The man who proved Stephen Hawking wrong | Hacker News Reader

The man who proved Stephen Hawking wrong

telegraph.co.uk

47 pointsColinWright17 comments

Stephen Hawking wasn't "wrong", it was a theory. Theories aren't nessacarily what's actually going on, it's just a way of viewing a problem in a way that helps you predict outcomes. People who say things like "this theory is wrong" are the same typ of people who say "scientists say" or "science says". Susskind simply came up with a theory that is less wrong, and that will spark new conversations and one day someone will come up with a theory that's less wrong than his.

As far as I know, Juan Maldacena's paper is what what finally convicted Stephen Hawking that he was wrong. Then "black hole complementarity" argument become good enough to explain back hole paradox. Then it came Joe Polchinski with his AMPS paper which proved that "complimentary black hole" is wrong.

Now we are in square one - and it could be Hawking is right.

(I have only basic physic knowledge so I would appreciate if somebody with more education can describe this).

What do you mean we are in square one ? Could you point to some article ? As much as I'm not a physicist I like reading about this :-). Thanks

How can matter fall into a black hole? Time will stop upon getting closer to the horizon so matter will virtually just sit there. After some time black hole will look more like a bubble, won't it?

I remember asking on stack exchange and I've got an answer that no, it doesn't actually fall in.

Time from that matter's perspective. From the outside observer's perspective, it zips right in.

Same way that if you travel near the speed of light your perception of time slows until you are no longer traveling that fast. But to an outside observer you are zipping right along.

Nope, the other way around. From matter's perspective, its time ticks as ever. But for outside observer, it just halted there.

At some point, the matter goes past the event horizon. Then the notion of outside observer stops having any meaning. Before that, known clocks in that matter slowed down for an outsider, and the outsider's clock went faster from that matter's perspective.

No - think about the experience from the POV of a photon. To a photon, it arrives in the same frame of time as it left, and it doesn't experience time at all. Meanwhile, the an outside observer, they see light move from source to target.

If I'm correct you are suggesting that the external observer "sees" the object falling inside whilst the object itself perceives time as frozen. This is wrong, as far as I know. The proper time in the free-falling frame of reference ticks in the usual manner, and it is quite easy to compute the time it takes the object to fall inside a black hole (the textbook computation being usually done for an object which has zero velocity at infinity). The external observer on the other hand will see the falling object to slow down and the wavelength of the object's emitted photons to be redshifted by an infinite factor as it approaches the event horizon, so the object will disappear before crossing it. This is true both for massive and massless particles falling in. Also, to nitpick: thinking about massless particles i.e. objects moving at c has having frozen time is often misleading: the "usual" definition of proper time, i.e. the square root of time squared minus space squared is not a good parametrization for light-like geodesics.

Nope, skj had it right and you've got it backwards. Otherwise we wouldn't perceive black holes to be black holes...

If we observed matter falling into a black hole to be "halting there", well, we'd see it halted there on the spherical surface of the event horizon instead of what we actually see, which is that matter and light get completely sucked in.

"instead of what we actually see, which is that matter and light get completely sucked in"

We actually never see that

"Due to this effect, known as gravitational time dilation, an object falling into a black hole appears to slow down as it approaches the event horizon, taking an infinite time to reach it. At the same time, all processes on this object slow down, for a fixed outside observer, causing emitted light to appear redder and dimmer, an effect known as gravitational redshift. Eventually, at a point just before it reaches the event horizon, the falling object becomes so dim that it can no longer be seen." http://en.wikipedia.org/wiki/Black_hole

This is completely consistent with my statement :)

Our time perception of the object remains the same, but the processes experienced by the object itself are much slower, relative to how we perceive them.

Specifically, if the object falling in is emitting blue light, and let's say that the frequency of blue light is one per second for the sake of doing some arithmetic, then that object keeps emitting 1/second and looks blue to itself. But in our frame of reference, those 1/second actually become .1/second (its time is moving slower then our time), and appears red.

Could someone explain to me why matter falling into a black hole might imply that information would be annihilated?

It seems to me that the information is still present, though no longer accessible from outside the black hole. That doesn’t seem at odds with the preservation of information in any way.

I am not a physicist.

The problem comes from Hawking radiation. Over time, the matter/energy absorbed by black holes does get released through Hawking radiation. However, this emission contains no information about the matter that originally went into the black hole (it is entirely dependent on the mass, angular momentum, and charge of the black hole).

> Hawking made the stunning claim that material which falls into a black hole disappears forever. If correct, it would mean that the fundamental laws of the universe would have to be rewritten.

The 'hard' science physics seems to be one of the weakest sciences at all.

Any non-paywalled source?

https://archive.today/pcCwW

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