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First Cosmological Results From MAP

Posted by michael on from the profoundest-act-of-worship dept.

riptalon writes "The Wilkinson Microwave Anisotropy Probe, a NASA Explorer mission has announced the first results based on a year of observations from the L2 Lagrangian point. MAP carries two back-to-back microwave telescopes to study variations in the cosmic microwave background, to much greater accuracy than the COBE satellite. The excruciating details of the results on the age, geometry and composition of the universe can be found in this paper. Executive summary: 13.7 billion years old, flat, 4.4% baryons, 22% dark matter and 73% dark energy."

4 of 291 comments (clear)

  1. huh? by dirvish · · Score: 3, Interesting

    Anyone care to let us non-space nerds know what baryons, dark matter and dark energy are? TIA.

    --
    FoundNews.com - get paid to blog.,
    1. Re:huh? by adminispheroid · · Score: 3, Interesting

      You missed the part where he said "in astronomy." In astronomy, a lot of wrong things are true. In this case, when astronomers say "baryons" they mean "baryonic matter" i.e. atoms, molecules, ions, etc. which includes the electrons. Of course, in baryonic matter the electrons make up something like 0.02% of the mass, so it's hardly worth quibbling about.

    2. Re:huh? by Captain+Nitpick · · Score: 4, Interesting

      In astronomy, "baryons" can also include "leptons", simply because leptons are included in the mass that one measures using a galaxy rotation curve.

      Nope. Baryons are the heavy particles made up of three quarks. Leptons are light particles that are themselves fundamental particles. In between are mesons, made of a quark and antiquark.

      You've got to remember that the terminology astronomers use is a bit...different. This is much like how they call anything heavier than helium a "metal".

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      But then again, I could be wrong.
  2. Why is the probe at the L2 point? by Ponderoid · · Score: 3, Interesting

    Can anyone tell me what's so special about the Sun-Earth L2 point that made it attractive to put the probe there? I couldn't find any reference on that site about why that spot was chosen.

    At first I thought that it might need permanent shade from the sun, but I checked and found that the Earth's umbra doesn't extend that far out.

    Unlike L4 or L5, the L2 position is a meta-stable point, requiring frequent correction to remain in place. There had to be a very good reason to choose it. The site has quite a bit of info about what exactly that spot is (nothing I didn't know already) and how the probe got there, but not a word why.