18 Years Later: A Supernova Lights Up the Radio
A supernova explosion is the death of a massive star, leaving behind a gas cloud. If there's plenty of hydrogen around, the shock wave spreads like an echo from a distant gunshot.
Molecular Fingerprint of a Hot Core
In an oven, a huge loaf of bread is baking. Inside the dough, there is a tiny, hottest spot: that's where the future loaf begins to rise. A hot molecular core (a region the size of the Solar System, where gas is heated to hundreds of degrees and compressed to billions of times the density of ordinary clouds) works in much the same way.