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Sat, 25 January 2014 13:19 |
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Originally posted by: GettingCloser
http://news.yahoo.com/blogs/sideshow/stephen-hawking-says-bl ack-holes-don-t-exist-012107567.html
Stephen Hawking says black holes dont exist
16 hours ago The Sideshow
Do black holes exist? Not exactly in the way we think says Stephen
Hawking (AFP)
Black holes are the source of endless fascination and speculation. Do
they hold the secrets of the universe and perhaps even the key to time
travel?
We may never know the answers to those questions because famed
theoretical physicist Stephen Hawking says black holes dont actually
exist. At least not in the way weve been taught to think about them.
"The absence of event horizons mean that there are no black holes in
the sense of regimes from which light can't escape to infinity,"
Hawking writes in a new paper entitled, "Information Preservation and
Weather Forecasting for Black Holes."
So, what does that mean exactly?
Well, what Hawking is saying is that he doesnt believe "event
horizons," gravitational traps from which even light cannot escape,
actually exist.
Its a mind-bending theory as New Scientist puts it, which ensures
the debate will continue 40 years after Hawking first brought the
concept of black holes to the public.
In his lecture Into a Black Hole, Hawking described how an event
horizon works:
Falling through the event horizon, is a bit like going over Niagara
Falls in a canoe. If you are above the falls, you can get away if you
paddle fast enough, but once you are over the edge, you are
lost.There's no way back. As you get nearer the falls, the current
gets faster. This means it pulls harder on the front of the canoe,
than the back. there's a danger that the canoe will be pulled apart.
It is the same with black holes.
But now, Hawking says event horizons dont exist. However, he does say
that apparent horizons could exist, meaning that light technically
could escape from the deep gravitational pull of a black hole. Put
simply, an apparent horizon would only temporarily hold light and
information, eventually releasing them back into space.
Though, eventually is a pretty relative term when were discussing
the nature of spacetime.
The picture Hawking gives sounds reasonable, Don Page, a physicist
and expert on black holes at the University of Alberta in Edmonton,
Canada told Nature. You could say that it is radical to propose
theres no event horizon. But these are highly quantum conditions, and
theres ambiguity about what space-time even is, let alone whether
there is a definite region that can be marked as an event horizon.
Still, that doesnt mean astronauts will be lining up to dive into a
black hole anytime soon. As Nature puts it, an apparent hoizon
wouldnt burn you to a crisp like an Event Horizon would but it
wouldnt leave you in good shape either. Any information or object
escaping from a black hole in this scenario would be pretty
scrambled in Hawkings own words.
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