Black Holes vs. Dark Stars
Scientists propose a controversial new theory: black holes can never form. From New Scientist:
Tanmay Vachaspati and his colleagues at Case Western Reserve University in Cleveland, Ohio, US, have tried to calculate what happens as a black hole is forming. Using an unusual mathematical approach called the functional Schrodinger equation, they follow a sphere of stuff as it collapses inwards, and predict what a distant observer would see.
They find that the gravity of the collapsing mass starts to disrupt the quantum vacuum, generating what they call “pre-Hawking” radiation. Losing that radiation reduces the total mass-energy of the object – so that it never gets dense enough to form an event horizon and a true black hole. “There are no such things”, Vachaspati told New Scientist. “There are only stars going toward being a black hole but not getting there.”
Goerge Chapline, a Lawrence Livermore physicist who isn’t mentioned in this article, proposed something similar (to my layman’s ear, at least) a few years ago (pdf). Interesting, but few theoretical physicists are buying Vachaspati’s math:
“I strongly disagree,” says Nobel laureate Gerard ‘t Hooft of Utrecht University in the Netherlands. “The process he describes can in no way produce enough radiation to make a black hole disappear as quickly as he is suggesting.” The horizon forms long before the hole can evaporate, ‘t Hooft told New Scientist.
Let’s hope it’s not true. Some of my favorite short stories and novels growing up involved back holes, singularities and event horizons.
