Planck, Pointillism and the Axle of Elvis

The reason I was out of the office yesterday was that I was in Cambridge, doing a PhD oral in the Cavendish Laboratory so the first thing to say is congratulations Dr Johnston! It was one of those viva voce examinations that turned out to be less of an examination than an interesting chat about physics. In fact the internal examiner, Prof. Steve Gull, seemed to spend more time asking me questions rather than the candidate!

Afterwards I met up with Anthony Lasenby, the candidate’s supervisor. Not surprisingly the main topic of our brief discussion was today’s impending announcement of results from Planck. Anthony is one of the folks who have been involved with Planck for about twenty years, since it began as a twinkle in the eye of COBRAS/SAMBA. I was looking forward to getting in bright and early this morning to watch the live streaming of the Planck press conference from Paris.

Unfortunately however, I could feel a bit of a lurgy coming on as I travelled to Cambridge yesterday. It got decidedly worse on the way home – it must have been the Cambridge air – and I even ended up passing out on the train from Victoria to Brighton. Fortunately, Brighton was the terminus so someone woke me up when we got there and I got home, coughing and spluttering. I suspect many cosmologists didn’t sleep well last night because of excitement about the Planck results, but in my case it was something else that kept me awake. Anyway, I didn’t make it in this morning so had to follow the announcements via Twitter. Fortunately there’s a lot of press coverage too; see the ESA site and a nice piece by the BBC’s redoubtable Jonathan Amos.

Anyway, without further ado, here’s Planck’s map of the cosmic microwave background:


It’s rather beautiful, in a pointillist kind of way, I think…

It will take me a while in my weakened state to complete a detailed study of the results – and I’m sure to return to them many times in the future, but I will make a couple of points now.

The first is that the papers and data products are all immediately available online. The papers will all appear on the arXiv. Open Access sceptics please take note!

The second is that the most interesting result (as far as I’m concerned) is that at least some of the cosmic anomalies I’ve blogged about in the past, such as the Axle of Elvis Axis of Evil and the famous colder-than-it-should-be cold spot, are still present in the Planck data:


The other results excite me less because, at a quick reading, they all seem to be consistent with the standard cosmological model. Of course, the north-south asymmetry is a small effect on could turn out to be a foreground (e.g. zodiacal emission) or an artefact of the scanning strategy. But if it isn’t a systematic it could be very important. I suspect there’ll be a rush of papers about this before long!

I’m sure to p0st much more about the Planck results in due course, but I think I’ll leave it there for now. Please feel free to post comments and reactions through the box below.

22 Responses to “Planck, Pointillism and the Axle of Elvis”

  1. The resolution is fine 🙂 but I am missing the green color a bit 😦
    The palette now looks more like red-yellow spots on blue background. I wonder if the painter could rescale it to make the colors less irritating? (joke)

    • I think the idea was to have a “neutral” color (white, black or grey) around zero, to clearly separate positive and negative values. This works for the CMB, but less well for things like catalogs of sources, etc. I believe there is still another color scheme for that.

  2. Bryn Jones Says:

    Remind us how much Planck cost, again.

    (It was probably worth it, although that money could have been used for other things, such as running facilities in other fields within astronomy, or creating a sustainable careers system for European astronomers.)

  3. My initial understanding – after a very quick scan of the papers – is that Planck do account for foreground contaminations from zodiacal emission, which WMAP didn’t do, and that therefore the explanation for these large-scale anomalies probably doesn’t lie there.

    • telescoper Says:

      Yes, but is their model right?

      • At least it is probably better than WMAP’s model! 🙂 (The real answer is, I have no idea.)

      • I agree with what Hans Kristian Eriksen says below about the relevance of zodi to the features, but to answer your question about the model itself: It’s certainly not perfect. It’s an extrapolation of what was done for COBE/DIRBE. It had issues for DIRBE, and given differences in wavelength and angular resolution, necessarily has issues for Planck as well.

  4. Hans Kristian Eriksen Says:

    Quick comment: Zodiacal light is not a particular good candiate for explaining this asymmetry, for at least four reasons. First, the signature is frequency indepedent, as far as we are able to measure, at least between 61 and 217 GHz (considering both WMAP and the recent Planck analyses), while the zodi has a dust-like spectrum. Second, and perhaps equally important, the zodi has a very clear quadrupolar structure on the sky, by virtue of following the ecliptic plane — it’s very, very difficult to explain a dipole-type effect with the zodi. Third, with the recent Planck data, the power asymmetry is in fact seen up to l=1500, not just at large angular scales, although the relative amplitude is lower at high l’s than at low l’s. The preferred axis is very stable, though.

    Fourth, concerning the “alignment” with the ecliptic, I personally don’t think this is very striking, to say the least. Table 23 in the Planck Isotropy paper shows that the typical direction, although varying slightly with angular scale and data set, is Galactic coordinates (l,b) = (227,-15), which corresponds to ecliptic coordinates of (97, -42) degrees. That is, the distance from that point to the Ecliptic South Pole is 48 degrees. If one considers a 48 degree alignment as suspicous, and then would be suspicous of, say, the Galactic poles and the Galactic center as well, due to foregrounds, not much of the sky is left. So, personally, I think this common idea that this effect is aligned with the ecliptic, which in fact even was stated at the Planck press conference today (!), is due to the fact that people are not very good at doing spherical trigonometry in their head directly from a Mollweide projection map (but knowing that the SEP is “roughly down there”), rather than hard numbers.

    • Hans Kristian Eriksen Says:

      Actually, I see that I should have written “61 to ~217 GHz” above — while separate analyses were done for each frequency band for WMAP in earlier papers, only the four foreground cleaned Planck maps were considered in the current Planck paper. However, these employ different frequencies in their reconstructions, and weight different frequencies differently with l, with more weight on the high-frequency channels at high l’s. So the cleaned Planck CMB maps are essentially a gliding weighted average between ~70 and 217 GHz. The fact that we see the asymmetry in all of them, over all l’s, and for individual WMAP frequencies therefore imply that it’s present between 70 and 217 GHz. So, foregrounds are unlikely to explain this, given this stability in frequency and scale. The statistical significance is a more delicate question, as it depends on whether people are impressed with ~3-3.5 sigma effects or not. The problem now, though, is that there is starting to be a considerable number of those ~3sigma effects. If a sensible theoretical model can be established that is able to explain several of these at once, those significances would obviously go up very quickly.

  5. There is a nice compact source catalogue. Much more likely to have surprises ! Also, Andrew Liddle gave us a seminar today and told us about the SZ results, which seem to disagree with the CMB results.. So could get interesting. You will note I am resisting more comments about George’s tie.

  6. Shantanu Says:

    Just a comment on the paper about constraints on inflation (regarding references)

    Click to access Planck_2013_results_22.pdf

    Would have been nice if Demos Kazanas’ 1980 paper was cited (as it was the first one which mentioned that accelerated expansion could solve the horizon problem) Kazanas paper is referenced in one of the other papers, so I am surprised its not included in a paper on inflation.

  7. […] Peter Coles’ In the Dark […]

  8. I think it is better to say axle of Elvis . I do not agree with axis of evil. This observation along with polarization studies may hint some thing beyond standard model Many other areas of science also giving us some indication to change or modify our ideas and we can go accordingly in open mind. Durgadas Datta said that re bounce occured at tends to zero entropy at tends to zero kelvin in his balloon inside balloon theory and visibility we are seeing in the map is at three kelvin as per his calculations. The inflation mechanism is entropical huge bounce . This can be discussed with Professors at Cambridge .

  9. It is possible that bounce occured when antimatter universe was tends to zero entropy and matter universe was tends zero kelvin. This instability has given Dr.Guths inflation.

  10. The “Axis of Evil” is still there. The Copernican Principle is now compromised if not completely defunct. Of course, rather than consider a small earth centered universe, science will come up with a 57 dimensional theory to explain away the observations.

  11. James P Says:

    Thanks John Q. I, for one, am really looking forward to seeing the upcoming scientific documentary The Principle and am glad that one can sign up for updates at From what I’ve heard through the grapevine this movie is really going to set the scientific community reeling since it will be presenting the latest and rapidly growing amount of scientific evidence indicating in no uncertain terms that for the last 400 years plus scientists have allowed themselves to accept the Copernican Principle as fact when in fact it is utterly false!

  12. […] has made me rather late in getting around to reading the papers released by the Planck consortium a couple of weeks ago. I’ve had a bit of time this Sunday so I decided to have a look. Naturally I went straight […]

  13. […] made me rather late in getting around to reading the papers released by the Planck consortium a couple of weeks ago. I’ve had a bit of time this Sunday so I decided to have a look. Naturally I went straight for, […]

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