Black-out

The destiny of a dying world lay in another—a blue planet which could not control its own.
Old Thak watched fondly as the new telescope was being put into its place. He had been a long time persuading the elders to build this instrument, a duplicate of the one destroyed in the latest great war. It was as fine a telescope as Mars could produce, and only Thak's assurances that the work was of the greatest importance had secured him this luxury.
His project must succeed, he felt, glancing at his students. Like him, they were almost spherical in shape, with fine arm-like appendages ringing their middles. They were young and enthusiastic, and Thak believed they could revive the science of astronomy. He, the last astronomer of Mars, would teach them all he knew.
The overseer of the workers was disgusted. You waste our resources, Thak, he declared. You have taken two years of labor by dozens of workers, and for what? So that you may look at the sky!
Thak's tentacles purpled, a sign of irritation. You military men! he retorted. It was your kind, Mitfpa, that destroyed our civilization and reduced our race to a few hungry thousands. You have ruined progress and science forever. You have hastened the death of our race. Unless—
He waved through the open doorway, pointing out the early evening sky. Just rising over the horizon was a blue body that was of a dazzling brilliance, outshining all the other heavenly bodies. Thak's voice became emotional.
On that planet, he said, are civilized beings. They hold the only hope for the salvation of our race. We must work to contact them, as long as there is one of us to carry on!
What is this, Thak? Mitfpa demanded angrily. How can you say, old one, that people of intelligence live on the blue planet? You will tell me next that you have been there!
The soldier laughed scornfully, but Thak's voice was unruffled as he explained. This is no mere fancy of mine. These people have been signalling to us for some time. And when I signalled back by creating a network of space-warping lines through our entire power system, they strengthened their signals. Then came your war—