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Planck satellite, gravitational waves

  1. Aug 1, 2012 #1
    Has the Planck satellite observed any gravitational waves yet? I'm pretty sure that gravitational waves were formed when gravity split from the other forces at 10^-43 seconds but I could be wrong. Anyhow, if we do detect them, will we be looking at the first Planck time in our universe's history?

    Here's a quote from Peter Woit that leads me to believe this:

  2. jcsd
  3. Aug 1, 2012 #2


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    One idea being kicked around is that the imprint of gravitational waves might be seen on the CMB. Cosmic Microwave Background. Hugely enlarged by the expansion that has occurred since the CMB light was emitted.

    There are several dozen papers written about this. It gets studied and discussed a lot.

    Gravity waves would have caused DENSITY FLUCTUATIONS in the hot gas whose light we see as CMB.
    These density fluctuations (large and small depending on the mix of gravity wavelengths) would
    result in very slight TEMPERATURE FLUCTUATIONS.
    The waves' imprint would be mapped by mapping both the slight temperature variation and the POLARIZATION of the light.

    So by making very detailed maps of the CMB there is a chance to see what the mix of gravity wave was in early universe.

    But I can't say how far back. I can't say an exact figure like 10-43 seconds.
    First let us see what is in the Planck skymaps and then let us talk about when the fluctuations originated.

    the main job of Planck is to map the CMB more finely than the earlier space missions (COBE, WMAP) were able to.
    Last edited: Aug 1, 2012
  4. Aug 2, 2012 #3

    Planck will release its cosmology data most likely in Jan 2013. So if this discovery is made it wont be out to the public until then.
    I have spoken to some people on Planck and they dont rate its chances of doing this, most likely it will take a mission like this:


    However we can always hope for a pleasant suprise from Planck
  5. Aug 2, 2012 #4


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    At very least, Planck should resolve some of the goofy issues derived from the WMAP data. It would be nice if we could tease out more polarization data, but, that may be too optimistic. I'm unreasonably confident it will provide us with surprises - which probably means significant delays in public release.
  6. Aug 2, 2012 #5
    On the FQXI podcast there was an interview with one of the cosmologists compiling data for release and she said Jan 2013, but of course that can change. It has definitley finsihed its data collection mission.
  7. Aug 2, 2012 #6


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    Unfortunately I believe the COrE proposal was scrapped. But yes, we would have to be very, very lucky to see the B-mode polarization (the part that is mostly produced by gravity waves) with Planck. The main problem is that theoretically, it is entirely conceivable for the B-mode level to be ten or a hundred times smaller than Planck could ever detect.
  8. Aug 2, 2012 #7


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    Actually, while the coolant ran out for HFI (high-frequency instrument) earlier this year, LFI (low-frequency instrument) continues to take data:
  9. Aug 2, 2012 #8
    I didnt know COre was scrapped , any link that confirms that? I guess in the current funding eviroment it wasnt very likely anyway. Do you think any ground based experimetns have much of a chance? It seems a dedicated space based mission could be a decade or more away.

    I shoudl have said its finsihed its primary mission sorry
  10. Aug 2, 2012 #9


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    The COrE website is here:

    ...where they mention that their satellite was a proposal for ESA Cosmic Vision 2015-2025. The candidate missions for that have now been selected, and don't include COrE:

    Edit: I should mention that at some point, I do expect we will see something like COrE, at least in terms of capability. But my guess is that the motivation for something like this will become much stronger if B-waves are detected via ground-based or balloon-based experiments, which are collecting better and better data all the time.
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