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Fraser
2007-Jul-02, 07:07 PM
The scientific consensus is that the Universe is expanding, having gotten its start in a single point 13.7 billion years ago. There are several lines of evidence to support this theory: ...

Read the full blog entry (http://www.universetoday.com/2007/07/02/before-the-big-bang/)

iantresman
2007-Jul-02, 10:03 PM
So a non-proven untestable theory is used to "model" a non-proven untestable theory, but it's all okay because they showed some maths?

It reminds me of Professor of Mathematics and Astronomy, Simon Newcomb (http://en.wikipedia.org/wiki/Simon_Newcomb) who no doubt did some maths, and declared, "Flight by machines heavier than air is unpractical and insignificant, if not utterly impossible."[Ref (http://www.nowalls.com/theme_info.cfm?theme_id=5)]. Two month later a couple of bicycle engineers, without any maths, did the impossible.

EDG
2007-Jul-02, 11:20 PM
So a non-proven untestable theory is used to "model" a non-proven untestable theory, but it's all okay because they showed some maths?

... says Mr Electric Universe. :whistle::liar:

Northwind
2007-Jul-03, 01:02 AM
Instead of being infinitely small and dense, it was compacted down into a ball of some volume and density.

So which is it? a mathematical singularity or a ball of "some" volume and density :confused:

Can't have it both ways!

As it stands does not stand in the way of the Electric universe :whistle:

EDG
2007-Jul-03, 01:18 AM
So which is it? a mathematical singularity or a ball of "some" volume and density :confused:

Can't have it both ways!

Well, if you actually read the article you'll see that this guy is suggesting it wasn't infinitely small and dense.

I know you love to misinterpret things and then make out that they're wrong as a result (of your incorrect interpretation), but nobody's saying it's "both at once".

RUF
2007-Jul-03, 02:13 AM
So a non-proven untestable theory is used to "model" a non-proven untestable theory, but it's all okay because they showed some maths?

And so "M-Theory" says as well....

cran
2007-Jul-03, 02:17 AM
So a non-proven untestable theory is used to "model" a non-proven untestable theory, but it's all okay because they showed some maths?I think your interpretation was wrong, but your analogy is not bad -

It reminds me of Professor of Mathematics and Astronomy, Simon Newcomb (http://en.wikipedia.org/wiki/Simon_Newcomb) who no doubt did some maths, and declared, "Flight by machines heavier than air is unpractical and insignificant, if not utterly impossible."[Ref (http://www.nowalls.com/theme_info.cfm?theme_id=5)]. Two month later a couple of bicycle engineers, without any maths, did the impossible. except that the declaration was that the maths does not exist which can extend beyond the Big Bang and make any sense,
until someone developed some maths to do just that ...
the issue wasn't about theories per se, but about the maths ...
so, that someone "showed some maths" is sort of central to the whole thing ...

Fraser, a couple of statements in your blog caught my eye:

According to Bojowald, a mathematical technique called Loop Quantum Gravity, which combines relativity and quantum mechanics, gives a different view of the early Universe.Isn't that the holy grail for those seeking a GUT or TOE?


The previous Universe was very similar to the space-time geometry we have in our current Universe.Doesn't this statement sit uncomfortably with The Bad Astronomer's?:

No doubt the physical aspects of this previous Universe were somewhat different; the quantum uncertainties at the moment of bounce would ensure that. It may have been much like ours, or it may have been quite alien. In his equations, itís the volume of that previous Universe that cannot be determined.http://www.badastronomy.com/bablog/2007/07/01/what-happened-before-the-big-bang/

... and also with the report from Space.com?

One implication of this "cosmic forgetfulness," as Bojowald calls it, is that history does not repeat itself-the fundamental properties of the current era of the universe are different from the last, Bojowald explained. "It's as if the universe forgot some of its properties and acquired new properties independent of what it had before," he told SPACE.com.http://www.space.com/scienceastronomy/070702_mm_big_bang.html

Exposed
2007-Jul-03, 02:43 AM
So which is it? a mathematical singularity or a ball of "some" volume and density :confused:

Can't have it both ways!

As it stands does not stand in the way of the Electric universe :whistle:

A mathematical singularity doesn't necessarily mean there MUST be a physical singularity as well, it's just the point where mathematics break down. If new mathematics and physics develop that take over where "old" mathematics break down, then that's progress.

Remember, there was a time.....

....when Romans uses Letters to represent numbers (the roman method of numbering was unnecessarily complicated and limited complex operations)

....when the concept of 0 as a number was nonexistant

....when calculus did not exist

I'm quite fascinated as to how our mathematics will evolve over the next hundreds and thousands of years, making the most hard to grasp concepts today that current math have a tough time dealing with seem just trivial in a more developed mathematical abstract.

John Mendenhall
2007-Jul-03, 12:38 PM
Maybe.

Tim Thompson
2007-Jul-03, 10:05 PM
The idea of an "oscillating universe" is certainly not new, and has been around almost as long as Big bang cosmology has been around. But recent advances in theoretical studies of quantum gravity & string theory have put the idea in a new context. Bojowald has already done a fair amount of work along those lines (i.e., a list of 80 papers (http://adsabs.harvard.edu/cgi-bin/nph-abs_connect?db_key=AST&db_key=PHY&db_key=PRE&qform=AST&arxiv_sel=astro-ph&arxiv_sel=cond-mat&arxiv_sel=cs&arxiv_sel=gr-qc&arxiv_sel=hep-ex&arxiv_sel=hep-lat&arxiv_sel=hep-ph&arxiv_sel=hep-th&arxiv_sel=math&arxiv_sel=math-ph&arxiv_sel=nlin&arxiv_sel=nucl-ex&arxiv_sel=nucl-th&arxiv_sel=physics&arxiv_sel=quant-ph&arxiv_sel=q-bio&sim_query=YES&ned_query=YES&aut_logic=OR&obj_logic=OR&author=Bojowald%2C+Martin&object=&start_mon=&start_year=&end_mon=&end_year=&ttl_logic=OR&title=&txt_logic=OR&text=&nr_to_return=100&start_nr=1&jou_pick=ALL&ref_stems=&data_and=ALL&group_and=ALL&start_entry_day=&start_entry_mon=&start_entry_year=&end_entry_day=&end_entry_mon=&end_entry_year=&min_score=&sort=SCORE&data_type=SHORT&aut_syn=YES&ttl_syn=YES&txt_syn=YES&aut_wt=1.0&obj_wt=1.0&ttl_wt=0.3&txt_wt=3.0&aut_wgt=YES&obj_wgt=YES&ttl_wgt=YES&txt_wgt=YES&ttl_sco=YES&txt_sco=YES&version=1) authored or co-authored by Bojowald from the NASA ADS database). Also keep in mind Paul Steinhardt (http://www.physics.princeton.edu/~steinh/)'s colliding branes model from string theory, which has been around for several years now. Or sample Gasparini & Veneziano, 2003 (http://adsabs.harvard.edu/abs/2003PhR...373....1G), a 212 page magnum opus on pre big bang cosmology, which appeared in Physics Reports.

The particular paper referenced here presents one model inspired by loop quantum gravity (i.e., Rovelli, 1998 (http://relativity.livingreviews.org/Articles/lrr-1998-1/index.html), Bojowald, 2005 (http://relativity.livingreviews.org/Articles/lrr-2005-11/index.html)). Here is the first paragraph of the paper, which serves as the abstract for Nature (I have removed footnote superscripts):


First Paragraph (Bojowald)
Was the Universe before the Big Bang of classical nature, described well by a smooth spaceĖtime? Or was it in a highly fluctuating quantum state? This is one of the most basic questions that we may ask once it is accepted that there was something before the Big Bang. Loop quantum gravity applied to isotropic models has shown that the quantum evolution of a wavefunction extends through the Big Bang. Although a general demonstration is still lacking, this may suggest that calculations, and possibly future indirect observations, may allow us to see the Universe as it was before the Big Bang. Here, we analyse an explicit model with a pre-Big Bang era, indicating limitations that would imply that it is practically impossible to answer some of our questions. Assumptions (or prejudice) will remain necessary for knowing the precise state of the Universe, which cannot be fully justified within science itself.

It looks to me like the "cosmological forgetfulness" mentioned above is an application of Heisenberg's uncertainty principle to the "bounce" of an oscillating universe. Bojowald doesn't call it that, and my description may be inaccurate, but it looks close.

Tim Thompson
2007-Jul-03, 10:15 PM
So a non-proven untestable theory ...
In reference to big bang cosmology, this is unacceptable. You could not be more wrong if you tried. The idea that big bang cosmology is "untestable" is ludicrous. Not only is it easily & readily testable, it has been tested. It has yet to fail any test, in any way, shape manner or form, of sufficient weight to call the theory into question. You are challenged to show how it is that the theory is untestable. You are challenged to show any test that big bang cosmology has failed, of sufficient weight to call the theory seriously into question.

Of course, this Story Comments part of the board may not be the proper place to carry on such a conversation. But you may consider your bluff called.

RussT
2007-Jul-04, 07:12 AM
How are the Big Bang "Initial Conditions" any more 'testable' than any other "Intitial Conditions" that could be hypothesized, accept of course for Forever or any infinite in time models?

RussT
2007-Jul-04, 07:42 AM
Sean Carroll
Says:

July 1st, 2007 at 2:11 pm
I wrote something about this here:

http://cosmicvariance.com/2007/04/27/how-did-the-universe-start/



The real problem with all such models is that, from the point of view of the other side of the bounce, the entropy is decreasing as the universe collapses, which seems crazily finely-tuned. Either that, or the entropy is at a minimum at the bounce, for no especially good reason.

Singularities are going to have to be resolved somehow, but reality is likely to be quite a bit more complicated than simple bounce models.

Sean has a very honest approach to all of this a makes some very good points!

I do not seem to be able to 'copy' any of this. But his second and third paragraghs are very honest.

He undeniably says...Some form of singular solution needs to be found BUT...Houston, there's a Problem!

It is just absolutely incredible to me, that SO MANY think that the ONLY solution possible MUST fit a FLRW profile, or that since Einstein didn't know a thing about SMBH's, "Exotic Matter", or Voids, that everyone is SO locked into their 'beliefs' of the "Beginning"!

imported_gemini
2007-Jul-04, 04:12 PM
This is the ancient oscillating universe hypothesis. Big deal, the usual theoretical mathematical gymnastics, no new evidence whatsoever, supposedly testable but not. What's with "Phil's" shots at creationists? Why debate with pseudo-science? How old is "Phil" and why is he insecure? Can we stick with observation rather than vapid speculation?

wstrnmdw
2007-Jul-04, 04:25 PM
The illustration accompanying Fraser's article shows the universe in "phase space". What is that?

jamini
2007-Jul-04, 05:58 PM
Phase space is a physics term for all possible states of a system, in this case space.

I find the whole concept fascinating, if not all that dissimilar from String/M-theories. Although strictly mathematical and philosophical at this point, the detection of Gravitons or other predicted massless particles by the new LCH at CERN could bring these theories right into the forefront of modern physics. Now that would be a paradigm shift!

Twinsun
2007-Jul-04, 06:14 PM
for the religious people : before the Creation of our Universe, there was NOTHING and u may already know that ;)

for the scientists : before the BIG BADA-BOOM, teh Universe as we know it today was certainly NOT there... there could have been the nothingness our some unkown antimatter ( like the black holes ) OR there could have been some other universe or some other dimensional representation ... anyway did u ever think that before the BIG BANG ( which produced the 3D space ), maybe there was just the 2D environment ??? try and think about the BIG BANG like some sort of level-up, like an upgrade if you so desire :)