Stephen
Hawking has a new idea. The physicist and cosmologist was stated that black
hole does not exist in the universe. In the description of his ideas are
currently signed in scientific publication server arXiv, Hawking states that
nothing in the universe except a gray hole. If the black hole has an event
horizon where any has no escape even for light, gray hole has any apparent
horizon where only held temporarily. Hawking’s idea is controversial. But, how
can Hawking says a black hole does not exist? What is the reason?
Nature
article explained that the idea of Hawking actually intended to resolve
problems in astrophysics, called a black hole paradox fire wall. The problem
has been discussed by physicist at least in the last two years. Joseph
Plochinski from Kavli Institute is the person who coined the paradox. The
paradox arises from the simple question, what if the astronaut falls into a
black hole, what would happen?
According to
Einstein's theory of relativity, the astronauts will pass through the event
horizon, or "limit" black hole, into the black hole and stretched
like spaghetti before being destroyed. However, based on quantum mechanics,
applies to objects subatomic level, it happened differently. Event horizon
would be transformed into a high-energy region, called a firewall or a wall of
fire, which would make astronauts crisp like chips. To resolve that problem,
Hawking then got the idea that black hole does not exist, or rather no event
horizon. "The absence of a black hole event horizon means nothing, in the
understanding that light can not run indefinitely," Hawking said in its
publication. Instead of the concept of the event horizon, Hawking introduces
what he calls the apparent horizon. Event horizon and the apparent horizon have
equation, where in when the light was about to run out of the black hole will
be retained in the horizon.
However, they
also have differences. If they absorb more material, the event horizon will
grow larger than the apparent horizon. Apparent horizon does not trap and
destroy the material forever, but hold it temporarily. Material, light, and the
information is not lost, can emerge again through radiation. Don Page, an
astrophysicist at the University of Alberta, Canada, said that the new idea may
not be able to finish the Hawking paradox firewall and can even lead to new
problems. According to Page, the idea of Hawking allows for an extreme scenario
in which "everything is in principle able to get out of the black hole”. Apparent
horizon can shrink and disappear. At that time, everything was stuck in a black
hole would come out.
In the new
scenario is based on the idea of Hawking, the material information is not lost,
but shaken, so that when released will be very different from before. Polchinski
himself said that he was skeptical of the idea of Hawking. According to him,
there can be no black hole without event horizon.