The Universe through a lens, darkly…

Just time to post this neat picture I found on the BBC Website this morning:


Although these images were obtained using measurements of the cosmic microwave background made by Planck, they are not themselves maps of the radiation field itself. As photons produced in the early Universe travel through the Universe towards the observer, they are deflected by the gravitational field of intervening clumps of matter; this is called gravitational lensing. With a bit of effort this effect can be “inverted” to reveal the distribution of matter traversed by CMB photons, or at least a projection of that distribution along the line of sight. The good thing about this is that the maps show all the matter (through its gravitational effects) not just the luminous part that might be seen in a galaxy surveys, so they might provide more direct ways of testing cosmological theories.

23 Responses to “The Universe through a lens, darkly…”

  1. How do we say CMB at three kelvin when after bang it is transition from plasma to early atoms. What is the calculation if we can understand.

  2. Expansion is less than speed of light ,where as photons travel at speed of light. How we understand this. What actually expands exponentially before CMB . Nothing to give gravitional lensing.

  3. A factor of few trlillions before CMB we call exponential inflation–a few times speed of light and may be a factor of 1000 since CMB , and a clear violation of conservation of energy and relativity and the mechanism is unknown. The blackbody distribution from 3000k to 3k can not be very basic physics. We have to study in details. How it is 3000k is not clear but may be some more thinking on basic physics may be necessary. Anyway I may not be aware. But I am looking into some materials in the internet . Thanks.

  4. It can be cold big bounce instead of hot big bang.

    • My balloon inside balloon theory of matter and antimatter universe on opposite entropy path predicts cold big bounce at tends to zero kelvin of matter universe and tends to zero entropy of antimatter universe due to un equilibrium causing the bounce and huge force of entropy of the matter universe will be the mechanism of Dr.Guth exponential inflation with a break at CMB at three kelvin with normal dark energy expansion etc. So I was intersested to see a report on cold big bounce instead of hot big bang.

      • Normally when a theory predicts one thing and one observes another, one rejects the theory as wrong and moves on.

      • …true – but that stop Omega=1 CDM models (at least for ~20 years?)

      • Yes, Cold Big Bounce can not be ruled out.

      • “…true – but [did ]that stop Omega=1 CDM models (at least for ~20 years?)”

        For those who believed the data, there was no faith in Omega=1: Coles and Ellis, Carlberg, myself, many others. Yes, Rocky Kolb was still hanging on to EdS as late as 2000 or so. Maybe he still is. I don’t know if Allan Sandage ever lost faith in EdS. (He dedicated his life to trying to determine this observationally but, at least in his later years, presumed he knew the answer.)

        To be fair, in the 1970s and 1980s, while there was never any evidence in favour of Omega=1, it couldn’t be completely ruled out, but by the early 1990s this was looking difficult to reconcile with observations. However, only the brave considered the cosmological constant then.

      • “Yes, Cold Big Bounce can not be ruled out.”

        Give us something which, if observed, would rule it out. If you can’t, then it is not a scientific theory.

      • Dr.Roger Penrose declared physics wrong and searching the bounce circles and found some . So my theory is being taken a possibility.

      • telescoper Says:

        That paper was completely wrong.

      • Even apart from the facts that the Penrose paper which you mentioned was criticized by many and that Penrose himself has now distanced himself somewhat from it, he was never considering your theory.

        By the way, what is the point in linking to an inactive, essentially empty blog?

  5. Yes, his considerations was a BIG RIP idea and I told him long back to see if my theory is more appropriate . Dr,Stephen Hawking is now advising to look into M-theory ideas in Planck map. My theory of course little different from M-theory . It is better to look into various possibilities and nothing is declared absolute wrong but there are many opinions.

  6. Shantanu Says:

    Phillip, what is Eds?

    • Bryn Jones Says:

      Einstein-de-Sitter model (Omega_M = 1, Omega_Lambda = 0, zero pressure). I had to think about what the acronym meant for a moment too.

      • Right. Sorry for the jargon. 😐 I had to think about what Eds meant, but EdS is clear. 🙂

      • Bryn Jones Says:

        EdS is clear to cosmologists; but as someone with a background in extragalactic astrophysics, not cosmology, I had to think about it for a few seconds!

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