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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."

12 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.

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    1. Re:huh? by Peter+T+Ermit · · Score: 2, Interesting

      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.

    2. 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.

    3. 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".

      --
      But then again, I could be wrong.
  2. Re:courtesy of Wikipedia by Scud_the_disposable_ · · Score: 2, Interesting
    from the definition of dark energy:

    This energy would act like a vacuum pressure, pushing things apart.

    now I ask you... what is vacuum pressure, and how does it push things apart? I thought vacuums sucked things in...

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    tcpa SUX!!!!
  3. 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.

  4. Time is continuous, isn't it? by MlBruehlly · · Score: 2, Interesting

    Since time has been proven to continue into infinity, why do we state that the universe 'started' 13.7 billion years ago? What was happening 13.8 billion years ago in the space we currently occupy? Surely the Big Bang was a result of some other cosmic event, since time could stretch infinitely into the past as well as the future. The universe couldn't have been born without being first conceived...

  5. Re:courtesy of Wikipedia by Anonymous Coward · · Score: 2, Interesting

    Stephen Hawkin, in his book "A Brief History of Time", says (when talking about Black Holes) that there can't be "empty space" because of the Uncertainty Principle, and thus what is known as "empty space" is really particles and antiparticles creating and destroying each other all the time.

    He then goes to say that for each pair of particle-antiparticle, one can be sucked into the Black Hole while the other, failing to be destroyed by it's counterpart, escapes and allows us to detect the black hole.

    He then goes into saying that because an antiparticle would behave exactly the oposite than the particle, what would appear to be a pair being created and destroyed, would really be a particle going forward and backwards in time in a "circular " manner... and we would see it as a particle - antiparticle pair.

    But I'm not and physicist, so I wouldn't know better than what Stephen Hawking wrote... anyone care to elaborate?

    Cheers.
    Me

  6. No, but excellent question by efuseekay · · Score: 2, Interesting


    No, unless your coffee has been artificially cooled below the temperature of the universe.

    No naturally occuring cups of coffee in the universe will need any cooling from the CMB :).

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  7. Perhaps you or someone else could explain... by Anonymous Coward · · Score: 1, Interesting

    Doesn't the fact that 95% of the universe is "dark" suggest we have a very poor understanding of what is actually going on?

    I mean, when we only know what 5% of the universe is, doesn't that suggest our current understanding of things, physically speaking, is pretty bad?

    I don't mean to sound like a troll or anything, but really: if this were any other field of science, it would sound like current theory were woefully inadequate. I mean, to not be able to explain 95% of your subject matter...

    What am I missing?

  8. Astronomy Picture of the Day by msheppard · · Score: 2, Interesting

    The map (really big version too) is today's Astronomy Picture of the Day. Along with another good description of the findings with the typical excellent APOD links.

    Go Apod!
    M@

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    Krispy Cream is people
  9. Dark Energy Sucks. by Ardias · · Score: 2, Interesting

    Dark Energy Sucks because it exerts a negative pressure on the universe. (There's a neat article about positive and negative pressure in the most recent Scientific American - including stuff about dark energy and the cosmos.)

    Anything with a negative pressure sucks.
    Anything with a positive pressure blows.