ITN: Hawking Radiation 'Observed' !

[CraigS]

In the News (how could I have missed this one ! .. dated Sept 28):

Physicists may have observed Hawking radiation for the first time

In 1974, Stephen Hawking predicted that black holes emit thermal radiation due to quantum effects, which causes the black holes to lose mass and perhaps ultimately vanish. But despite numerous attempts to observe Hawking Radiation (HR), astronomers have so far detected no sign of it. Now, however, a team of scientists from Italy claims to have observed something that looks very much like Hawking radiation from an event hole horizon they created in the lab.

They created something called a "Refractive Index Perturbation" (RIP) in a dielectric substance, in which light can change the substance's refractive index. Interestingly, the RIP exhibited two event horizons (a black hole horizon and a white hole horizon). They also detected an unexpected photon emission which they've concluded was an indication of HR induced by the lab analogue of a black hole.

With these observations, the physicists have shown that it's possible to investigate the physics of black hole evaporation in other, more accessible systems. If future experiments confirm that this is Hawking radiation, the results could have implications on everything from the fate of black holes to how the universe may end.

I wonder whether they were wearing a 'Fez' hat during the observations ?


Cheers

[xelasnave]

But Carl recently said something I feel could be applied to attempts such as we have before us so as to build in the lab a mini model of what could be expected to exist at larger scales ....(and his words could be said to be out of context in that when dealing with black hole science we are dealing with real science...)


to invent mechanisms pulled from a lab experiment and then somehow scale them up, with no consideration as to the the scaling difficulties which are inherently present in such an effort.

I know this is stirring the pot but I look forward to the well considered replies my comment/observation may generate.

Yes it is cloudy here and I am bored

alex

[renormalised (Carl)]

Maybe one of the scientists was Tommy Cooper

[xelasnave]

Originally Posted by renormalised

Maybe one of the scientists was Tommy Cooper

Come on Carl have a strong coffee and pull your wonderful mind into gear and give me half a page of thought provoking comment raising points that will help all understand more about everything (and nothing).

Personally I dont like the concept that anything can escape our black hole I still think it offends the general premise of a black hole.

I think what is in operation is folk seeking to hang onto the coat tails of a great man and gain fame by proving him correct irrespective of the validity of the original premise....which is how black holes came into "reality" in the first place being a validation of GR in effect.
alex

[CraigS]

Originally Posted by xelasnave

Come on Carl have a strong coffee and pull your wonderful mind into gear and give me half a page of thought provoking comment raising points that will help all understand more about everything (and nothing).

Personally I dont like the concept that anything can escape our black hole I still think it offends the general premise of a black hole.

I think what is in operation is folk seeking to hang onto the coat tails of a great man and gain fame by proving him correct irrespective of the validity of the original premise....which is how black holes came into "reality" in the first place being a validation of GR in effect.
alex

Have you ever seen the Andrea Ghez videos of the observations of the centre of the Milky Way ? How do you explain the velocities and the movements of the stars there ?

Cheers

[renormalised (Carl)]

If future experiments confirm that this is Hawking radiation

That's the proviso....if it is what they say it is.

You are right, Alex, in saying what I wrote in a previous thread still applies, however where my words could be said to be out of context, I don't see where in this case. The scientists are dealing with real science, just as my comments were dealing with real science. Black holes are real science...they are quantifiable entities and whilst their direct, visual presence (like here's the hole....nice black spot in space) hasn't been totally forthcoming, their indirect presence most certainly has been verifiably observed.

There's nothing unusual about event horizons in physics...anywhere there is a boundary condition either setup by the experiment or inherent in the system that is being observed, there will be an event horizon. So, the only thing that has to be proved in this case is that the RIP in the dielectric is, in fact, an event horizon. It most likely is, however the joker in the pack here is whether it is behaving like a BH's event horizon and the physics involved is similar.

[renormalised (Carl)]

Well, Alex, Craig said one of them might be wearing a fez!!

[xelasnave]

“[W]e report experimental evidence of photon emission that on one hand bears the characteristics of Hawking radiation and on the other is distinguishable and thus separate from other known photon emission mechanisms,” the physicists wrote in their study. “We therefore interpret the observed photon emission as an indication of Hawking radiation induced by the analogue event horizon.”

The above sounds impressive but such a narrow interpretation will no doubt close the doors to any alternative interpretation one could reasonably conclude.

alex

[renormalised (Carl)]

Actually, Alex, something escaping a BH doesn't offend the general premise of a BH to begin with. It's a very common misconception of the public (and one, unfortunately, promulgated by scientists trying to be melodramatic about their science) that things cannot escape the pull of a BH. In truth, anything can escape the pull of a BH, so long as they have enough energy to keep from falling into and across the event horizon. Hawking Radiation forms from the creation of virtual particle pairs in the space above the event horizon of the BH. What happens is that one of the particles that is formed, loses energy and falls over the horizon, the other particle gains energy (transferred from the other particle) and escapes the BH. Over time this net loss of energy through the creation of virtual particle pairs robs the hole of energy (and therefore mass). The hole starts to shrink until it eventually gets to the stage where it's no bigger than a proton (and about as heavy as Mt Everest). Once it gets to that stage, the hole becomes unstable, the event horizon collapses and the hole explodes in a flash of gamma radiation...approximately equal to a 2 billion megaton (or so) nuclear device.

[CraigS]

I've been doing some research and reading on Scientific Modelling (following my post to Alex EU).

Here's a good paragraph to read, Alex (Push). Try it on !

Here's another one

Have fun !!


Cheers

[renormalised (Carl)]

It's not so much as narrow, Alex, as it is exclusive of other mechanisms because its effects are not seen to be either causative of, or a result of the usual photon emission mechanisms.

[xelasnave]

Originally Posted by CraigS

Have you ever seen the Andrea Ghez videos of the observations of the centre of the Milky Way ? How do you explain the velocities and the movements of the stars there ?

Cheers

Yes I certainly have...clear evidence in support of the push universe
I could explain such observations and fit them into a push universe and offer an alternative.. but lets face it you will probably suggest I am wrong and honestly Craig I could not manage the rejection I would take from such a rejection.


alex

[CraigS]

Originally Posted by xelasnave

Yes I certainly have...clear evidence in support of the push universe
I could explain such observations and fit them into a push universe and offer an alternative.. but lets face it you will probably suggest I am wrong and honestly Craig I could not manage the rejection I would take from such a rejection.


alex

If you can demonstrate (& convince the community) that the model fits the description from Wiki I forwarded you in my last post, then I would have no objections !! I'd be a believer !! (Not that this counts for much .. )



Cheers

[xelasnave]

Originally Posted by renormalised

Actually, Alex, something escaping a BH doesn't offend the general premise of a BH to begin with. It's a very common misconception of the public (and one, unfortunately, promulgated by scientists trying to be melodramatic about their science) that things cannot escape the pull of a BH. In truth, anything can escape the pull of a BH, so long as they have enough energy to keep from falling into and across the event horizon. Hawking Radiation forms from the creation of virtual particle pairs in the space above the event horizon of the BH. What happens is that one of the particles that is formed, loses energy and falls over the horizon, the other particle gains energy (transferred from the other particle) and escapes the BH. Over time this net loss of energy through the creation of virtual particle pairs robs the hole of energy (and therefore mass). The hole starts to shrink until it eventually gets to the stage where it's no bigger than a proton (and about as heavy as Mt Everest). Once it gets to that stage, the hole becomes unstable, the event horizon collapses and the hole explodes in a flash of gamma radiation...approximately equal to a 2 billion megaton (or so) nuclear device.

That is very interesting Carl and not offensive to common sense or to the science
However at the risk of appearing stupid yet again may I question the aspect of the explanation that suggests energy is "robbed" from the black hole by our virtual particle...do we not still have a point where the general premise is offended in so far as something still manages to leave that which can not be left? does this mean that energy can escape a black hole whereas mass cannot?
alex

[renormalised (Carl)]

Energy and mass are equivalent, remember. If the hole loses energy through the loss of a virtual particle, it also loses mass in the process.

[CraigS]

Originally Posted by xelasnave

That is very interesting Carl and not offensive to common sense or to the science
However at the risk of appearing stupid yet again may I question the aspect of the explanation that suggests energy is "robbed" from the black hole by our virtual particle...do we not still have a point where the general premise is offended in so far as something still manages to leave that which can not be left? does this mean that energy can escape a black hole whereas mass cannot?
alex

Isn't a black hole defined formally as a singularity and an Event Horizon ?

We should stop using the term "Black Hole" as there's more to one than this term suggests ..

Cheers

[xelasnave]

Originally Posted by CraigS

I've been doing some research and reading on Scientific Modelling (following my post to Alex EU).

Here's a good paragraph to read, Alex (Push). Try it on !

Here's another one

Have fun !!


Cheers

Thanks for the help Craig.
I would love to build a model of the push universe to test the stuff I run in my mind models via the neck top. The math would handle itself without interfering with testing various premises so any observation made of the behaviors observed in the model would already have the necessary supporting math.

I could then place a galaxy into a push environment and see if the outer stars would travel in accordance with the observations and thereby eliminate the current sad reliance upon dark matter to patch our present gravity models.

It would be great to see if my concept of a black hole is supportable and capable of generating the "jets" via an alternate approach.

alex

[xelasnave]

Originally Posted by renormalised

It's not so much as narrow, Alex, as it is exclusive of other mechanisms because its effects are not seen to be either causative of, or a result of the usual photon emission mechanisms.

Yes of course Carl.
The point I am really attempting to make is I see little need to draw in Hawking ..their experiment is exciting in its own right and I feel the attempt to throw Hawking radiation into the mix really takes away from their work.

alex

[CraigS]

Originally Posted by xelasnave

It would be great to see if my concept of a black hole is supportable and capable of generating the "jets" via an alternate approach.

alex

That it would !!

The 'Alex jet model' we'd call it !!

Love to see it in action !!


Cheers
PS: I'm enjoying this one !!

[renormalised (Carl)]

Actually, the only BH that has a formalised singularity is a non rotating BH that obeys the Schwarzchild Metric. Since BH's will be rotating (because they formed from a rotating object), the actual presence of a singularity can be called into question. If defined, the singularity will not be a point but a ring shaped object because the hole is rotating. So, the physics of the "singularity" are different and the maths describing are as well. A BH with these characteristics obeys the Kerr Metric (discovered by Roy Kerr back in the early 60's). These types of BH's are a little more complicated than your Schwarzchild hole.

In any case, if you have a complete law of quantum gravity, you can dispense with the singularity altogether because at a quantum level, the energy and mass of the hole become part of spacetime/superspace.