The Planck Collaboration Opens The Kimono

Hot on the heels of the Moriond Conference (during which CERN officials announced that they are confident that the Higgs-like boson announced last July 4 is, in fact, a Higgs boson), the ESA’s Planck Collaboration have plopped out 30 papers announcing the results thus far of the Planck Satellite’s examination of the Cosmic Microwave Background (CMB), the cosmic “afterglow” of the Big Bang, discovered back in 1964 by Arno Penzias and Robert Wilson.

Cosmic Microwave Background (Image credit: ESA, Planck Collaboration)

Capturing the CMB at even higher resolution than the WMAP mission, Planck’s data have allowed the team to produce a refined plot of the CMB fluctuation angular power spectrum, including values for multipole moment l>1000 (for which WMAP had no solid data), corresponding to smaller angular features. (E.L. Wright has a great tutorial on the CMB power spectrum.)

Power spectrum of temperature fluctuations. (Image credit: ESA and the Planck Collaboration)

While I haven’t really had a chance to dive in, there are a lot of goodies here. In summary:

• The data refines estimates of the age of the universe to 13.82 billion years. Estimates based upon WMAP data pegged this at 13.73 billion years.
• The Planck data indicates a Hubble constant (the rate at which the universe is expanding) of 67.3 kilometers per second per megaparsec, slightly lower than the previously estimated value of 74.2 km/s/Mpc. (This constant is a tricky beast to measure accurately, but that is a story for another day.)
• Estimates of the composition of the universe are a bit different from those obtained from WMAP data as well:
  • 4.9% baryonic (normal) matter – up from 4.6% from WMAP data
  • 26.8% dark matter – up from 24% from WMAP data
  • 68.3% dark energy – down from 71.4% from WMAP data
• An anisotropy in the CMB observed in WMAP is confirmed. One side of the CMB is a bit warmer on average, and the opposite side is a bit cooler. It is a subtle effect, but it is there. This could have profound implications for the generally accepted assumption in cosmological models of isotropy. Or, it could be a statistical fluke. Unfortunately, we only have a sample size of one universe, so it is difficult to tell based upon the available data. (Here is something that Sean Carroll wrote about this anisotropy in 2008.)
• In the power spectrum, there seems to be some suppression of fluctuations at large angular scales. (In other words, there are non-Gaussian deviations in the distribution of fluctuations.) This could help refine inflationary models.
• N_eff has a measured value of 3.3 ±0.5, consistent with Standard Model predictions assuming only three neutrino species. This dampens hopes for the discovery of sterile neutrinos (neutrinos which do not interact via the weak nuclear force), despite recent results from the MiniBooNE experiment hinting at the possibility of sterile neutrinos. (This result means that I’ll have to update several sections of the neutrino physics “mega-post” that I’ve been working on for over a year. Will I ever finish that bloody thing?)

As I have already indicated, I haven’t really had time to dive in, but there are plenty of others commenting on this.  Here are some of the best sources:

• ESA Science & Technology: Simple but challenging: the Universe according to Planck
• Planck Published Papers
• NASA – Planck
• The Universe According to Planck (The Satellite) | Of Particular Significance
• What The Entire Universe Is Made Of, Thanks to Planck! – Starts With A Bang
• RÉSONAANCES: The universe after Planck (The best line in any of this commentary: “They find Neff=3.3±0.5, that is no hint of anything interesting going on. The gurgling sound you hear behind the wall is probably your colleague working on sterile neutrinos committing a ritual suicide.”)
• Planck results: our weird and wonderful Universe | Galileo’s Pendulum
• Walking the Planck: Our Lopsided Universe | Cocktail Party Physics, Scientific American Blog Network
• Age of the universe: Planck results show universe is 13.82 billion years old.
• Planck telescope peers into the primordial Universe : Nature News & Comment
• BBC News – Planck satellite: Maps detail Universe’s ancient light

Background material on the CMB:

• CMB Introduction (Summary)
• CMB Introduction (Power Spectrum)
• CMB Review (CMB Temperature Field)
• The CMB angular power spectrum
• Ned Wright’s Cosmology Tutorial
• Theoretical Overview of Cosmic Microwave Background Anisotropy – E.L. Wright
• www.damtp.cam.ac.uk/user/db275/Cosmology/Chapter7.pdf
• physics.gmu.edu/~joe/PHYS428/Topic11.pdf
• Healpy tutorial — healpy 1.6dev documentation (illustrating techniques for visualization of CMB data)
• Cosmic Microwave Background Analysis Tools: COMBAT (more software tools)
• LAMBDA – Legacy Archive for Microwave Background Data
• LAMBDA – CMB Toolbox Overview