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Guest

Wed Aug 17, 2016 4:50 am   



On Wednesday, August 17, 2016 at 2:20:24 AM UTC+10, Tim Wescott wrote:
Quote:
On Tue, 16 Aug 2016 01:23:34 -0400, bitrex wrote:
On 08/16/2016 01:04 AM, rickman wrote:
I was explaining black holes to a friend who asked about the LHC and
thought about what might happen if a tiny black hole were created.

I believe matter falling into a microscopic black hole would still
enter it in a similar manner to large black holes elsewhere in the
universe by orbiting the tiny black hole while being accelerated
causing energy to be emitted before crossing the event horizon.

A microscopic black hole, if such a thing could exist, would radiate
itself away via Hawking radiation before it had much of a chance to do
anything.


https://en.wikipedia.org/wiki/
Micro_black_hole#Stability_of_a_micro_black_hole

If such a thing as Hawking radiation exists.


Hawking radiation is a very plausible hypothesis.

Quote:
There's still a lot we don't know about the border of relativity and
quantum mechanics, and it's on that border where Hawking radiation is
described. Most physicists _think_ that black holes evaporate, but no
one's observed it, and if our existing models are true then there ought
to be small black holes left over from the Big Bang, evaporating away
with an obvious radiation signature -- but we have seen no such signature..


If the small back holes didn't get Hoovered up by larger black holes - and every galaxy seems to have at least one large black hole.

The fact that we haven't seen anything radiating anything that looks like Hawking radiation isn't actually particularly convincing evidence that Hawking radiation doesn't happen, and everything else we know suggests that if black holes look anything like the way we think they do at the moment, they'd emit Hawking radiation.

The fact that LIGO has now picked up two black hole merger signals, from medium-sized black holes (a few solar masses) does point up the fact that black holes can merge, which might explain what might have happened to any small black holes left over from the Big Bang.

--
Bill Sloman, Sydney


Guest

Wed Aug 17, 2016 4:53 am   



On Wednesday, August 17, 2016 at 2:47:18 AM UTC+10, rickman wrote:
Quote:
On 8/16/2016 12:30 PM, George Herold wrote:
On Tuesday, August 16, 2016 at 12:20:24 PM UTC-4, Tim Wescott wrote:
On Tue, 16 Aug 2016 01:23:34 -0400, bitrex wrote:

On 08/16/2016 01:04 AM, rickman wrote:
I was explaining black holes to a friend who asked about the LHC and
thought about what might happen if a tiny black hole were created.

I believe matter falling into a microscopic black hole would still
enter it in a similar manner to large black holes elsewhere in the
universe by orbiting the tiny black hole while being accelerated
causing energy to be emitted before crossing the event horizon.

A microscopic black hole, if such a thing could exist, would radiate
itself away via Hawking radiation before it had much of a chance to do
anything.


https://en.wikipedia.org/wiki/
Micro_black_hole#Stability_of_a_micro_black_hole

If such a thing as Hawking radiation exists.
IIRC Hawking radiation mostly follows from thermo-dynamics.
It's like black body radiation... Black holes have some temperature.
(Finding the temperature of a black hole is the hard part... :^)

I'm not sure that is a valid way to look at it. Everything that makes
up a black hole is on the other side of the event horizon. It may well
have a temperature, but we'll never feel any effect from it as nothing
can cross back through the event horizon. In a sense, the event horizon
of a black hole is an infinite heat sink at 0 °K. There may be
radiation from the space around the black hole, but nothing from the
black hole itself.


Hawking's point was that Hawking radiation is a signal that comes from the event horizon. Black holes suddenly became a trifle less black, and there was a way of assigning a temperature to the black hole.

--
Bill Sloman, Sydney


Guest

Wed Aug 17, 2016 5:06 am   



On Wednesday, August 17, 2016 at 3:56:11 AM UTC+10, rickman wrote:
Quote:
On 8/16/2016 1:42 PM, George Herold wrote:
On Tuesday, August 16, 2016 at 12:47:18 PM UTC-4, rickman wrote:
On 8/16/2016 12:30 PM, George Herold wrote:
On Tuesday, August 16, 2016 at 12:20:24 PM UTC-4, Tim Wescott wrote:
On Tue, 16 Aug 2016 01:23:34 -0400, bitrex wrote:

On 08/16/2016 01:04 AM, rickman wrote:
I was explaining black holes to a friend who asked about the LHC and
thought about what might happen if a tiny black hole were created.

I believe matter falling into a microscopic black hole would still
enter it in a similar manner to large black holes elsewhere in the
universe by orbiting the tiny black hole while being accelerated
causing energy to be emitted before crossing the event horizon.

A microscopic black hole, if such a thing could exist, would radiate
itself away via Hawking radiation before it had much of a chance to do
anything.


https://en.wikipedia.org/wiki/
Micro_black_hole#Stability_of_a_micro_black_hole

If such a thing as Hawking radiation exists.
IIRC Hawking radiation mostly follows from thermo-dynamics.
It's like black body radiation... Black holes have some temperature.
(Finding the temperature of a black hole is the hard part... :^)

I'm not sure that is a valid way to look at it. Everything that makes
up a black hole is on the other side of the event horizon. It may well
have a temperature, but we'll never feel any effect from it as nothing
can cross back through the event horizon. In a sense, the event horizon
of a black hole is an infinite heat sink at 0 °K. There may be
radiation from the space around the black hole, but nothing from the
black hole itself.

--

Rick C

Ahh, Rick I understand you are a smart guy. There are plenty of other smart guys
out there. I think the best (clearest) explanation I've seen/ read
(and it's been a while) was in a set of video lectures by Leonard Susskind.
Googling he's got a bunch... I don't recall which ones. Advanced stat.. mech.
or maybe QM.

Black holes have a temperature. That's pretty cool. (NPI)
Here's wiki...(I only looked at the first few paragraphs.)
https://en.wikipedia.org/wiki/Hawking_radiation

Trouble is all of this is speculation and none is proven. I like a nice
mechanical explanation. Saying matter leaves a black hole by it
swallowing matter is not a very good argument. That's what Hawking
Radiation says.


That's not what Hawking radiation is about. As Dirac pointed out, the Heisenberg uncertainty principle means that virtual pairs of particles and anti-particles are always popping up everywhere and - mostly - vanishing again as they self-annihilate

http://www.universetoday.com/129471/what-are-virtual-particles/

If it happens at a back-hole event horizon, they can't self-annihilate.

A very pretty insight.

--
Bill Sloman, Sydney

bitrex
Guest

Wed Aug 17, 2016 5:51 am   



On 08/16/2016 05:34 PM, rickman wrote:
Quote:
On 8/16/2016 5:19 PM, Phil Hobbs wrote:
On 08/16/2016 04:40 PM, rickman wrote:
On 8/16/2016 2:39 PM, Phil Hobbs wrote:
On 08/16/2016 12:47 PM, rickman wrote:
On 8/16/2016 12:30 PM, George Herold wrote:
On Tuesday, August 16, 2016 at 12:20:24 PM UTC-4, Tim Wescott wrote:
On Tue, 16 Aug 2016 01:23:34 -0400, bitrex wrote:

On 08/16/2016 01:04 AM, rickman wrote:
I was explaining black holes to a friend who asked about the LHC
and
thought about what might happen if a tiny black hole were created.

I believe matter falling into a microscopic black hole would still
enter it in a similar manner to large black holes elsewhere in the
universe by orbiting the tiny black hole while being accelerated
causing energy to be emitted before crossing the event horizon.

A microscopic black hole, if such a thing could exist, would
radiate
itself away via Hawking radiation before it had much of a chance
to do
anything.


https://en.wikipedia.org/wiki/
Micro_black_hole#Stability_of_a_micro_black_hole

If such a thing as Hawking radiation exists.
IIRC Hawking radiation mostly follows from thermo-dynamics.
It's like black body radiation... Black holes have some temperature.
(Finding the temperature of a black hole is the hard part... :^)

I'm not sure that is a valid way to look at it. Everything that makes
up a black hole is on the other side of the event horizon. It may
well
have a temperature, but we'll never feel any effect from it as nothing
can cross back through the event horizon. In a sense, the event
horizon
of a black hole is an infinite heat sink at 0 °K. There may be
radiation from the space around the black hole, but nothing from the
black hole itself.

Hawking radiation is caused by half of a virtual particle-antiparticle
pair falling into the event horizon and the other half escaping.

Think about that. Matter falls into a black hole which leaves the black
hole with less matter?


No, the hole loses mass turning the virtual particle into a real one.

So a "virtual" particle has negative mass? The black hole captures one
virtual particle and the other becomes real. What exactly is the
difference between a virtual particle and a real one?


A virtual particle is "borrowing" energy from the uncertainty principle,
and then paying it back fast enough that nobody notices. In the language
of quantum mechanics, energy and time are non-commuting observables, in
the same way that position and momentum are.

A virtual particle becomes real when another thing gives the original
system enough energy to pay back the loan, without relying on quantum
subterfuge.

bitrex
Guest

Wed Aug 17, 2016 5:55 am   



On 08/16/2016 07:51 PM, bitrex wrote:
Quote:
On 08/16/2016 05:34 PM, rickman wrote:
On 8/16/2016 5:19 PM, Phil Hobbs wrote:
On 08/16/2016 04:40 PM, rickman wrote:
On 8/16/2016 2:39 PM, Phil Hobbs wrote:
On 08/16/2016 12:47 PM, rickman wrote:
On 8/16/2016 12:30 PM, George Herold wrote:
On Tuesday, August 16, 2016 at 12:20:24 PM UTC-4, Tim Wescott wrote:
On Tue, 16 Aug 2016 01:23:34 -0400, bitrex wrote:

On 08/16/2016 01:04 AM, rickman wrote:
I was explaining black holes to a friend who asked about the LHC
and
thought about what might happen if a tiny black hole were
created.

I believe matter falling into a microscopic black hole would
still
enter it in a similar manner to large black holes elsewhere in
the
universe by orbiting the tiny black hole while being accelerated
causing energy to be emitted before crossing the event horizon.

A microscopic black hole, if such a thing could exist, would
radiate
itself away via Hawking radiation before it had much of a chance
to do
anything.


https://en.wikipedia.org/wiki/
Micro_black_hole#Stability_of_a_micro_black_hole

If such a thing as Hawking radiation exists.
IIRC Hawking radiation mostly follows from thermo-dynamics.
It's like black body radiation... Black holes have some temperature.
(Finding the temperature of a black hole is the hard part... :^)

I'm not sure that is a valid way to look at it. Everything that
makes
up a black hole is on the other side of the event horizon. It may
well
have a temperature, but we'll never feel any effect from it as
nothing
can cross back through the event horizon. In a sense, the event
horizon
of a black hole is an infinite heat sink at 0 °K. There may be
radiation from the space around the black hole, but nothing from the
black hole itself.

Hawking radiation is caused by half of a virtual particle-antiparticle
pair falling into the event horizon and the other half escaping.

Think about that. Matter falls into a black hole which leaves the
black
hole with less matter?


No, the hole loses mass turning the virtual particle into a real one.

So a "virtual" particle has negative mass? The black hole captures one
virtual particle and the other becomes real. What exactly is the
difference between a virtual particle and a real one?

A virtual particle is "borrowing" energy from the uncertainty principle,
and then paying it back fast enough that nobody notices. In the language
of quantum mechanics, energy and time are non-commuting observables, in
the same way that position and momentum are.


That is to say, over very short timescales the actual energy density of
a region of spacetime is uncertain; uncertain enough such that random
particles pop in and out of existence since they don't really "know"
whether they should exist or not.

bitrex
Guest

Wed Aug 17, 2016 6:00 am   



On 08/16/2016 02:39 PM, Tim Wescott wrote:
Quote:
On Tue, 16 Aug 2016 12:50:57 -0400, bitrex wrote:

On 08/16/2016 12:20 PM, Tim Wescott wrote:
On Tue, 16 Aug 2016 01:23:34 -0400, bitrex wrote:

On 08/16/2016 01:04 AM, rickman wrote:
I was explaining black holes to a friend who asked about the LHC and
thought about what might happen if a tiny black hole were created.

I believe matter falling into a microscopic black hole would still
enter it in a similar manner to large black holes elsewhere in the
universe by orbiting the tiny black hole while being accelerated
causing energy to be emitted before crossing the event horizon.

A microscopic black hole, if such a thing could exist, would radiate
itself away via Hawking radiation before it had much of a chance to do
anything.


https://en.wikipedia.org/wiki/
Micro_black_hole#Stability_of_a_micro_black_hole

If such a thing as Hawking radiation exists.

It kind of has to, or else what we think we know about quantum field
theory must be pretty much wrong

The main question is not whether Hawking radiation exists, but what
happens to the information.

https://en.wikipedia.org/wiki/Black_hole_information_paradox

Well, true, and it probably does, but it hasn't been observed yet.

Quantum field theory doesn't predict either dark energy or dark matter,
yet astronomical measurements say they must exist. So quantum field
theory is kind of behind the 8-ball right now on explaining how the
universe works.


To my mind, a pretty interesting direction to head in would be to assume
that our current understanding of QFT is a first-order approximation,
which doesn't precisely apply on scales nearing the size of the
observable Universe.

Phil Hobbs
Guest

Wed Aug 17, 2016 10:50 pm   



Quote:
The only difference is that the virtual particles become real without
one being captured by the black hole.  They still don't explain why the
matter/energy has to come from the black hole.  Worse, no one has even
attempted to explain the "how" in any meaningful way other than to say
because of conservation of energy it *must* come from the black hole...
not very satisfying at all.  Why can't it come from my cat


Because of the math blizzard that you don't understand at all, and I understand only a bit better, despite two quantum field theory courses in grad school. "No one has ever attempted to explain" radar to a Hottentot either, I expect.

cheers

Phil Hobbs


Guest

Thu Aug 18, 2016 1:35 am   



On Thursday, August 18, 2016 at 9:21:35 AM UTC+10, rickman wrote:
Quote:
On 8/16/2016 7:02 PM, George Herold wrote:
On Tuesday, August 16, 2016 at 5:32:17 PM UTC-4, rickman wrote:
On 8/16/2016 5:17 PM, Dave Platt wrote:
In article <novtns$hg0$1_at_dont-email.me>, rickman <gnuarm_at_gmail.com> wrote:

Hawking radiation is caused by half of a virtual particle-antiparticle
pair falling into the event horizon and the other half escaping.

Think about that. Matter falls into a black hole which leaves the black
hole with less matter?

As I understand it (layman's explanation): each virtual
particle/antiparticle pair which appears, draws the energy of its
creation from the energy of the strongly-curved space-time in the
vicinity of the black hole. The same is true for any virtual-
particle-pair creation event... it "borrow" energy from the vacuum.

If the two virtual particles recombine, the energy is returned to
spacetime. This is what happens in the case of the vast majority of
such particle events, especially in flat or near-flat spacetime
regions.

If, on the other hand, one of the two virtual particles escapes (and
the other falls into the black hole), half of the "borrowed" energy
escapes. The total mass-energy in the region drops by that amount.

Don't ask me to try to lay out the math for this... I don't pretend to
understand the equations :-)

I'm not asking for math, I'm looking for an understanding. If something
can be extracted from the black hole by any mechanism, there would seem
to be a fundamental conflict with the idea that the black hole is
inexcapable.

I totally don't understand the idea of there being energy inherent in
the curvature of space-time.

I've also never understood the details of spontaneous generation of
particle pairs from the vacuum. Even if they recombine, they create a
pair of photons. What happens to the photons?

--

Rick C

Sit down and wathc the video I posted.
Smart guy talking about the "physics" of black
holes. You have to do the math!
To me it is a lot of fun.
(I watched it again...
some smart questions from the class too.)
The sun is a good analog for a black hole,
I missed that the first time.

He doesn't talk about the mechanism of exchange.
(I've said this before, but you have this
supieriority(sp) thing, which is kinda ugly.)
George H.

Sorry about the perceived attitude. I don't see it so I can't fix it.
It's strange coming out of the blue in your reply. I can only say if it
bugs you we shouldn't exchange.

I don't follow. Why do you *have* to do the math? Where in the math
will it explain matter/energy coming from the black hole? Applying math
to physics is based on principles that are deduced from observations.


Principles aren't deduced from observations. They are devised to conform to observations. Every now and then somebody devises a better set of principles which explain a bigger set of observations, or fit better to the observations we've accumulated. It's a process of induction rather than deduction.

Quote:
Understanding math without understanding the principles is not
understanding in my book.


The math embodies the principles. If you don't understand the math - at some level - you don't understand the principles. George Gamow's "Mr. Tompkins" books made some of the math accessible.

https://en.wikipedia.org/wiki/Mr_Tompkins

Quote:
I watched the video now and you are sort of right. He doesn't explain
the mechanics of how the matter/energy of the black hole decreases, but
he specifically addresses it when he says, the matter of the black hole
only consists of a surface and the matter/energy comes off that surface.
He seems to be saying that because the matter never *appears* to an
outside observer to fall into the black hole, it *can* escape without
violating any principles. When some discuss the singularity inside a
black hole, it would seem it is not obvious that there *is* a
singularity. If there is, how did it get inside the event horizon and
how could that matter ever get back across the event horizon?

Analyzing the process by thermodynamics is applying a well known
principle to a much less well known situation. We have no reason to
believe our laws are immutable for all time and space.


No. But it makes sense to devise laws that might be.

--
Bill Sloman, Sydney

rickman
Guest

Thu Aug 18, 2016 2:05 am   



On 8/16/2016 11:06 PM, bill.sloman_at_ieee.org wrote:
Quote:
On Wednesday, August 17, 2016 at 3:56:11 AM UTC+10, rickman wrote:
On 8/16/2016 1:42 PM, George Herold wrote:
On Tuesday, August 16, 2016 at 12:47:18 PM UTC-4, rickman wrote:
On 8/16/2016 12:30 PM, George Herold wrote:
On Tuesday, August 16, 2016 at 12:20:24 PM UTC-4, Tim Wescott wrote:
On Tue, 16 Aug 2016 01:23:34 -0400, bitrex wrote:

On 08/16/2016 01:04 AM, rickman wrote:
I was explaining black holes to a friend who asked about the LHC and
thought about what might happen if a tiny black hole were created.

I believe matter falling into a microscopic black hole would still
enter it in a similar manner to large black holes elsewhere in the
universe by orbiting the tiny black hole while being accelerated
causing energy to be emitted before crossing the event horizon.

A microscopic black hole, if such a thing could exist, would radiate
itself away via Hawking radiation before it had much of a chance to do
anything.


https://en.wikipedia.org/wiki/
Micro_black_hole#Stability_of_a_micro_black_hole

If such a thing as Hawking radiation exists.
IIRC Hawking radiation mostly follows from thermo-dynamics.
It's like black body radiation... Black holes have some temperature.
(Finding the temperature of a black hole is the hard part... :^)

I'm not sure that is a valid way to look at it. Everything that makes
up a black hole is on the other side of the event horizon. It may well
have a temperature, but we'll never feel any effect from it as nothing
can cross back through the event horizon. In a sense, the event horizon
of a black hole is an infinite heat sink at 0 °K. There may be
radiation from the space around the black hole, but nothing from the
black hole itself.

--

Rick C

Ahh, Rick I understand you are a smart guy. There are plenty of other smart guys
out there. I think the best (clearest) explanation I've seen/ read
(and it's been a while) was in a set of video lectures by Leonard Susskind.
Googling he's got a bunch... I don't recall which ones. Advanced stat. mech.
or maybe QM.

Black holes have a temperature. That's pretty cool. (NPI)
Here's wiki...(I only looked at the first few paragraphs.)
https://en.wikipedia.org/wiki/Hawking_radiation

Trouble is all of this is speculation and none is proven. I like a nice
mechanical explanation. Saying matter leaves a black hole by it
swallowing matter is not a very good argument. That's what Hawking
Radiation says.

That's not what Hawking radiation is about. As Dirac pointed out, the Heisenberg uncertainty principle means that virtual pairs of particles and anti-particles are always popping up everywhere and - mostly - vanishing again as they self-annihilate

http://www.universetoday.com/129471/what-are-virtual-particles/

If it happens at a back-hole event horizon, they can't self-annihilate.

A very pretty insight.


The only difference is that the virtual particles become real without
one being captured by the black hole. They still don't explain why the
matter/energy has to come from the black hole. Worse, no one has even
attempted to explain the "how" in any meaningful way other than to say
because of conservation of energy it *must* come from the black hole...
not very satisfying at all. Why can't it come from my cat?

--

Rick C

rickman
Guest

Thu Aug 18, 2016 2:18 am   



On 8/16/2016 7:51 PM, bitrex wrote:
Quote:
On 08/16/2016 05:34 PM, rickman wrote:
On 8/16/2016 5:19 PM, Phil Hobbs wrote:
On 08/16/2016 04:40 PM, rickman wrote:
On 8/16/2016 2:39 PM, Phil Hobbs wrote:
On 08/16/2016 12:47 PM, rickman wrote:
On 8/16/2016 12:30 PM, George Herold wrote:
On Tuesday, August 16, 2016 at 12:20:24 PM UTC-4, Tim Wescott wrote:
On Tue, 16 Aug 2016 01:23:34 -0400, bitrex wrote:

On 08/16/2016 01:04 AM, rickman wrote:
I was explaining black holes to a friend who asked about the LHC
and
thought about what might happen if a tiny black hole were
created.

I believe matter falling into a microscopic black hole would
still
enter it in a similar manner to large black holes elsewhere in
the
universe by orbiting the tiny black hole while being accelerated
causing energy to be emitted before crossing the event horizon.

A microscopic black hole, if such a thing could exist, would
radiate
itself away via Hawking radiation before it had much of a chance
to do
anything.


https://en.wikipedia.org/wiki/
Micro_black_hole#Stability_of_a_micro_black_hole

If such a thing as Hawking radiation exists.
IIRC Hawking radiation mostly follows from thermo-dynamics.
It's like black body radiation... Black holes have some temperature.
(Finding the temperature of a black hole is the hard part... :^)

I'm not sure that is a valid way to look at it. Everything that
makes
up a black hole is on the other side of the event horizon. It may
well
have a temperature, but we'll never feel any effect from it as
nothing
can cross back through the event horizon. In a sense, the event
horizon
of a black hole is an infinite heat sink at 0 °K. There may be
radiation from the space around the black hole, but nothing from the
black hole itself.

Hawking radiation is caused by half of a virtual particle-antiparticle
pair falling into the event horizon and the other half escaping.

Think about that. Matter falls into a black hole which leaves the
black
hole with less matter?


No, the hole loses mass turning the virtual particle into a real one.

So a "virtual" particle has negative mass? The black hole captures one
virtual particle and the other becomes real. What exactly is the
difference between a virtual particle and a real one?

A virtual particle is "borrowing" energy from the uncertainty principle,
and then paying it back fast enough that nobody notices. In the language
of quantum mechanics, energy and time are non-commuting observables, in
the same way that position and momentum are.

A virtual particle becomes real when another thing gives the original
system enough energy to pay back the loan, without relying on quantum
subterfuge.


So how does the black hole provide that energy? Curvature of space/time
is not energy that I am aware of.

--

Rick C

rickman
Guest

Thu Aug 18, 2016 2:59 am   



On 8/16/2016 8:00 PM, bitrex wrote:
Quote:
On 08/16/2016 02:39 PM, Tim Wescott wrote:
On Tue, 16 Aug 2016 12:50:57 -0400, bitrex wrote:

On 08/16/2016 12:20 PM, Tim Wescott wrote:
On Tue, 16 Aug 2016 01:23:34 -0400, bitrex wrote:

On 08/16/2016 01:04 AM, rickman wrote:
I was explaining black holes to a friend who asked about the LHC and
thought about what might happen if a tiny black hole were created.

I believe matter falling into a microscopic black hole would still
enter it in a similar manner to large black holes elsewhere in the
universe by orbiting the tiny black hole while being accelerated
causing energy to be emitted before crossing the event horizon.

A microscopic black hole, if such a thing could exist, would radiate
itself away via Hawking radiation before it had much of a chance to do
anything.


https://en.wikipedia.org/wiki/
Micro_black_hole#Stability_of_a_micro_black_hole

If such a thing as Hawking radiation exists.

It kind of has to, or else what we think we know about quantum field
theory must be pretty much wrong

The main question is not whether Hawking radiation exists, but what
happens to the information.

https://en.wikipedia.org/wiki/Black_hole_information_paradox

Well, true, and it probably does, but it hasn't been observed yet.

Quantum field theory doesn't predict either dark energy or dark matter,
yet astronomical measurements say they must exist. So quantum field
theory is kind of behind the 8-ball right now on explaining how the
universe works.


To my mind, a pretty interesting direction to head in would be to assume
that our current understanding of QFT is a first-order approximation,
which doesn't precisely apply on scales nearing the size of the
observable Universe.


I have considered similar ideas that our understanding of the universe
which is limited in explaining the large scale observations will be
expanded in the near future not unlike relativity expanded classical
physics after the Michelson–Morley experiment showed there was no
aether. There seems to be a lot of resistance to that idea. But
consider how "fabricated" much of the explanation is involving dark
matter and energy. I expect it will result in a very new theory of
life, the universe and everything in the next 20 or 30 years.

--

Rick C

George Herold
Guest

Thu Aug 18, 2016 3:31 am   



On Wednesday, August 17, 2016 at 7:21:35 PM UTC-4, rickman wrote:
Quote:
On 8/16/2016 7:02 PM, George Herold wrote:
On Tuesday, August 16, 2016 at 5:32:17 PM UTC-4, rickman wrote:
On 8/16/2016 5:17 PM, Dave Platt wrote:
In article <novtns$hg0$1_at_dont-email.me>, rickman <gnuarm_at_gmail.com> wrote:

Hawking radiation is caused by half of a virtual particle-antiparticle
pair falling into the event horizon and the other half escaping.

Think about that. Matter falls into a black hole which leaves the black
hole with less matter?

As I understand it (layman's explanation): each virtual
particle/antiparticle pair which appears, draws the energy of its
creation from the energy of the strongly-curved space-time in the
vicinity of the black hole. The same is true for any virtual-
particle-pair creation event... it "borrow" energy from the vacuum.

If the two virtual particles recombine, the energy is returned to
spacetime. This is what happens in the case of the vast majority of
such particle events, especially in flat or near-flat spacetime
regions.

If, on the other hand, one of the two virtual particles escapes (and
the other falls into the black hole), half of the "borrowed" energy
escapes. The total mass-energy in the region drops by that amount.

Don't ask me to try to lay out the math for this... I don't pretend to
understand the equations :-)

I'm not asking for math, I'm looking for an understanding. If something
can be extracted from the black hole by any mechanism, there would seem
to be a fundamental conflict with the idea that the black hole is
inexcapable.

I totally don't understand the idea of there being energy inherent in
the curvature of space-time.

I've also never understood the details of spontaneous generation of
particle pairs from the vacuum. Even if they recombine, they create a
pair of photons. What happens to the photons?

--

Rick C

Sit down and wathc the video I posted.
Smart guy talking about the "physics" of black
holes. You have to do the math!
To me it is a lot of fun.
(I watched it again...
some smart questions from the class too.)
The sun is a good analog for a black hole,
I missed that the first time.

He doesn't talk about the mechanism of exchange.
(I've said this before, but you have this
supieriority(sp) thing, which is kinda ugly.)
George H.

Sorry about the perceived attitude. I don't see it so I can't fix it.
It's strange coming out of the blue in your reply. I can only say if it
bugs you we shouldn't exchange.


Yeah me too... mostly I delete that stuff.
I figure if you want to understand something,
go study it, and then ask questions.
If you're only kinda interested...
Quote:

I don't follow. Why do you *have* to do the math? Where in the math
will it explain matter/energy coming from the black hole? Applying math
to physics is based on principles that are deduced from observations.
Understanding math without understanding the principles is not
understanding in my book.


I watched the video now and you are sort of right. He doesn't explain
the mechanics of how the matter/energy of the black hole decreases, but
he specifically addresses it when he says, the matter of the black hole
only consists of a surface and the matter/energy comes off that surface.
He seems to be saying that because the matter never *appears* to an
outside observer to fall into the black hole, it *can* escape without
violating any principles. When some discuss the singularity inside a
black hole, it would seem it is not obvious that there *is* a
singularity. If there is, how did it get inside the event horizon and
how could that matter ever get back across the event horizon?


Yeah I think that's my understanding, we only know about the surface,
from far away.
Quote:

Analyzing the process by thermodynamics is applying a well known
principle to a much less well known situation. We have no reason to
believe our laws are immutable for all time and space.

Hmm well there are lotsa non-equilibrium processes where
thermo (stat. mech.) doesn't apply. But in the end
I think it always has to work.... fundamental conservation laws.
Energy and Entropy.
That's why I said the mechanism is not all that important*
I figure an energy difference leads to a transfer of energy,
eventually. (I guess there are "frozen" glass states.)

George H.
*mechanism: how do virtual particles couple to the BH.
I have no f'ing idea, my guess is some gravitation thing.
unless the BH is charged or spinning or has an excess of
some other "thing".

Quote:

--

Rick C



Guest

Thu Aug 18, 2016 3:37 am   



On Thursday, August 18, 2016 at 10:22:13 AM UTC+10, rickman wrote:
Quote:
On 8/17/2016 7:35 PM, bill.sloman_at_ieee.org wrote:
On Thursday, August 18, 2016 at 9:21:35 AM UTC+10, rickman wrote:
On 8/16/2016 7:02 PM, George Herold wrote:
On Tuesday, August 16, 2016 at 5:32:17 PM UTC-4, rickman wrote:
On 8/16/2016 5:17 PM, Dave Platt wrote:
In article <novtns$hg0$1_at_dont-email.me>, rickman
gnuarm_at_gmail.com> wrote:

Hawking radiation is caused by half of a virtual
particle-antiparticle pair falling into the event horizon
and the other half escaping.

Think about that. Matter falls into a black hole which
leaves the black hole with less matter?

As I understand it (layman's explanation): each virtual
particle/antiparticle pair which appears, draws the energy of
its creation from the energy of the strongly-curved
space-time in the vicinity of the black hole. The same is
true for any virtual- particle-pair creation event... it
"borrow" energy from the vacuum.

If the two virtual particles recombine, the energy is
returned to spacetime. This is what happens in the case of
the vast majority of such particle events, especially in flat
or near-flat spacetime regions.

If, on the other hand, one of the two virtual particles
escapes (and the other falls into the black hole), half of
the "borrowed" energy escapes. The total mass-energy in the
region drops by that amount.

Don't ask me to try to lay out the math for this... I don't
pretend to understand the equations :-)

I'm not asking for math, I'm looking for an understanding. If
something can be extracted from the black hole by any
mechanism, there would seem to be a fundamental conflict with
the idea that the black hole is inexcapable.

I totally don't understand the idea of there being energy
inherent in the curvature of space-time.

I've also never understood the details of spontaneous
generation of particle pairs from the vacuum. Even if they
recombine, they create a pair of photons. What happens to the
photons?

--

Rick C

Sit down and wathc the video I posted. Smart guy talking about
the "physics" of black holes. You have to do the math! To me it
is a lot of fun. (I watched it again... some smart questions from
the class too.) The sun is a good analog for a black hole, I
missed that the first time.

He doesn't talk about the mechanism of exchange. (I've said this
before, but you have this supieriority(sp) thing, which is kinda
ugly.) George H.

Sorry about the perceived attitude. I don't see it so I can't fix
it. It's strange coming out of the blue in your reply. I can only
say if it bugs you we shouldn't exchange.

I don't follow. Why do you *have* to do the math? Where in the
math will it explain matter/energy coming from the black hole?
Applying math to physics is based on principles that are deduced
from observations.

Principles aren't deduced from observations. They are devised to
conform to observations. Every now and then somebody devises a better
set of principles which explain a bigger set of observations, or fit
better to the observations we've accumulated. It's a process of
induction rather than deduction.

Sorry, I used the wrong term. I meant to refer to inductive reasoning.
As you say principles are designed to suit data that is collected. The
math is fitted to the principle and used to make predictions. It is not
an explanation of the principle.


Understanding math without understanding the principles is not
understanding in my book.

The math embodies the principles. If you don't understand the math -
at some level - you don't understand the principles. George Gamow's
"Mr. Tompkins" books made some of the math accessible.

That is nonsense.


https://en.wikipedia.org/wiki/Mr_Tompkins

I watched the video now and you are sort of right. He doesn't
explain the mechanics of how the matter/energy of the black hole
decreases, but he specifically addresses it when he says, the
matter of the black hole only consists of a surface and the
matter/energy comes off that surface. He seems to be saying that
because the matter never *appears* to an outside observer to fall
into the black hole, it *can* escape without violating any
principles. When some discuss the singularity inside a black hole,
it would seem it is not obvious that there *is* a singularity. If
there is, how did it get inside the event horizon and how could
that matter ever get back across the event horizon?

Analyzing the process by thermodynamics is applying a well known
principle to a much less well known situation. We have no reason
to believe our laws are immutable for all time and space.

No. But it makes sense to devise laws that might be.

Laws have to fit the data, fitting the previously designed laws is
optional.


In general, previously designed laws do fit existing data pretty well. The unexplained component of the orbital precession of Mercury wasn't large

http://physics.ucr.edu/~wudka/Physics7/Notes_www/node98.html

--
Bill Sloman, Sydney

George Herold
Guest

Thu Aug 18, 2016 3:41 am   



On Wednesday, August 17, 2016 at 9:31:18 PM UTC-4, George Herold wrote:
Quote:
On Wednesday, August 17, 2016 at 7:21:35 PM UTC-4, rickman wrote:
On 8/16/2016 7:02 PM, George Herold wrote:
On Tuesday, August 16, 2016 at 5:32:17 PM UTC-4, rickman wrote:
On 8/16/2016 5:17 PM, Dave Platt wrote:
In article <novtns$hg0$1_at_dont-email.me>, rickman <gnuarm_at_gmail.com> wrote:

Hawking radiation is caused by half of a virtual particle-antiparticle
pair falling into the event horizon and the other half escaping.

Think about that. Matter falls into a black hole which leaves the black
hole with less matter?

As I understand it (layman's explanation): each virtual
particle/antiparticle pair which appears, draws the energy of its
creation from the energy of the strongly-curved space-time in the
vicinity of the black hole. The same is true for any virtual-
particle-pair creation event... it "borrow" energy from the vacuum.

If the two virtual particles recombine, the energy is returned to
spacetime. This is what happens in the case of the vast majority of
such particle events, especially in flat or near-flat spacetime
regions.

If, on the other hand, one of the two virtual particles escapes (and
the other falls into the black hole), half of the "borrowed" energy
escapes. The total mass-energy in the region drops by that amount.

Don't ask me to try to lay out the math for this... I don't pretend to
understand the equations :-)

I'm not asking for math, I'm looking for an understanding. If something
can be extracted from the black hole by any mechanism, there would seem
to be a fundamental conflict with the idea that the black hole is
inexcapable.

I totally don't understand the idea of there being energy inherent in
the curvature of space-time.

I've also never understood the details of spontaneous generation of
particle pairs from the vacuum. Even if they recombine, they create a
pair of photons. What happens to the photons?

--

Rick C

Sit down and wathc the video I posted.
Smart guy talking about the "physics" of black
holes. You have to do the math!
To me it is a lot of fun.
(I watched it again...
some smart questions from the class too.)
The sun is a good analog for a black hole,
I missed that the first time.

He doesn't talk about the mechanism of exchange.
(I've said this before, but you have this
supieriority(sp) thing, which is kinda ugly.)
George H.

Sorry about the perceived attitude. I don't see it so I can't fix it.
It's strange coming out of the blue in your reply. I can only say if it
bugs you we shouldn't exchange.

Yeah me too... mostly I delete that stuff.
I figure if you want to understand something,
go study it, and then ask questions.
If you're only kinda interested...

I don't follow. Why do you *have* to do the math? Where in the math
will it explain matter/energy coming from the black hole? Applying math
to physics is based on principles that are deduced from observations.
Understanding math without understanding the principles is not
understanding in my book.


I watched the video now and you are sort of right. He doesn't explain
the mechanics of how the matter/energy of the black hole decreases, but
he specifically addresses it when he says, the matter of the black hole
only consists of a surface and the matter/energy comes off that surface.
He seems to be saying that because the matter never *appears* to an
outside observer to fall into the black hole, it *can* escape without
violating any principles. When some discuss the singularity inside a
black hole, it would seem it is not obvious that there *is* a
singularity. If there is, how did it get inside the event horizon and
how could that matter ever get back across the event horizon?

Yeah I think that's my understanding, we only know about the surface,
from far away.

Analyzing the process by thermodynamics is applying a well known
principle to a much less well known situation. We have no reason to
believe our laws are immutable for all time and space.
Hmm well there are lotsa non-equilibrium processes where
thermo (stat. mech.) doesn't apply. But in the end
I think it always has to work.... fundamental conservation laws.
Energy and Entropy.
That's why I said the mechanism is not all that important*
I figure an energy difference leads to a transfer of energy,
eventually. (I guess there are "frozen" glass states.)

George H.
*mechanism: how do virtual particles couple to the BH.
I have no f'ing idea, my guess is some gravitation thing.
unless the BH is charged or spinning or has an excess of
some other "thing".


--

Rick C


Oh...
Did you get the part about where all the entropy of the universe is?
All the BH's are second,
I think he said cosmic background radiation is third,
and then comes the rest of us. :^)

George H.


Guest

Thu Aug 18, 2016 3:50 am   



On Thursday, August 18, 2016 at 9:44:47 AM UTC+10, rickman wrote:
Quote:
On 8/16/2016 10:50 PM, bill.sloman_at_ieee.org wrote:

The fact that LIGO has now picked up two black hole merger signals,
from medium-sized black holes (a few solar masses) does point up the
fact that black holes can merge, which might explain what might have
happened to any small black holes left over from the Big Bang.

I don't see that as much evidence. If *all* the small black holes were
swallowed up by larger black holes, why would any other matter have
escaped the same fate? Why wouldn't the entire universe be inside one
black hole?


Ask a theoretical physicist. Meanwhile, in the two black hole mergers that LIGO has detected, an appreciable proportion of the mass of two black holes was radiated away in the gravitational wave. Normal matter doesn't seem to be able to get rid of anything like as much energy as a gravitational wave..

Our galaxy currently seems to contain a few "hyper-velocity stars" which are moving fast enough to eventually escape our galaxy.

The current explanation is that they are halves of binary stars that got close to our galaxy's central black hole - the process that broke up the binary gave half the binary enough energy to completely escape the central black hole.

This isn't compatible with all the universe ending up in a single black hole (or at least not all that soon).

--
Bill Sloman, Sydney

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