This has gotten a lot of attention in media that we nerds pay attention to, but not much elsewhere. Last week something blew up deep in space.
If you’d been looking up at the sky at that time, you’d have set several records. You’d have seen the furthest naked-eye-visible object. Seven and a half billion light years away, this explosion happened long before our Earth was even formed. The light from it has been travelling that long just to reach us. It’s five thousand times farther away than the previous most-distant visible thing, which is an entire galaxy.
What does five thousand times mean? Imagine something really small, maybe the fine print on your credit card statement, something you have to hold a foot away from your face to read. Then imagine being able to read it from a mile away. Your credit rating would probably be higher.
It was also the most intrinsically bright thing ever recorded. Supernovas had been the brightest seen so far, in their brief life outshining their entire host galaxies. This was two-and-a-half million times brighter than the brightest supernova. If that supernova were the luminosity of a single firefly, this would be a medium-sized searchlight.
It’s a good thing it was so far away. Were it to happen really close to us — say 100 light years — would blow away the atmosphere and begin to melt the surface of the Earth. Even at 6000 light years, it would cause mass extinctions.
For all we know, one has already happened; we’re just waiting for news to get here.