Before the Univers started it's exspanding everything was supposedly condensed into 1 area did absolute zero exist, was there no energy?
Answers and Replies
#2
CrystalStudios
Mmmm, Frankly - even being someone who recognizes the power of science. I think most would agree that the events that occured roughly 1/4 of a second after the BB or less are impossible to determin. After 1/4 things developed into what we think of them as, our materials etc...
...but before 1.4 it is very much flimsy. There are theories but even I would not consider them strong enough to last.
For instance, before the BB there may have been nothing at an point. This universe was not even here.
Originally posted by Eh Waiting for a quantum theory of spacetime to answer what was there at t=0.
Loop quantum cosmology as developed by Bojowald is such
a theory and extends continuously back to zero and before.
Bojowald is just a postdoc working for Ashtekar at Penn State.
So the most impressive statements about this are coming from Ashtekar, giving overviews based on work by Bojowald in collaboration with other people. the results are recent and, while not conclusive, very suggestive that there probably was no singularity at time zero.
Bojowald "Absence of Singularity in Loop Quantum Cosmology" arxiv:gr-qc/0102069 (this is just 4 pages)
Bojowald/Morales-Tecotl "Cosmological applications of loop quantum gravity" arxiv:gr-qc/0306008 (this a recent 2003 paper with references to online papers by Bojowald and co-authors, however this one is 42 pages)
Bojowald "Homogeneous Loop Quantum Cosmology" arxiv:gr-qc/0303073 (this has computer-generated pictures on page 16 of a wave packet moving right through the classical time-zero singularity, however the paper is over 20 pages and quite technical)
for a non-technical overview:
Ashtekar "Quantum Geometry in Action: Big Bang and Black Holes"
arxiv:math-ph/0202008
these are all on line, to turn the arxiv code into a link type, for example,
http://www.arxiv.org/math-ph/0202008 [Broken]
that gives the abstract, with a button to download the PDF
Current work in the quantum theory of spacetime is exploratory and suggestive rather than conclusive. LQG only succeeds as a model of space and the 4D version of it----Spin Foams----was only recently invented. So what you say: "waiting for a quantum spacetime model" is exactly right. I would like to see a spinfoam model calculated for timezero. But in the meantime Bojowalds ad hoc treatment is shedding some light on the subject.
Originally posted by The Grimmus Before the Univers started it's exspanding everything was supposedly condensed into 1 area did absolute zero exist, was there no energy?
i agree with crystal studios that it is impossible to discover what happened in the very beggining, but as for your question of energy i would say that yes,it would be abolute zero temp.. because heat is the movement of particles and in the early beginging there were no particles. there might have been energy in the e=mc2 sence, but as for thermal energy, probobly not.
#6
Ace-of-Spades
Originally posted by CrystalStudios Mmmm, Frankly - even being someone who recognizes the power of science. I think most would agree that the events that occured roughly 1/4 of a second after the BB or less are impossible to determin. After 1/4 things developed into what we think of them as, our materials etc...
...but before 1.4 it is very much flimsy. There are theories but even I would not consider them strong enough to last.
For instance, before the BB there may have been nothing at an point. This universe was not even here.
Its not quite as large as a 1/4 of a second, there are pretty much set in stone theories about what the universe was like after
1x10^(-30)s.
Marcus, do you know if the total energy (not net) of the early universe would contribute to it's size in LQG? In other words, there is a limit to how small an arbitrary volume of the universe you can find, and this should limit the big bang initial size as wel. But if there is also a limit on the amount of curvature any given volume can have, wouldn't an increase in energy neccessarily increase the minimum volume as well?
