Some black holes bring dead “zombie” stars back to life just to rip them apart later

In the cosmic world of seduction, black holes earn the scintillating title of being the dames of doom. Scientists at the Lawrence Livermore National Laboratory in California have detailed a fascinating connection between dead white dwarf stars and black holes, and found that the latter could bring “zombie” stars back to life just to destroy them.

Supercomputer simulations provided images of this deadly romance. Midsize black holes (objects between 100 times the mass of our sun to those thousands or even billions of times the mass of our sun) have just enough gravitational force to reignite a dead white dwarf star — a stellar corpse that has used up all of its nuclear fuel. It’s the “Goldilocks theory” applied to space science; with this perfectly sized black hole having just the right amount of energy to cause stellar material in the dead star to fuse into varying amounts of calcium and iron. This chain reaction would produce more fusion as the star got closer to the black hole. And then, just as the black hole’s “lips” caress the star, the corpse would be reignited.

Interestingly, the star’s revival would create powerful electromagnetic waves that would be detectable by our technology. This means that astronomers would be able to “see” where this reanimation happened and find the medium-sized black hole responsible for this nucleosynthesis process.

That said — the necromancing black hole would only bring the star back to life just to rip it apart later.

“As [the spherical star] approaches the black hole, tidal forces begin to compress the star in a direction perpendicular to the orbital plane, reigniting it,” explained physicist Rob Hoffman, co-author of the study. “But within the orbital plane, these gravitational forces stretch the star and tear it apart.”

Findings of this study were published in the September 2018 issue of The Astrophysics Journal.

Paint it black

A black hole is a cosmic object that contains incredible amounts of gravity within a relatively small place that not even light can get out. This usually occurs as a star dies. Because no light can get out, black holes — despite their name — are invisible. Astronomers use special tools to see how stars that are very close to black holes behave differently than other stars.

Albert Einstein first predicted black holes back in 1916 as he conceptualized the general theory of relativity. However, the term “black hole” was only coined and used in 1967 by American astronomer John Wheeler. Not long after, in 1971, the first black hole was discovered.

There are three types of black holes: primordial black holes, which can range from the size of a single atom to a mountain and are considered “small” by space standards; stellar black holes, which are the ones that are most often found, and are are usually 20 times bigger than our sun; and supermassive black holes, which are at least a million times heavier than our sun.

Despite popular media portraying a vacuum-like activity of black holes, these stellar objects do not “suck” planets or other material. Stars just fall into them. If a star passes too close to a black hole, it is torn apart. (Related: Astronomers have, for the first time, detected matter falling into a black hole at 30% of the speed of light.)

On a different but similar note, physicists have recently debunked a long-standing theory about what would happen if a person were to fall into a black hole. It was believed that a human would be stretched out like spaghetti until they reached the single point in space-time where the mass of the black hole is concentrated (called the “singularity”) where they would be completely obliterated. However, a 2012 study in Nature concluded that the quantum effects found in the outer layer of the black hole would act like a wall of fire, instantly burning anyone to death.

Sources include:

LiveScience.com

NASA.gov

CBC.ca

Space.com