The Speed of Light

It was a planet - a planet vastly different from earth. It had no air, no water, and was just about as inhospitable as you can get. But it was inhabited just the same.

The colony was average size, about 6000 people, mostly engineers, but some children, and some adults who supported the engineers. They had no interest in terraforming, or making the place any more comfortable than it was. They were there purely for the resources the planet had to offer; which were mined, or 'harvested'. Resources such as iron, which came down in molten raindrops from the clouds, were collected and solidified into huge balls the size of moons, and flung back to earth.

This planet was 5000 light years away, and it took 5036 years to get there, but nobody on the transport ship cared, as they slept all the way there. Some slept soundly, and others had nightmares, and died, but it was in the bounds of normal attrition.

Generations passed, and production started.

The mining colony was a great success.

But a lot of things can happen in 10000 years.

The last thing the people on earth saw was a comet, made of metal, the size of a moon.