Tom Ashbrook at Boston’s WBUR does a terrific job interviewing Neil Turok (Cambridge University) and Alan Guth (MIT) on an issue dear to them both: the Big Bang. Did it occur as advertised, or are new ways of looking at the question through the lens of string theory changing everything? How has the inflation model developed over the years, and did the Big Bang mark the beginning of time? Here’s an interview excerpt from Turok:
“I think the challenge we’re raising is that the usual picture of the Big Bang is based on an assumption which is that time, space, matter, energy, everything began at the Big Bang. And that assumption was made in the 60s when people got the first strong observational evidence that the Big Bang happened. But it’s really just an assumption and our point of view has come out of new development in physics which are enabling us to describe the behaviour of matter in very extreme conditions such as were present around the Bang. And what we’re seeing is that the Big Bang doesn’t have to be the beginning of time. It’s perfectly possible that the Big Bang was just a violent event in a pre-existing universe.”
This is lively and controversial stuff indeed, and I’ve seldom heard the issues laid out so clearly. The entire, hour-long interview is available here and is well worth your time. Barnard College’s Janna Levin also offers valuable insights, and excerpts from her book How the Universe Got Its Spots (Princeton, 2002) and Turok and Paul Steinhardt’s new title Endless Universe (Doubleday, 2007) are available on the site.
C.E. 100 Billion: Big Bang Goes Bye-Bye
Cosmic expansion may leave astronomers of the far future with no hint of the big bang that started it all
By JR Minkel
Pity the poor astronomers living in our galaxy 100 billion years from now, for they will detect neither hide nor hair of the big bang that kicked off the known universe. Researchers say that the runaway expansion of the cosmos by then will have blown away all evidence of the big bang like dandelion fluff into the wind. With it will go cosmology, the study of the origin and evolution of the universe. But before getting too smug, be aware that we also may not be privy to long lost evidence of other mysteries.
http://www.sciam.com/article.cfm?chanId=sa013&articleId=C420F7DE-E7F2-99DF-3E47CE32FD4AD465
I wonder, might it be possible for some intelligence in the far distant future to create a big bang? I know science claims matter/energy can be neither created nor destroyed, but matter for the existing universe had to come from somewhere. Might it be possible for some civilization with a trillion trillion years of science behind them to simulate those conditions and for each island universe to become the seed for a whole new expanding universe?
Has anything come of the conjecture that our Big Bang was the result of a collision between our spacetime and an adjacent universe? It’s a cool idea that was floating around a few years back, though I haven’t heard much about it since.
Hi Chris
Neil Turok was one of the co-developers of the “clashing branes” theory you’re talking about. It had a few problems which he and Paul Steinhardt have worked on since then.
I personally reject the Infinite Time cosmos they’re describing for several reasons, but the main one is the fate of intelligent life….
[from a post to “The Habitable Zone”…]
Any infinite Universe means that Life and Mind must go extinct in EVERY cosmic cycle or else in infinite time the Universe would be totally shaped by intelligent activity and remain so.
Since this sub-section of the Infinite hasn’t been shaped by Mind then it must all be destroyed eventually before the next Cycle – Death reigns triumphant in a Cyclic cosmos. Shiva rules, not Brahma or Vishnu.
Personally I find that utterly depressing as a cosmology and really couldn’t be bothered with it. An Infinite-Time Universe I could accept would be like the one depicted in Stephen Baxter’s “The Time Ships” (the official sequel to H.G.Wells’ “The Time Machine”) – the Infinite is shaped and guided by Mind from infinity to infinity.
[end extract]
One point unanswered in Baxter’s fiction is just where the energy comes from to sustain an infinite cosmic time that has no beginning. A similar problem means that in the Infinite Cyclic Universes large regions empty out and hit an entropic maximum, then new energy and matter is “stretched” out of the vacuum anew. The Universe expands to Infinity endlessly, but regions of useful energy are but brief flashes in a vast, cold void.
Adam
Maybe our Universe was formed from an accident with
someone else’s version of the Large Hadron Collider….
I came across this thread while trying to find/remember the name of a book/story from my childhood. It is reminiscent of the question asked by David:
Quote:
david Says:
June 5th, 2007 at 18:47
I wonder, might it be possible for some intelligence in the far distant future to create a big bang?
/Quote
A man creates a time machine and uses it to travel back to see the big bang. As he pops, it is this act that introduces matter into the void, creating the big bang. Can’t remember the name of it, but it is an interesting idea.
Ralph Alpher: 1921 – 2007
Forgotten father of Big Bang dies
http://physicsworld.com/cws/article/news/30915
Does string theory predict an open universe?
Authors: R. Buniy, S. Hsu, A. Zee
(Submitted on 20 Oct 2006 (v1), last revised 7 Jan 2008 (this version, v2))
Abstract: It has been claimed that the string landscape predicts an open universe, with negative curvature. The prediction is a consequence of a large number of metastable string vacua, and the properties of the Coleman–De Luccia instanton which describes vacuum tunneling. We examine the robustness of this claim, which is of particular importance since it seems to be one of string theory’s few claims to falsifiability. We find that, due to subleading tunneling processes, the prediction is sensitive to unknown properties of the landscape. Under plausible assumptions, universes like ours are as likely to be closed as open.
Comments: 4 pages, 1 figure, revtex. Final version to appear in Physics Letters B
Subjects: High Energy Physics – Theory (hep-th); Astrophysics (astro-ph); High Energy Physics – Phenomenology (hep-ph)
Cite as: arXiv:hep-th/0610231v2
Submission history
From: Stephen D. H. Hsu [view email]
[v1] Fri, 20 Oct 2006 23:05:32 GMT (19kb)
[v2] Mon, 7 Jan 2008 02:52:04 GMT (21kb)
http://arxiv.org/abs/hep-th/0610231
Dangerous Angular KK/Glueball Relics in String Theory Cosmology
Authors: J.F. Dufaux (Madrid, Autonoma U.), L. Kofman (Canadian Inst. Theor. Astrophys.), M. Peloso (Minnesota U.)
(Submitted on 20 Feb 2008)
Abstract: The presence of Kaluza-Klein particles in the universe is a potential manifestation of string theory cosmology. In general, they can be present in the high temperature bath of the early universe. In particular examples, string theory inflation often ends with brane-antibrane annihilation followed by the energy cascading through massive closed string loops to KK modes which then decay into lighter standard model particles. However, massive KK modes in the early universe may become dangerous cosmological relics if the inner manifold contains warped throat(s) with approximate isometries. In the complimentary picture, in the AdS/CFT dual gauge theory with extra symmetries, massive glueballs of various spins become the dangerous cosmological relics. The decay of these angular KK modes/glueballs, located around the tip of the throat, is caused by isometry breaking which results from gluing the throat to the compact CY manifold.
We address the problem of these angular KK particles/glueballs, studying their interactions and decay channels, from the theory side, and the resulting cosmological constraints on the warped compactification parameters, from the phenomenology side. The abundance and decay time of the long-lived non-relativistic angular KK modes depend strongly on the parameters of the warped geometry, so that observational constraints rule out a significant fraction of the parameter space.
Comments: 58 pages, 11 figures
Subjects: High Energy Physics – Theory (hep-th); Astrophysics (astro-ph); High Energy Physics – Phenomenology (hep-ph)
Report number: IFT-UAM/CSIC-07-66, UMN-TH-2637/08
Cite as: arXiv:0802.2958v1 [hep-th]
Submission history
From: Lev Kofman [view email]
[v1] Wed, 20 Feb 2008 22:44:29 GMT (70kb)
http://arxiv.org/abs/0802.2958
Matter sources for a Null Big Bang
Authors: K.A. Bronnikov, O.B. Zaslavskii
(Submitted on 30 Oct 2007 (v1), last revised 10 Mar 2008 (this version, v2))
Abstract: We consider the properties of stress-energy tensors compatible with a Null Big Bang, i.e., cosmological evolution starting from a Killing horizon rather than a singularity. For Kantowski-Sachs cosmologies, it is shown that if matter satisfies the Null Energy Condition (NEC), then (i) regular cosmological evolution can only start from a Killing horizon, (ii) matter is absent at the horizon, and (iii) matter can only appear in the cosmological region due to interaction with vacuum. The latter is understood phenomenologically as a fluid whose stress tensor is insensitive to boosts in a particular direction. We also argue that matter is absent in a static region beyond the horizon. All this generalizes the observations recently obtained for a mixture of dust and a vacuum fluid.
If, however, we admit the existence of phantom matter, its certain special kinds (with the parameter $w \leq -3$) are consistent with a Null Big Bang without interaction with vacuum (or without vacuum fluid at all). Then in the static region there is matter with $w\geq -1/3$. Alternatively, the evolution can begin from a horizon in an infinitely remote past, leading to a scenario combining the features of a Null Big Bang and an emergent universe.
Comments: 5 two-column pages, revtex4, no figures. Substantially reworked
Subjects: General Relativity and Quantum Cosmology (gr-qc); Astrophysics (astro-ph); High Energy Physics – Theory (hep-th)
Cite as: arXiv:0710.5618v2 [gr-qc]
Submission history
From: Kirill Bronnikov [view email]
[v1] Tue, 30 Oct 2007 11:51:43 GMT (8kb)
[v2] Mon, 10 Mar 2008 19:39:03 GMT (11kb)
http://arxiv.org/abs/0710.5618
Hints of structure beyond the visible universe
New Scientist news service June 10, 2008
Colossal structures larger than the
visible universe — forged during
the period of cosmic inflation
nearly 14 billion years ago — may
be responsible for a strange pattern
seen in the big bang’s afterglow,
says a team of cosmologists. If
confirmed, the structures could
provide precious information about
the universe’s earliest…
http://www.kurzweilai.net/email/newsRedirect.html?newsID=8851&m=25748