Astronomers have spotted the most distant and brightest "space laser" ever seen, and it's blasting from a galaxy collision that occurred when the universe was half its current age.
Here's a thought experiment. Imagine looking at Earth from a distant star system, armed with a powerful telescope capable of capturing its reflected light. Could you tell the planet was alive? The answer, remarkably, might be yes and the clue would come from the colour of the plants.

