You know black holes: huge, inescapable. Other than Ellen, there is probably no force more powerful in the universe. According to a new study from the Lawrence Livermore National Laboratory, black holes could possess the most unholy of powers. They might be able to bring the dead back to life—as long as the dead in question is a white dwarf.
White dwarfs are extremely dense stellar core remnants, the last evolutionary stage for smaller stars that cannot become neutrons as they die. They're called white dwarfs because they are so packed with thermal energy that they emit a faint glow. Very hot when they form, they gradually cool over time since they lack any way to sustain a reaction.
Scientists at LLNL wondered what would happen if a white dwarf came into with an intermediate-mass black hole—something smaller than a supermassive black hole but no less destructive. Using a supercomputer to run dozens of simulations, they concluded that, in the moments before the black hole ripped the white dwarf to shreds, the white dwarf could reignite into a proper star.
The process would work like this: The stellar matter would be fused into varying amounts of calcium and iron. This would create a form of . Given the black hole's unthinkably strong gravitational pull, tidal waves of movement would be triggered within the white dwarf as it stretched out to the black hole, sparking it back to life.
“The stretching phenomena can be very complicated,” says , coauthor on the paper. “Imagine a spherical star approaching a black hole. As it approaches the black hole, tidal forces begin to compress the star in a direction perpendicular to the orbital plane, reigniting it. But within the orbital plane, these gravitational forces stretch the star and tear it apart. It’s a competing effect.”
Intermediate black holes are still hypothetical. But if they do exist, scientists say, there would be no better coming-out party than a reignited star.
“It was exciting to see that the zombie star reignited in each of the close-encounter scenarios we looked at,” says Peter Anninos, the lead author on the LLNL paper. “But what really captured my imagination was the idea that these energetic events could be visible. If the stars align, so to speak, a zombie star could serve as a homing beacon for a never-before-detected class of black holes.”