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Cosmic Inflation: Evidence and Perspective

I want to talk about an exciting project to find traces of cosmic inflation today, but first, a bit of housekeeping. Regulars will know that server issues a couple of weekends ago caused me to change the software this site uses to a temporary WordPress theme while I worked to install a more permanent solution. The new look is now in place, with a wider page, changes in fonts and, behind the scenes, all kinds of useful tools that will make maintaining and upgrading Centauri Dreams a far less arduous proposition.

The new server configuation seems stable as well, so I’m hopeful that those recent issues are past us. No Web site is ever complete, and I have numerous tweaks to phase in over the coming months, but having a stable platform is obviously the first task.

Now, to that inflation story. Over the weekend at the American Physical Society meeting in Denver, Ki Won Yoon (National Institute of Standards and Technology) described an experimental collaboration that is using incredibly sensitive microwave detectors to take us ever deeper into the cosmic microwave radiation. We’ve gone a long way toward measuring the CMB’s temperature, looking at the slight variations that existed some 380,000 years after the Big Bang and shaped today’s cosmos.

Called the Atacama B-mode Search, the new experiment will probe the early universe using these enhanced detectors to pull yet further information out of the primordial CMB signal. What the researchers are looking for is the signature of gravitational waves, evidence for which may be found in their imprint on the direction of the CMB’s electric field. That signature, called B-mode polarization, has yet to be confirmed, but the new experiments may be able to find it, thus offering support to inflation concepts. “A detection of primordial gravitational waves through CMB polarization,” says Ki Won Yoon, “would go a long way toward putting the inflation theory on firm ground.”


Image: What we observe of the Cosmic Microwave Background emerged 380,000 years after the Big Bang. Patterns imprinted on this light encode the events that happened only a tiny fraction of a second after the Big Bang. In turn, the patterns are the seeds of the development of the structures of galaxies we now see billions of years later. B-mode polarization may tell us whether current thinking about inflation explains what we see. Credit: NASA / WMAP Science Team.

This would be quite a find, and one pushing our detection methods to the limit, given that B-mode polarization signals may be a million times fainter than the temperature changes we’ve studied thus far. It would give us insights into a process by which spacetime itself seems to have expanded all but instantaneously from subatomic size, and might also offer clues about different models of string theory and other unified theories of physics. The arrays to do all this will be mounted on a telescope in the Chilean desert approximately a year from now.

What bracing times for cosmology as we probe ever deeper into the CMB. From our propulsion perspective, cosmic inflation is a reminder that spacetime itself is not affected by the speed of light limitation that constrains objects moving through it. This is the foundation of the Alcubierre ‘warp drive’ concept, which manipulates spacetime in front of and behind the starship but does not violate Special Relativity. Such a feat may or may not ever be achieved, but confirming inflation would show us that the cosmos, at least, has figured out how to do it.

Comments on this entry are closed.

  • webjones May 4, 2009, 20:02

    Responding to the housekeeping portion of the post – nice updates and good navigation improvements. You might consider devoting a page with a navigation tab to the links that are now way down on the bottom of the right panel.

  • Administrator May 5, 2009, 10:22

    webjones, good idea. Let me see what I can do.

  • philw1776 May 5, 2009, 15:27

    “A detection of primordial gravitational waves through CMB polarization,” says Ki Won Yoon, “would go a long way toward putting the inflation theory on firm ground.”

    Such falsifiable predictions make Cosmic Inflation a more credible theory. Now if we could only find evidence of the cosmic “Stimulus Package” that initiated the Big Bang!

  • Rick S. May 7, 2009, 9:55

    Vaguely formed idea. Did the energy of the universe drive the expansion or did the expansion create the energy? If the universe initially inflated at at rate faster than light then there would be a Black Horizon, or event horizon that spanned the universe’s boundary. According to Prof. Hawking’s theory an event horizon emits radiation, the amount of which is inversely dependent on the area of that horizon. This being said very close to the time of the ‘big bang’ the black horizon’s area was extremely small and thus could emit copious amounts of radiation. This radiation would be emitted into the interior and trapped within the rapidly expaning space.

  • ljk May 23, 2009, 17:39

    The Big Bang as the Ultimate Traffic Jam

    Authors: Vishnu Jejjala, Michael Kavic, Djordje Minic, Chia-Hsiung Tze

    (Submitted on 18 May 2009)

    Abstract: We present a novel solution to the nature and formation of the initial state of the Universe. It derives from the physics of a generally covariant extension of Matrix theory. We focus on the dynamical state space of this background independent quantum theory of gravity and matter, an infinite dimensional, complex non-linear Grassmannian. When this space is endowed with a Fubini–Study-like metric, the associated geodesic distance between any two of its points is zero. This striking mathematical result translates into a physical description of a hot, zero entropy Big Bang.

    The latter is then seen as a far from equilibrium, large fluctuation driven, metastable ordered transition, a “freezing by heating” jamming transition. Moreover, the subsequent unjamming transition could provide a mechanism for inflation while rejamming may model a Big Crunch, the final state of gravitational collapse.

    Comments: 8 pages, This essay received an honorable mention in the Gravity Research Foundation Essay Competition, 2009

    Subjects: General Relativity and Quantum Cosmology (gr-qc); High Energy Physics – Theory (hep-th)

    Report number: IHES P/09/23, VPI-IPNAS-09-04

    Cite as: arXiv:0905.2992v1 [gr-qc]

    Submission history

    From: Michael Kavic [view email]

    [v1] Mon, 18 May 2009 22:03:45 GMT (11kb)


  • ljk August 6, 2009, 11:07

    Perspectives in cosmology

    Authors: Alexander Vilenkin

    (Submitted on 5 Aug 2009)

    Abstract: The “new standard cosmology”, based on the theory of inflation, has very impressive observational support. I review some outstanding problems of the new cosmology and the global view of the universe — the multiverse — that it suggests. I focus in particular on prospects for further observational tests of inflation and of the multiverse.

    Comments: Invited talk at TAUP conference, Rome, July 2009

    Subjects: Cosmology and Extragalactic Astrophysics (astro-ph.CO)

    Cite as: arXiv:0908.0721v1 [astro-ph.CO]

    Submission history

    From: Alexander Vilenkin [view email]

    [v1] Wed, 5 Aug 2009 18:25:41 GMT (8kb)


  • ljk August 18, 2009, 11:16

    Why the Initial Infinite Singularity of the Universe is Not There

    Authors: Marcelo Samuel Berman

    (Submitted on 20 Apr 2009 (v1), last revised 16 Aug 2009 (this version, v2))

    Abstract: We “explain”, using a Classical approach, how the Universe was created out of “nothing”, i.e., with no input of initial energy. This is a Universe with no-initial infinite singularity of energy density.

    Comments: International Journal of Theoretical Physics, 48, 2253-2255(2009)

    Subjects: General Physics (physics.gen-ph)

    Journal reference: Int.J.Theor.Phys.48:2253-2255,2009

    DOI: 10.1007/s10773-009-0007-0

    Cite as: arXiv:0904.3143v2 [physics.gen-ph]

    Submission history

    From: Marcelo Samuel Berman [view email]

    [v1] Mon, 20 Apr 2009 23:54:22 GMT (4kb)

    [v2] Sun, 16 Aug 2009 14:13:12 GMT (4kb)