dissonant and threatening expression of human exceptionalism).
*** (Good). 10,300 words. Story link.