Although we have learned a lot about black holes over the recent years, one of the biggest mysteries that haunts physicists is the question of whether anything can escape them; and if so, how?
A new study headed by scientists from around the world - including the University of Alberta and Kyoto University - seeks to answer this question by examining black hole "firewalls," which refer to the barriers that some physicists believe black holes possess. These barriers are believed to instantly incinerate any matter that falls into them.
The biggest problem surrounding black hole firewalls is the fact that they don't fit with older black hole theories that physicists are not eager to part with.
In order to describe a black hole, you need both Einstein's theory of general relativity and quantum mechanics, two theories that conflict with each other. To make things even more complicated, the firewall theory pits both of these opposing theories against one another.
Raphael Bousso, a string theorist, said in 2013 that the black hole firewall "shakes the foundations of what most of us believed about black holes. It essentially pits quantum mechanics against general relativity, without giving us any clues as to which direction to go next."
While quantum mechanics suggests the existence of black hole firewalls, the idea of them violates a major tenant of Einstein's theory of relativity. If free-falling in a black hole is the same as in floating in empty space, as the Einstein's theory predicts, this would be impossible if the object falling through the black hole is incinerated by a firewall.
The new study suggests that if firewalls exist, they are not limited to one place inside black holes, instead possessing the ability to reach beyond their edges into regions that can be observed outside of the black hole.
"If a firewall exists, not only would an in-falling object be destroyed by it, but the destruction could be visible, even from the outside," said Misao Sasaki, a researcher from Kyoto University and co-author of the paper.
As of now, research on the existence of black hole firewalls is inconclusive and the two theories of quantum mechanics and general relativity will continue to battle it out until more is revealed.
The findings were published on April 7 on the pre-print server arXiv.
