Echos from *before* the Big-Bang

[ngcles]

Hi All,

Interesting article on the ABC website by Stuart Gary (of Starstuff).

http://www.abc.net.au/news/stories/2010/11/29/3079213.htm?section=justin


Best,

Les D

[CraigS]

Thanks Les;

This seems like another good follow-up article to Rolf's post (http://www.iceinspace.com.au/forum/showthread.php?t=68543) the other day.

Cheers

[multiweb]

Did I hear a big badaboom? :question:

[Robh]

Les, fascinating stuff.

Some more edible reading here ...
http://physicsworld.com/cws/article/news/44388

So much for the claimed random uniformity of the CMBR. Now we have the possibility of concentric circles. Is this the end of inflation theory?
I can buy that eventually black holes will eat up all the matter in the Universe. But can someone explain how black holes evaporate.

Regards, Rob

[CraigS]

Hawking Radiation.

Cheers

[Robh]

Craig, thanks for that. Most succinct reply ever!
I didn't realise that Hawking radiation could lead to total evaporation of the black hole.

Regards, Rob

[CraigS]

No worries, Rob.

Even more interesting is the Black hole information paradox (http://en.wikipedia.org/wiki/Susskind-Hawking_battle#Black_hole_war).

This issue has been going on for a long while. The solutions to the paradox (http://en.wikipedia.org/wiki/Susskind-Hawking_battle#Main_approaches_to_t he_solution_of_the_paradox) is very interesting. It shows just how debatable the whole subject really is.

Cheers

[Robh]

To begin, let me say I'm no expert on Big Bang cosmology.

From what I've read about black holes their temperature increases exponentially as they radiate away mass. The black holes then likely dissolve in situ in a burst of gamma rays. If the Universe is expanding, by what mechanism are these black holes going to collide to form the ripple of another Big Bang?
It seems to me a bit of a jump to say that the circles in the CMBR allow us to see through the Big Bang. Is it likely that an earlier signature will still be observable following another Big Bang? How will the ages of the concentric signatures match the age of distant objects embedded in the CMBR?
Is it possible for the concentric circles to indicate a Big Bang that occurred in stages with multiple inflation events?

Regards, Rob

[CraigS]

Rob;

I'm going to think of this one fairly lightly. It reminds me a bit of tea-leaf reading of patterns in the bottom of a teacup. (Or is that crop-circles?). I get the same feeling when I read about the 'holes' in the CMBR, which they say may represent where matter condensed to form galaxy structures. (And yes … this is an opinion ;) ).

They have speculated about the possibility of multiple Bangs. The real news for me, is that they found a six-sigma level of significance that a concentric circle pattern exists in WMAP (7 year) and BOOMERanG98 data, thus eliminating the possibility of an instrumental cause for the effects.

I guess they wouldn't have found that, if they hadn't speculated in the first place.

So the door is now open for the story-tellers to come up with stories as to how these patterns may have gotten there. (Did I hear some say Erik Von Daniken ?)



Theory allows for this to happen today .. black holes collide to form super massive black holes .. galaxies collide, etc.
The metric expansion of space however, is observed on a different scale. Where galaxies are moving apart with the expansion of space, fair enough .. I get ya .. its not likely that these (& their enclosed SMBHs) would collide.
I don't see this as a problem for their story, however.



Most of this is explained in the first three pages of the Penrose et al paper (http://arxiv.org/pdf/1011.3706v1). This is the speculative part of what they're reporting and it seems like a fairly thin analysis to me (another opinion !! ;) )

Cheers

[sjastro]

Hawking radiation as a blackbody radiation is the only radiation emitted by a black hole.

Other forms of radiation such as X-rays are not emitted by black holes, but rather by the heating of matter to extremely high temperatures before it passes through the event thorizon.

Regards

Steven

[CraigS]

Ahhh .. there's a magic term .. 'blackbody'.

Interestingly, I've read that the Sun is a 'blackbody' … it radiates light, but it reflects none. As I understand it, this formally defines it to be a 'blackbody' !!

Also, black holes have a temperature. Presumably, they thus also radiate heat.

Is it the Hawking Radiation only which carries this heat ? (Separate from the accreting matter, that is)

Cheers

[sjastro]

A blackbody is defined as being able to absorb light of all frequencies and emit heat.
I don't think the Sun would qualify as a blackbody under this criteria.:)

A BH can only generate heat through Hawking radiation.
The heat output is sensational. For a solar mass BH you will raise the temperature by one ten millionth of a degree above absolute zero. For larger BHs the increase in temperature is even less as a smaller percentage of mass is converted to Hawking radiation.

The temperature from matter falling into a BH is a very different picture. The temperature can be raised by hundreds of millions of degress.

Regards

Steven

[CraigS]

So the temperature is inversely proportional to the mass, eh ? (Apart from the temperature of the falling matter, that is .. they must consider this to be a separate item of the overall temperature of the whole thing (??))

Really interesting (to me), is that as a BH emits Hawking Radiation, the mass drops, and hence the temperature increases and, as it approaches Planck mass, the temperature is about the same as the Big Bang 10∧32 degrees !! (I think we've spoken of this in the past).

Clearly, they've been thinking about the relationships between the origin of the BB, and the possible role BHs may have played in it, for a while.

Penrose seems to see BHs playing major roles in multiple ways, though.

Interesting.

Cheers

[Robh]

I was reading this article form 6 years ago ...
http://imagine.gsfc.nasa.gov/docs/features/news/14may04.html

Of particular note are the last two paragraphs.

Also, more recently ...
http://www.technologyreview.com/blog/arxiv/24956/

Frampton talks of two inflationary periods.

Regards, Rob

[CraigS]

Hmm … I would think this to be a leading contender for the Hot Dark Matter (HDM) candidate. The smaller the hole gets, (due to evaporation), the hotter it gets, hence I think this would be considered an HDM theory.
The HDM idea is still in contention, I think although Cold Dark Matter seems to still be favoured.
CDM has problems still though … the cuspy halo and missing satellites problems (http://en.wikipedia.org/wiki/Cold_dark_matter) … swings of the pendulum it seems !



Hmm interesting again.
Thats a pretty big range !! …


also ..


There's been quite a lot of development in the microlensing research field, this year I believe. We should keep an eye out for more words on this in the future.

Interesting stuff !

Perhaps we just live inside a black hole .. that make us all holograms, eh ?
:lol::)

Cheers

[CraigS]

Just released yesterday …

About a month after the initial paper, three groups rebut the Gurzadyan/Penrose cyclic universe theory:

No evidence of time before Big Bang (http://www.nature.com/news/2010/101210/full/news.2010.665.html), published 10th Dec 2010.



Interesting to see another model from a distinguished scientist (Penrose), going up against the mainstream one.

Just goes to show that the Scientific process does allow for consideration of competing theories.

Cheers

[mjc]

Or maybe the power of the internet is challenging old ways of doing things. ArXiv doesn't present the same hurdles as the traditional paper journals and thus scientists have greater liberty of what they publish.

I think the rationale was intended as a quicker way of getting ideas circulated (as preprints) before going to conventional journals but appears to have evolved into an effective mechanism to publish without the intention of attempting to get past the restrictions of the traditional journals.

Old model slow - difficult to introduce new ideas - bias can exist on what gets published.

New model quick - not a lot to prevent new ideas - no bias in what gets published - but that means that quality of what gets published can be lacking.

My 2c of speculative opinion.

Mark C.

[CraigS]

Yep. I agree.
And it would seem the end result may be the same independent of the path chosen .. ie: accepted or rejected by the scientific community. Via the new model, the debate is more public which means we get more insight into the pros and cons (which I see as beneficial, as its another way to learn rapidly about the topic),

I also think that the length of time for them to publish in books is reduced nowadays, and also has the benefits of:

- giving them reputations and;
- lining their pockets.

If they are as famous as Penrose (because he's published books), AND then they pre-print publish on arXiv, it fast-tracks things even more.

I think its great ! It requires amateurs (like us) to develop different skills though .. as you say .. to weed out the 'wheat from the chaff'.

Interesting.

Cheers