How do scientists know that white holes don’t exist?
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answers:
Phillip say: all this talk of black holes, white holes dark matter, etc is really a strain on the grey matter.
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Damir say: well they haven't discovered any in real life yet
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Ilse say: how do they know green holes dont exist?
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Sherwood Forrester say: "Know" is a pernicious term. They don't "know" that white holes don't exist. They just haven't observed one, and while they're mathematically not impossible, there's not a good theoretical reason to expect to find any.
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Ronald 7 say: Because they have never found one
The only Theoretical White Hole that could have been imagined was the Big Bang
You have as much chance of finding a Unicorn
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Adullah M say: Do exist but can not be seen of their so intense radiant beyond the eyes could see.
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Jeffrey K say: Nobody has ever seen a white hole. But we don't know for sure that they don't exist. Quasars or gamma ray bursts might be white holes. Or maybe they are hidden behind event horizons.
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say: We don't know, we just haven't found one.
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neb say: No one can really prove they don’t exist. They are predicted in various solutions of general relativity because of the time symmetry of general relativity. White holes appear as time reversed black holes.
The problem with exact solutions of general relativity is that they are not realistic. For instance, the simple white hole solutions for Schwarzschild black holes require that the black hole is eternal - or starts at a singularity. A stellar black hole, one formed from gravitational collapse of a massive star, does not meet that criteria. The time dependent process of collapsing ‘pinches’ off the white hole region. Many of the other exact black black hole solutions, such as a Kerr black hole, predict a lot of weird stuff not likely to exist in reality, such as a Cauchy horizon where predictability of the future from the past no longer exists. The Cauchy horizon is likely to be unstable though. Same is true for wormhole metrics (with certain caveats). The bottom line is that much of the exotic predictions of general relativity are not physically realizable.
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ann say: Dunno. Define a white hole.
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oneofmagi@rocketmail.com say: Somebodies said warm hole in their novels of SF.
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drake say: They don’t have evidence they do exist
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Rowan say: No light can escape a black hole, except maybe for the jets that come out either side, which aren't actually from the thing itself, but from subatomic particles that get caught in the magnetic field as they get crushed to pieces falling into it. It doesn't make any sense, and there's no reason to think there is white holes.
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cosmo say: There are no plausible examples in the actual sky.
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Jon say: They don't know that. They just haven't found a way that one might form naturally.
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