Ten million years ago, some massive stars close to our own solar system blew themselves to bits. These exploding stars carved a big bubble in space and filled it with superhot gas. And today, our solar system is plowing through that bubble — a peanut-shaped region that’s about 300 light-years long. By earthly standards, the space between the stars is a hard vacuum — there’s just not much there. But there are a few atoms and molecules, known collectively as the interstellar medium. Shock waves from the exploding stars swept away most of the material around them. So the interstellar medium in this region, known as the Local Bubble, is especially thin — no more than a few percent as dense as the typical stretch of interstellar space. But it’s also especially hot, with its gas heated to a million degrees. As the bubble expands, it may squeeze denser clouds of gas and dust around it. Eventually, the clouds could break up into smaller clumps, which could collapse to form new stars. And those
