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Author Topic: Black holes don't exist?  (Read 2854 times)

Offline oatman

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Black holes don't exist?
« on: 25/01/2015 10:34:22 »
Recently seen an article appear in a few tabloid papers describing research from a US scientist who claims to have proven mathematically that black holes cannot exist, that essentially the amount of radiation they expel would be too much.

Typically this was reported as fact with no opposing opinions, and haven't seen any other mention.

Would be interested for thoughts on this!


 

Offline JohnDuffield

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Re: Black holes don't exist?
« Reply #1 on: 25/01/2015 13:17:19 »
See some reportage here: Black holes do NOT exist and the Big Bang Theory is wrong.

IMHO Laura Mersini-Houghton was being deliberately sensational in order to promote herself. We can see that there's something very massive, and very small, and very black in the middle of our galaxy.


See http://astro.uchicago.edu/cosmus/projects/UCLA_GCG/

This is hard scientific evidence, whilst Hawking radiation remains hypothetical. Her assertions dismiss the former and treat the latter as fact.
 

Offline jccc

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Re: Black holes don't exist?
« Reply #2 on: 25/01/2015 22:11:16 »
That's photoshoped. A real hole in the bathroom sucks my poop every day.
« Last Edit: 26/01/2015 02:16:41 by jccc »
 

Offline JohnDuffield

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Re: Black holes don't exist?
« Reply #3 on: 25/01/2015 22:34:39 »
I know. But it's based on robust scientific evidence. See for example this IOP physicsworld article.
 

Offline yor_on

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Re: Black holes don't exist?
« Reply #4 on: 27/01/2015 14:06:15 »
Black Holes exist.

She says "But now Mersini-Houghton describes an entirely new scenario. She and Hawking both agree that as a star collapses under its own gravity, it produces Hawking radiation. However, in her new work, Mersini-Houghton shows that by giving off this radiation, the star also sheds mass. So much so that as it shrinks it no longer has the density to become a black hole.

Before a black hole can form, the dying star swells one last time and then explodes. A singularity never forms and neither does an event horizon. The take home message of her work is clear: there is no such thing as a black hole."

Whereupon Unruh counters.

"“The [paper] is nonsense,” Unruh said in an email to IFLS. “Attempts like this to show that black holes never form have a very long history, and this is only the latest. They all misunderstand Hawking radiation, and assume that matter behaves in ways that are completely implausible.”

According to Unruh, black holes don’t emit enough Hawking radiation to shrink the mass of the black hole down to where Mersini-Houghton claims in a timely manner. Instead, “it would take 10^53 (1 followed by 53 zeros) times the age of the universe to evaporate,” he explains.

“The standard behaviour by such people [who don’t understand Hawking radiation] is to project that outgoing energy back closer and closer to the horizon of the black hole, where its energy density gets larger and larger,” he continued. “Unfortunately explicit calculations of the energy density near the horizon show it is really, really small instead of being large-- Those calculations were already done in the 1970s. To call bad speculation "has been proven mathematically" is, shall we say, and overstatement.” "

And, well, as John points out, we need them to explains some otherwise very weird facts.
 

Offline oatman

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Re: Black holes don't exist?
« Reply #5 on: 30/01/2015 18:46:53 »
Thanks all, it's a shame papers report any new sensational scientific announcement as fact with no caveats/opposing opinions. I'm sure there are tons of people who now believe they don't exist!
 

Offline JohnDuffield

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Re: Black holes don't exist?
« Reply #6 on: 31/01/2015 15:29:31 »
This sort of thing happens quite a lot I'm afraid. There's an awful lot of bad science being hyped by wannabees fighting for a spot on the Discovery Channel.
 

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Re: Black holes don't exist?
« Reply #6 on: 31/01/2015 15:29:31 »

 

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