SBS Docco on Hawking & Big bang

[Dobman]

i see there's a documentary on tonight ( Sun 27/4) @ 8.30pm on SBS.
It's called "The Hawking Paradox". The tv guide says:
" Challenges physicist Stephen hawking's famous mathematical proof of the Big Bang theory"
Might be worth a look
Simon

[OneOfOne]

Yep, and from what I see in the guide it is the only thing on TV worth a look!

[maksutover]

Ive got this. Very interesting and the final twist in his theory is certainly subject to debate.

[Alchemy]

I dont know how many people would understand the math..... certainly not me , but id like to have a look anyway.

[jjjnettie]

:( We can't get SBS.
I really do miss it.

[drmorbius]

Don't fret Jeanette... a Google search will find the show (albeit in pieces) on YouTube.

[Ian Robinson]

Not to mention :

SBS :

8:30pm The Hawking Paradox.

Tonight on Aunti :

12:30am Day of the Triffids
2:00am Invaders from Mars

and on Nine :

11:45pm Red Planet

What to watch and what to tape on VCR ?

And the kids go back to school tomorrow :party2::cheers:

[dugnsuz]

so no-one will be watching "so you think you can dance" then!!??:P:P:P

[Ian Robinson]

No one with more than one functioning braincell anyway ....

The TV here rarely goes to the commercial stations on Sunday nights , nothing worth watching there.

Lets see what stimulating stuff the commercials have to offer tonight :

Seven :
8:30 Greys Anatomy
9:30 Brothers and Sisters
10:30 Cheaters
11;30 It’s Always Sunny in Philedlphia

... a dead lost tonight ...

Nine
8:30 CSI
9:30 Without a Trace
10:30 CSI (Aus)
11:45 Movie : Red Planet …. Finally something worth watching , hopeless until then.

Ten
8:50 So You Think You Can Dance
9:40 Rove
10:50 Formula One Grand Prix
1:30am IPL 20-20 Cricket
..... are they trying ?
.....

See what I mean ....

[Meadehead]

Thanks for the heads up Simon. I skimmed through the tv guide but must have missed it, I enjoyed watching it!

[renormalised]

Just watched "The Hawking Paradox" and then realised that I'd seen it before on SBS about a year or so ago (or it might have been the ABC).

Good show though.

Got me thinking.....information can't be lost when it enters a black hole, otherwise Hawking Radiation wouldn't exist. Here's why....3rd Law of Thermodynamics.....entropy. Any system will always tend towards a maximum state of entropy, disorder, over time. Now, black holes themselves you might think are a state of maximum entropy. They're not. I'd contend that given their characteristics they're actually probably as close to an ideally ordered state as you can get. Infinite gravitational pull, infinite density, zero size. A highly disordered state would, by necessity, be none of these because to be disordered implies having no characteristics to speak of at all. So, the production of virtual particle pairs at the event horizon of a black hole, where one escapes and one falls in, is in fact not a loss of information but a gain, as one of the particles manages to escape the clutches of the hole. Eventually what goes in comes out, but not in the way you might think :-). The hole then keeps evolving in this way till it reaches a point where it can no longer sustain its event horizon, so it breaks down and quantum fields come into play....the hole explodes in a burst of high energy gamma rays and disappears. This is where the talk of multiverses and such comes into play. It's all to do with entropy and the preservation of information, but in what I believe is a direct violation of the 3rd Law as we know it, because ordinarily entropy destroys information. However I feel that the wacky nature of reality that dominates Quantum Theory preserves the information in uncertainty.... that the randomness of the quantum is also underlain by an atypical and quirky type of order. This is where the "information" that a black hole swallows eventually goes to.

Now, the only thing is to try and prove it!!!!. I only wish my maths was good enough:(

[edwardsdj]

This is actually the second law of thermodynamics. The third law relates to the entropy of a system approaching zero as the temperature approaches absolute zero.

I've always seen a black hole as an entropy pump. I believe this is what Hawking was originally trying to say. Information goes in (stars, planets, possibly lifeforms) and blackbody radiation comes out (Hawking radiation).

So while the black hole itself is in a very low entropy state (as you suggest) the effect of the hole is to convert information (low entropy state) into blackbody radiation (highest possible entropy state). Consequently all information is destroyed. This is completely consistent with the second law of thermodynamcis.

Interesting documentary :)

[renormalised]

Thanks for correcting me on that....I was trying to remember which law it was. I had a feeling it was the 2nd law:)

One point.....you could even say that the blackbody radiation itself is a form of information and not necessarily the highest state of entropy you can have. Whilst it's for all intents and purpose about as disordered as you would normally get, a completely disordered state would by rights follow on in the 3rd Law of Thermodynamics (as you've previously mentioned), at a temp of absolute zero. But even then, we have no idea whether you can ever actually reach absolute zero, as you have the background quantum fluctuation of spacetime in which the particle rests. If at absolute zero, the order of a particle becomes zero or undefined, then you might as well say that quantum fluctuations in the spacetime field prevent total disorder. In actual fact, a definition of zero is a value and therefore can't be total disorder which implies nothing of any value (complete and utter non-existence). It would be better to say it was undefined, which also implies some hint of order to the system, no matter how vague or small it might be.

[edwardsdj]

The third law of thermodynamics in effect states that it is impossible to reach absolute zero temperature.

Another way of stating the third law is that the entropy of a system approaches zero as the temperature approaches absolute zero:

http://en.wikipedia.org/wiki/3rd_law_of_Thermodynamics

Absolute zero is the minimum possible entropy state. Pure thermal radiation (blackbody radiation) the maximum.

Hope this helps clear some things up :)

Have fun,
Doug

[skwinty]

A question here on this statement.
Given the extreme pressure and temperature experienced by the mass in this circumstance, I would have thought that the atoms and their associated particles would be completely disassociated into some kind of particle soup.
Where would you find order in that? Is enthalpy the correct term here?

[renormalised]

That's in terms of radiation...energy. However, compared to a lump of coal, pure blackbody radiation is highly disordered. It really depends on how you define entropy, order/disorder w.r.t. whatever you're looking at.

Semantics, yeah I know, but what you said is correct.

[renormalised]

They are, and you're correct in stating that. However, the order comes in the values of the system as a whole. It has a defined mass, the gravitational pull is of a certain intensity (even if it does approach infinity), it has a specific density, size etc etc. If it was in a highly disordered state, it would have none of those.

Just had a thought.....given that at absolute zero, entropy reaches its minimum state and everything is in total disorder, by rights a black hole would cease to exist. It would instantly radiate away all the energy it had (gravitational, angular momentum etc etc) because its surroundings would be devoid of everything...light, heat etc etc. Since it would have to obey the 1st law (i.e. "hot" flows to "cold"), it would lose its order completely by radiating it away. However, it would only be a momentary thing....the moment it's surroundings reached maximum disorder, the hole would flash vapourise into nothingness and instantly raise its surrounding to a temp' of trillions of degrees. So, it'd be going from the sublime to the ridiculous, so to speak.

But all that is assuming the hole doesn't lose order as the temp decreases. It would, however you have the problem of the singularity and the damn cold. One is (for sake of argument) an infinitely deep gravitational well. The other is just a precisely defined temp at which everything grinds to a halt. If the gravitational well is infinitely deep, then it must possess infinite energy. It wouldn't matter how cold it got, how do you "freeze" infinite energy??!!!! It would be infinitely hot right at the zero point of the singularity.

Figure that one out.

[edwardsdj]

Entropy is a precise physical parameter with a very definate physical meaning (like mass or temperature).

One way of looking at entropy is the number of parameters you need to describe a system. If the number of parameters is high, entropy is low. Conversely, if the number of parameters is low, entropy is high.

At absolute zero, all atoms have ceased all thermal motion so the only way to completely describe the system is by stating the exact position of each and every particle in the system. Entropy is low (zero according to 3rd law).

Pure thermal radiation (blackbody radiation) is described by a single parameter, the temperature. Entropy is high (highest possible).

A non-rotating, uncharged black hole is described by a single parameter: it's Swartzchild radius. Entropy is high (highest possible).

If you think of a whole egg, it has a shell, yoke, white, etc... the number of parameters needed to describe this state is higher than the number of parameters needed to describe a scrambled egg which exhibits none of this structure. The entropy of the unscrambled egg is lower than that of the scrambled egg.

[skwinty]

If you look at the experiment where you take a box of a given size, partitioned in the middle with two different gases, one in each compartment.
Pressure and temperature constant. As long as the two gases are kept separate the system is ordered.
however when you open the gate and the gases mix the system is disordered.The mass hasn't changed and neither has the pressure or temperature.