Planck results on the CMB, and latest on the Higgs

Planck CMB. Copyright ESA and the Planck Collaboration.

The Planck Collaboration released the most detailed map yet of the Cosmic Microwave Background (CMB), as measured by the European Space Agency’s (ESA) Planck satellite, along with an arXiv release of 30 submitted research articles analyzing the data. What boggles my mind is that as far as I’ve understood, these measurement represent pretty much the best possible data that can be obtained from the CMB, limited not by instrumentation but by fundamental quantum effects.

The Starts with a Bang blog gave a very good primer on what was expected from the data on the eve of the release, which I recommend reading before checking out the results. (See also Sean Carroll’s anticipatory post on his blog.) For the results, you can read the official press release by ESA, the story by Nature News, or head back to Starts with a Bang for an excellent recap of the results:

So yes to inflation, no to gravitational waves from it.

Yes to three very light, standard-model neutrinos, no to any extras.

Yes to a slightly slower-expanding, older Universe, no to spatial curvature.

Yes to more dark matter and normal matter, yes also to a little less dark energy.

It thus seems the results were not very unexpected, although the corrections to the energy balance and age of the universe were perhaps a bit more significant than was expected. See also Peter Woit’s take on the implications for string theory (spoiler: no support whatsover).


The Moriond CMS update of the Higgs→γγ search. Tantalizing hints of disagreement with the Standard model predictions are significantly reduced with the newer, larger dataset. From Résonaances.

The other breaking recent news came from the Moriond particle physics conference (it seems physicists have a good thing going with these skiing conferences, as I personally also know :), which saw the release of the latest data from teams working on the Higgs boson at the Large Hadron Collider. The Quantum Diaries presents the results thus:

No more Higgs-like, Higgs-ish or even Higgsy boson. The CMS and ATLAS collaborations, the two large experiments operating at the Large Hadron Collider (LHC) at CERN, have now gathered sufficient evidence to say that the new boson discovered last summer is almost certainly “a” Higgs boson. Note that we are going to call it “a” Higgs boson and not “the” Higgs boson since we still need more data to determine what type of Higgs boson we have found. But all the analysis conducted so far strongly indicates that we are indeed dealing with a type of Higgs boson.

In a nutshell: it’s a Higgs boson (as opposed to anything else), and in all likelyhood the Higgs boson (fully as predicted by the Standard Model of particle physics), with no anomalous properties or new physics still in sight. However, as stated in the press release, more data needs to be collected and analyzed before this is conclusive. Unfortunately due to the LHC shut-down, we will have to wait two years for new more stringent data.

For the most important plots of the data, see the viXra log, or the slides from the relevant talk at Moriond. For analysis of the agreement with the Standard model, see the Resonaances blog. Although many theoreticians are dismayed by the lack of any evidence for supersymmetry or other popular theories beyond the Standard model, there are some who think this is a good sanity check and will direct research to more fruitful directions.

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8 Comments on “Planck results on the CMB, and latest on the Higgs”

  1. Mark Robson says:

    Ethan (or anyone else) seems to unavailable to comment so perhaps you can answer my questions: Can you tell me which actual observation(s) or measurement(s) demonstrates that the distance between all galaxies increases over time to verify that the universe is expanding ?
    And I understood that the CMB contains no emission or absorption lines, so how is its redshift calculated ?

    • Toma says:

      I’m by no means an expert on the topic, but as far as I’ve understood, the expansion of the universe has been detected by observing the redshifts of Type 1a supernovas. Since their luminosity is known, their distances can be derived from their apparent brightnesses. And the finding is that the further away such a supernova is, the larger is its redshift, meaning the faster it is moving away from us. Since this is observed in all directions, the conclusion is that the universe is expanding.

      As for the CMB, it indeed contains no emission or absorption lines. The microwave background has a thermal black body radiation spectrum at a temperature of about 2.7 K. Since from atomic physics we know the threshold energy below which hydrogen atoms can form, we can estimate what the temperature of the universe was when it became transparent to radiation. Ever since then, the wavelength of the CMB photons has been increasing due to the expansion of the universe, causing them to redshift. So no emission or absorption is needed to calculate the redshift here.

      I hope these approximate answers were helpful to you!

      • Mark Robson says:

        Redshift itself does not demonstrate expansion of the universe or that the galaxy is moving away. Redshift is only a measure of distance. Now if a change (increase) in redshift has been recorded in a galaxy (or, rather several galaxies) over a certain period of time then this could indicate that the universe is expanding but as far as I know no such measurements have been recorded which is why I’m trying to find out if the assumption that the universe is expanding has been verified. And other explanations/interpretations for redshift have been published and it has not been proven that redshift is caused by expansion.
        You seem to be assuming more things here – which observation showed that the universe was NOT transparent to radiation ? And if you can’t actually calculate the redshift of the CMB, how do you know it has been redshifted, or by how much ? Why can’t the CMB be, say, 2 billion years old ?

        • Toma says:

          That’s not correct: redshift is a measure of VELOCITY, not distance – it’s an effect of Doppler shift (http://en.wikipedia.org/wiki/Doppler_effect). The distance measurement is independent of this and comes from the known intrinsic luminosity of supernovae.

          As for the transparency to radiation, this follows from atomic physics. If the temperature of a gas is higher than a certain very well known value, it is ionized and will not pass radiation (http://en.wikipedia.org/wiki/Big_Bang#Cosmic_microwave_background_radiation). And as I tried to explain, we CAN calculate the redshift of the CMB, since we can see that it is a blackbody spectrum. For such a spectrum there is a well-defined temperature, and the redshift is proportional to the difference between the temperature at the time of emission, and the current temperature (http://en.wikipedia.org/wiki/Cosmic_microwave_background_radiation#Relationship_to_the_Big_Bang).

          But I do not deny that other possible explanations for the redshift have been proposed (such as placing us at the center of a gigantic galactic void); they just don’t do as good a job explaining the measurements, and require assumptions that have not been supported by other data.

          • Mark Robson says:

            Well, this is exactly what I’m trying to confirm – how do you demonstrate that galaxies actually have a velocity without using the redshift? Supernova aren’t around for too long, but the luminosity of galaxies will be (approximately) constant, so if the galaxies are moving away then their luminosity will be decreasing over time – has this been measured ? And the angular size (diameter) of galaxies will also be decreasing over time if they are moving away – has this been measured ?
            I don’t know about galactic voids, but here is another explanation of redshift:
            ( http://www.newtonphysics.on.ca/hubble/index.html )

            • Toma says:

              I don’t think you can demonstrate their velocity otherwise, at least not for the further away ones that form the basis of the observation of expansion. Any decrease in luminosity would likely be way too small on human timescales to be measurable, as would be decrease of the angular size. Perhaps for some nearer objects these would be possible to measure, but I don’t remember hearing of such studies.

              But the Doppler shift if so well established from other kinds of measurements that it would take significant evidence to show that it wouldn’t apply here. And I’m sure there are other corroborating evidence, it’s simply just not my field. Newtonphysics doesn’t sound like a very credible source to me (there’s really no way of denying quantum physics), but I’ll check it out, thanks.

              • Roy Smith says:

                I think there were early estimates of the relative distances of galaxies using statistical analysis of angular size projected on the sky. As I understand it these correlated with redshifts. More recently Hubble data has provided information about apparent brightness of cepheid variables in relatively nearby galaxies and these have been used to calibrate the red-shift distance correlation. So as far as I know for galaxies the red-shift (ie recessional velocity) correlation with distance is secure.

                • Mark Robson says:

                  You are equating redshift with a recessional velocity but if you can’t show that the brightness diminishes over time or that the size (of galaxies) diminishes over time then how can you be sure that galaxies actually have a recessional velocity ?
                  Here is another explanation of redshift which doesn’t rely on unverified velocity:
                  ( http://www.lyndonashmore.com/preprintpdf.pdf )


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