This is an image of a thing that happens that is both very fast and also invisible. The colorful blocks are representations of “fast radio bursts” (FRBs) which are sudden surges of radio waves that come from outside our galaxy, so from unimaginably far distances away. These have been detected by a telescope called the “Australian SKA Pathfinder,” or ASKAP (the “SKA” doesn’t stand for music with a backbeat, but “Square Kilometer Array”). They only last a few milliseconds but there are thousands of them every day. No one’s sure exactly what causes them, either, although they let off as much energy in one millisecond as the Sun does in 10,000 years. They’re not from supermassive black holes, not from exploding stars, and not from cosmic strings. Maybe from big, heavy stars colliding?
The step-like pattern between different colors shows how different frequencies of energy in the same burst arrive at slightly different intervals, which means they’re (basically) touching different kinds of otherwise undetectable matter, like gas and dust. The radio bursts then give us a way to see stuff that’s not visible any other way, out in the voids between galaxies.
You can read more about the 2020 research into FRBs here, at Sci-News. The image came from ICRAR and CSIRO/Alex Cherney.