So now the Mods are getting heavy-handed? The religion topic is tangentially related. Did the thread owner complain?

So now the Mods are getting heavy-handed? The religion topic is tangentially related. Did the thread owner complain?

The OP is about black holes, ID has steered it towards faith and you've continued the discussion in that way. A reminder of what the original topic is about isn't heavy handed but your soap opera dramatic response is.

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So now the Mods are getting heavy-handed? The religion topic is tangentially related. Did the thread owner complain?

The OP is about black holes, ID has steered it towards faith and you've continued the discussion in that way. A reminder of what the original topic is about isn't heavy handed but your soap opera dramatic response is.

And again I ask if the OP has complained? I'm not being dramatic. I'm asking if you guys are applying the rules as Fred has put forth. I've also outlined how the discussion is tangentially related too. If you guys are going to keep issuing warnings for things that should be considered OK, then I would say it is heavy handed.

... getting heavy...

Following on from various assumptions that I've had lingering for eons, thanks to this thread a good answer was thus stumbled upon:

See:

"can a black hole collapse until it gets smaller than its Schwarzschild radius?"


Not such a clever question but one of the answers looks to be spot on with present ideas:

... General Relativity tells us that time passes more slowly in an intense gravitational field (from the point of view of someone in a less intense region of the field). This has been verified experimentally on a small scale.

Imagine you're near (but not too near) a black hole, in communication with a probe that's dropping into it. As you observe an analog clock on the probe, you'll see its second hand moving more and more slowly as the probe approaches the event horizon, coming closer and closer to a dead stop.

You'll never actually see the probe reach the event horizon; time on the probe, as seen from an outside vantage point, will come arbitrarily close to the moment it reaches it, but it will never actually get there.

The same thing happens to any matter falling into a black hole. It will quickly reach a point where you can no longer see it, but it will never quite reach the actual event horizon.

Inside the event horizon, time passes infinitely slowly (again, this is all from an outside point of view). So once the event horizon forms during the initial collapse that forms the black hole, nothing further happens inside it. Everything inside the event horizon is frozen in time, and cannot collapse any further.

On the other hand, from the point of view of the probe itself (say, if you foolishly volunteered to ride along), local time continues to pass at its normal rate of 1 second per second. You'll pass through the event horizon, and if the black hole is massive enough for the tidal stress at that point to be manageable, you might not even notice. You might see events, including further collapse, continue to occur after you're inside. But if you look back as you're falling, you'll see time in the outside universe pass more and more quickly, and just as you cross the event horizon you'll see eternity pass in a finite amount of time. So from the point of view of a hypothetical observer who's fallen into a black hole, yes, the body that formed the black hole can continue to collapse -- but any such observer might as well be outside the universe, since there's no way to communicate with them.

All this is based on relativity, ignoring quantum mechanics. Current theory (see Hawking radiation) says that quantum effects cause black holes to evaporate. All information about anything that fell into the black hole is lost (i.e., this isn't a way for you to escape after you've fallen in), but all the mass/energy will eventually come out as random radiation. This happens in a finite amount of time from the point of view of an outside observer -- which means that if you're riding the probe, the black hole will evaporate just as you're crossing the event horizon. (You will not survive the experience.)...



So... A "black hole", also known originally as a "frozen star" for being apparently frozen in our timeframe, can be expected to evaporate away back into our universe before enduring long enough to collapse all the way to a 'singularity' "nothingness".


Which comes to a follow-on question... (Geee, ain't Science fantastic for exploding horizons[*]! :-) )

As a black hole evaporates, could it suffer an explosive expansion for some point where gravity no longer overwhelms the nuclear forces?

Keep searchin',
Martin


*: Science can be described as expanding [further out] our horizon of ignorance as we come to learn more to better appreciate how much more there is that we do not yet know...

ps: Apologies for the multiple puns in the apt choice of words... ;-)

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Event horizon.

http://en.wikipedia.org/wiki/Event_horizon

This question

"can a black hole collapse until it gets smaller than its Schwarzschild radius?"

would appear to be based on erroneous information.

One definition of a black hole is,
An object that is smaller than its Schwarzschild radius.

Therefore can it be described as a black hole if it hasn't yet collapsed below its Schwarzschild radius?

... So... A "black hole", also known originally as a "frozen star" for being apparently frozen in our timeframe, can be expected to evaporate away back into our universe before enduring long enough to collapse all the way to a 'singularity' "nothingness".


Which comes to a follow-on question... (Geee, ain't Science fantastic for exploding horizons[*]! :-) )

As a black hole evaporates, could it suffer an explosive expansion for some point where gravity no longer overwhelms the nuclear forces?

AND ANOTHER question!

So... for a collapsed rotating black hole... How can we see it continue to rotate if time for it has apparently slowed down to near zero for our timeframe?...

Does this suggest we should see a black hole slow down its rotation as it collapses further due to time dilation? (As opposed to speeding up due to conservation of angular momentum and conservation of energy?)


Keep searchin',
Martin


*: Science can be described as expanding [further out] our horizon of ignorance as we come to learn more to better appreciate how much more there is that we do not yet know...

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See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)

Hawking radiation is inversely proportional to the size of the black hole, so as it gets smaller it evaporates faster. I think they have to be microscopic before they go pop. It takes trillions of years for a medium sized one to go away.

According to classical theory the singularity has no structure, it is just infinite density with zero size. It's not highly compressed matter that can re-expand. If there is a singularity. I mean, due to time dilation the singularity will take infinite time to form, so no black hole that exists can have a singularity. I think?

As for rotation, it's like the mass. The singularity is infinitely small, spinning infinitely fast. It's a zero multiplied by infinity type situation, which in math is a classical undefined situation. That's what they mean by physics breaking down. Sometimes you can find a limit in a situation like that, which in this case must work out to the angular momentum.

Hawking radiation poses new questions

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Now wait a second, didn't you all just postulate that nothing can ever fall into a black hole? So how can Hawking radiation work? Doesn't one half of the particle - anti-particle pair have to fall into the hole for it to work?

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Oh dear, he's back... Playing troll discussion games rather than discussing the ideas...

Now wait a second, didn't you all just postulate that nothing can ever fall into a black hole?

Nope, noone here has postulated that at all.

So how can Hawking radiation work?

As described in the article. It's Quantum ;-)

Ask your cat? :-)

Doesn't one half of the particle - anti-particle pair have to fall into the hole for it to work?

Yes as in the two particles remain separated due to the gravity gradient.


(Note the likely confusion over 'particles' vs 'energy fluctuations'... An analogous effect is the Casimir effect across a similar scale. For the example of straddling across an 'event horizon', the effect is a game of probabilities.)


Keep searchin',
Martin

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http://en.wikipedia.org/wiki/Chandrasekar_limit

Related to white dwarfs, not black holes.

Still, a beginning point to start with perhaps.

Both a white dwarf as well as a neutron star possesses physical characteristics in their central cores which is not readily visible on the surface of these objects.

Again, I am not a mathematician or a physicist, but some knowledge about astronomy I still do have.

Oh dear, he's back... Playing troll discussion games rather than discussing the ideas...

Now wait a second, didn't you all just postulate that nothing can ever fall into a black hole?

Nope, noone here has postulated that at all.

http://setiathome.berkeley.edu/forum_thread.php?id=69611&postid=1410585

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Oh dear, he's back... Playing troll discussion games rather than discussing the ideas...

Now wait a second, didn't you all just postulate that nothing can ever fall into a black hole?

Nope, noone here has postulated that at all.

http://setiathome.berkeley.edu/forum_thread.php?id=69611&postid=1410585

So, the usual silly word games from you.

Now, please read my post you've so kindly linked to. Engage understanding and appropriate context. Gain inspiration.


No useful discussion from you there. Kindly move along. We haven't the time to waste on your silly word games. Cue suitable Monty Python phrase... (Not uttered because we are supposedly discussing Science in a Science forum.)

Keep searchin',
Martin

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See new freedom: Mageia Linux
Take a look for yourself: Linux Format
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Ask your cat? :-)

Lol!

Not a bad idea, actually...

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http://en.wikipedia.org/wiki/Neutron_stars

Supposedly they are spinning.

As close as you can get except for the black hole itself.

Oh dear, he's back... Playing troll discussion games rather than discussing the ideas...

Now wait a second, didn't you all just postulate that nothing can ever fall into a black hole?

Nope, noone here has postulated that at all.

http://setiathome.berkeley.edu/forum_thread.php?id=69611&postid=1410585

So, the usual silly word games from you.

Now, please read my post you've so kindly linked to. Engage understanding and appropriate context. Gain inspiration.

Couldn't be more plain ...
ML1 wrote:

Just as infalling material slows to near everlasting time from our viewpoint as they approach the event horizon

Go back to you math class and look up limits. You have said it slows to zero, at least that is the plain meaning of your words. If it is zero how does it cross inside as it must for Hawking radiation to exist?

You has made a very common mistake. One that several other posters here have said as well, implying that something never vanishes from our universe as it falls into a black hole. That is not true. It does vanish in a finite time.

Now if you are smart you will be able to post what is in error in your original statement.

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A black hole is defined by its surface being the Schwarchild radius and its central core being the singularity.

The closest we get to explain the laws inside a black hole relates to either Einstein's Special and/or General law of Relativity (at least when it comes to the notion of time) and possibly Quantum Theory when it comes to the relationship between matter and energy.

We assume that fusion processes takes place in the core or center of our sun because hydrogen, being compressed to a metallic composition because of enormous pressure and the heat which ensues is being fused to helium, releasing about 4% of the mass being used for this into energy because two atoms of helium are slightly less in weight than four atoms of hydrogen.

Because our sun is an ordinary star, this energy is being emitted or released from the sun by means of radiation, something we are thinking of as being particles - anything from radiowaves through gammarays and X-rays.

Black holes are rather dead or deceased stars which no longer are having an energy production on their own. Heat may of course be present inside such objects, but energy is not actively being produced. At least for a neutron star, try putting a billion tons of sugar into a matchbox and have yourself included. You would not feel so very comfortable inside.

Inside such a black hole only mass and gravity is present. Time and energy has long gone. Time is related to our notion of dimensions which is meaning space as well as being able to assume that one single thing may not be able to occur two times "simultaneously" at two different places of "time".

A black hole may appear to be analogous or synonymous with Einstein's laws of General Theory / Quantum Theory even though the notion of time ceases to exist. It is gravity itself which is the main reason for the existence and properties of a black hole, not mass alone. Gravity may still be aasumed to be related to the principle or notion of energy. I wonder whether Einstein ever was able to explain gravity on it own.

Couldn't be more plain ...
ML1 wrote:

Just as infalling material slows to near everlasting time from our viewpoint as they approach the event horizon

Go back to you math class and look up limits. You have said it slows to zero, at least that is the plain meaning of your words. If it is zero how does it cross inside as it must for Hawking radiation to exist?

So... Your usual twist of context and befuddlement to twist the words into an argument divorced from reality. All in the style of a corrupt lawyer...

Please prove your maths credentials... Then again, please don't wast our time. Enough of your insults and slurs. Just as for a black hole, don't feed the troll...


For those actually interested in what we understand of reality, the context trick being played by our troll is that:

Infalling material has to approach the event horizon, and so fall through a gravity and time gradient. From our viewpoint, we never see any material actually make it across the event horizon due to time appearing to slow down for that material. From the viewpoint of the material, time appears to continue as normal at a normal rate except that the rest of the universe rapidly races ever faster towards eternity.

However...

In contrast, the "zero point energy" for Hawking radiation is already there as part of the very 'fabric' of space. The pairs of 'particles' spontaneously created suffer a finite separation and so have a finite chance that near or at the event horizon, one of the pair of particles is denied the chance to recombine with its partner particle. Hence there is an energy imbalance that in effect bleeds energy away from the event horizon...

And the Hawking radiation suggests the black hole will evaporate at the 'instant' just as any infalling material sees itself about to reach the 'inside'.


Keep searchin',
Martin

---

See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)

Couldn't be more plain ...
ML1 wrote:

Just as infalling material slows to near everlasting time from our viewpoint as they approach the event horizon

Go back to you math class and look up limits. You have said it slows to zero, at least that is the plain meaning of your words. If it is zero how does it cross inside as it must for Hawking radiation to exist?

So... Your usual twist of context and befuddlement to twist the words into an argument divorced from reality. All in the style of a corrupt lawyer...

If you actually want to know your error, ask nicely.

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