Evidence For Hawking Radiation?

Is there any direct physical evidence for Hawking radiation?

Has any physical object ever been observed to be emitting a unique form of radiation such that one would be confident in saying that the radiation is almost certainly Hawking radiation?

Or does Hawking radiation only exist on paper?

Robert L. Oldershaw
Fractal Cosmology/Discrete Scale Relativity

"Robert L. Oldershaw" wrote:

Is there any direct physical evidence for Hawking radiation?

Not that I know of.

Has any physical object ever been observed to be emitting a unique form
of radiation such that one would be confident in saying that the
radiation is almost certainly Hawking radiation?

Hawking radiation is black-body radiation, so you have to tell us what
kind of unique signature to expect.

Or does Hawking radiation only exist on paper?

If by that you mean "theoretically expected, but not yet observed", then
yes---like, at one time, neutrinos, the CMB etc. Science involves
testable predictions, so predicting something not yet observed (as
opposed to retrodicting something which has already been observed) is
part and parcel of science.

Note that the larger the black hole, the less Hawking radiation it
emits, so objects known to be (or suspected of being) black holes would
emit far too little to be detected (especially since much more intense
radiation from other sources would usually accompany such objects). On
the other hand, those that emit enough to be detected via Hawking
radiation would be difficult to identify.

Fractal Cosmology/Discrete Scale Relativity

What does DRS have to say about Hawking radiation? Any concrete,
testable, unique predictions?

On Sunday, September 1, 2013 6:06:10 PM UTC-4, wrote:
"Robert L. Oldershaw" wrote:

Is there any direct physical evidence for Hawking radiation?

Not that I know of.
------------------------------------------------------

My concern is that people discuss Hawking radiation as if its reality
is unquestioned - witness the tempest in a teacup over firewalls and
wormholes and the (also untestable) assumption of information
conservation in the black hole context.

I submit that not only has this putative radiation never been
observed, but that there are no unique properties of this putative
radiation by which it could be definitively tested, even IN PRINCIPLE.

[Mod. note: isolate a black hole in the lab, and it would be very easy
to make a definitive test. It's astrophysical contexts that we have
trouble with -- mjh]

DSR only concerns itself with the real physical world.

Here are 15 DEFINITIVE predictions and supporting PHYSICAL evidence:
http://www.academia.edu/2917630/Pred...ale_Relativity

Robert L. Oldershaw
http://www3.amherst.edu/~rloldershaw
Discrete Scale Relativity/Fractal Cosmology

[Mod. note: reformatted -- mjh]

On Monday, September 2, 2013 1:56:30 AM UTC-4, Robert L. Oldershaw wrote:
On Sunday, September 1, 2013 6:06:10 PM UTC-4, wrote:

[Mod. note: isolate a black hole in the lab, and it would be very easy
to make a definitive test. It's astrophysical contexts that we have
trouble with -- mjh]

-------------------------------------------------

"isolate a black hole in the lab"? Surely you jest.

[Mod. note: Correct -- mjh]

A definitive experiment is one that can be accomplished now or in the
foreseeable future. What you suggest is even more speculative than the
putative radiation.

[Mod. note: you said 'in principle'... -- mjh]

If Hawking radiation is total speculation, w1hy can we not admit it?
And why would we base serious and important physical reasoning on this
wind of hot air?

Robert L. Oldershaw

http://www3.amherst.edu/~rloldershaw

Discrete Scale Relativity/Fractal Cosmology

On 9/2/2013 12:56 AM, Robert L. Oldershaw wrote:
On Sunday, September 1, 2013 6:06:10 PM UTC-4, wrote:
"Robert L. Oldershaw" wrote:

Is there any direct physical evidence for Hawking radiation?

Not that I know of.
------------------------------------------------------

My concern is that people discuss Hawking radiation as if its reality
is unquestioned - witness the tempest in a teacup over firewalls and
wormholes and the (also untestable) assumption of information
conservation in the black hole context.

I submit that not only has this putative radiation never been
observed, but that there are no unique properties of this putative
radiation by which it could be definitively tested, even IN PRINCIPLE.

[Mod. note: isolate a black hole in the lab, and it would be very easy
to make a definitive test. It's astrophysical contexts that we have
trouble with -- mjh]


Test??? Tested???

observation would seem to be sufficient

and would there not be a characteristic curve in the intensity most
notably towards the end?

In article ,
David Staup wrote:
Test??? Tested???

observation would seem to be sufficient

In science we talk about 'testing' a model when we compare its
predictions to observations.

The prediction of Hawking radiation is testable in principle (which is
a requirement for any scientific theory) but not yet in practice.

and would there not be a characteristic curve in the intensity most
notably towards the end?

Yes, that's one prediction that could be tested. Indeed, any black
hole that could conceivably be produced in lab conditions would be
expected to evaporate via Hawking radiation on a very short timescale,
and so that would be the characteristic signal one would look for. (Of
course, if black holes don't evaporate, we'd be in trouble.)

--
Martin Hardcastle
School of Physics, Astronomy and Mathematics, University of Hertfordshire, UK
Please replace the xxx.xxx.xxx in the header with herts.ac.uk to mail me

On 9/3/2013 11:20 AM, Martin Hardcastle wrote:
Yes, that's one prediction that could be tested. Indeed, any black
hole that could conceivably be produced in lab conditions would be
expected to evaporate via Hawking radiation on a very short timescale,
and so that would be the characteristic signal one would look for. (Of
course, if black holes don't evaporate, we'd be in trouble.)

Yes, it is possible that if Hawking radiation isn't
there the difference would be quite noticeable. But
there could also be a lower limit where evaporation
stops (e.g. a Planck mass remnant, which would be
a WIMP, as some dark matter theories would have it:

http://en.wikipedia.org/wiki/Micro_b...he_final_state
) and this would make them safe to play with.

If I understand correctly you could in that case let
them acquire small amounts of mass which they would
quickly radiate off to get back to this lowest allowed
state. So there would be no danger that they become very
big, but also no danger that you lose them by total
evaporation. The best of both worlds!

--
Jos

[Mod. note: quoted text trimmed -- mjh]

On Tuesday, September 3, 2013 5:20:01 AM UTC-4, Martin Hardcastle wrote:
In article ,


The prediction of Hawking radiation is testable in principle (which is

a requirement for any scientific theory) but not yet in practice.

-------------------------------------------------------

The putative Hawking radiation plays an important role in the putative
black hole thermodynamics speculated upon by Bekenstein and Hawking
(also untestable in practice). The putative black hole thermodynamics
plays a central role in the imaginative "holographic principle"
speculations (also untestable in practice).

See how we build our card castles? If the starting assumptions are
wrong, the whole thing can collapse. If these assumptions cannot be
physically tested then we place science in an increasingly precarious
position as we add new layers to the castle.

One could predict that there are little green men dancing at the
centers of quasars. Does that mean the idea is testable in principle,
so that one would be justified in using the idea to guide the
development of fundamental physics in major ways for 45 YEARS?

I think that James Baggott's new book "Farewell To Reality" should be
required reading for anyone interested in science, and especially for
college-level students of science. It is, as they say, spot on.

Robert L. Oldershaw

On 9/3/2013 10:18 AM, Jos Bergervoet wrote:
If I understand correctly you could in that case let
them acquire small amounts of mass which they would
quickly radiate off to get back to this lowest allowed
state. So there would be no danger that they become very
big, but also no danger that you lose them by total
evaporation. The best of both worlds!

How intense would this "burst of radiation" be? If the above is correct
then we should expect "wandering" "plank mass remnants" to occasionally
encounter matter and pop off a burst of radiation. From how far away
might one detect this radiation?

also, this sounds like the ideal power source to me...

[mod. note: quoted text trimmed -- mjh]

In article ,
Robert L. Oldershaw wrote:
One could predict that there are little green men dancing at the
centers of quasars. Does that mean the idea is testable in principle,
so that one would be justified in using the idea to guide the
development of fundamental physics in major ways for 45 YEARS?

No. Firstly, clearly one isn't obliged to believe everything that's
testable in principle; one is just obliged to ignore everything that
isn't. Secondly, your analogy is flawed: the reason people believe
that there may be something like Hawking radiation is that it's very
hard to construct a quantum mechanical model of a black hole in which
something like Hawking radiation doesn't happen, and since quantum
mechanics is our most successful model of reality ever, there is some
motivation to take that seriously. (Note: 'something like Hawking
radiation'. It does not have to be exactly what Hawking predicted.)
This is not the case for your little green man model,

I think that James Baggott's new book "Farewell To Reality" should be
required reading for anyone interested in science, and especially for
college-level students of science. It is, as they say, spot on.

Well, if the amazon blurb is anything to go by, it mixes up things
that are not science at all (the anthropic principle), things that
could have been science but actually look like dead ends (string
theory) and perfectly respectable testable theories which are being
confronted by observations right now (SUSY). So I would guess the
author's aim is to throw a lot of mud and hope some of it sticks...

--
Martin Hardcastle
School of Physics, Astronomy and Mathematics, University of Hertfordshire, UK
Please replace the xxx.xxx.xxx in the header with herts.ac.uk to mail me