Thursday, February 18, 2010

Play WMAP's "Build A Universe" Game.

*UPDATE*: The game doesn't seem to be on this site working correctly.  Go to the WMAP link to play it. It will make more sense.  Sorry about that. (It really is pretty cool!)

How do scientists use Cosmic Microwave Background (CMB) data to figure out how much dark energy, dark matter and regular matter there is? How do they calculate other fundamental quantities such as Hubble's constant?

One way is to examine a real gem that can be extracted from the CMB: The power spectrum. (See above image.) The power spectrum is a 2-point correlation function which means it determines how well different points in the sky relate to each other. (See link for explanation of what this is.)

It turns out, the shape of the power spectrum is highly sensitive to the values of many physical parameters such as percentage of dark matter, dark energy, the value of the spectral index, etc... To demonstrate how much this is the case, I have attached WMAP's "WMAP's CMB Analyzer".  It is a fun little game that at the same time is very educational.

Hint, best fit values from CMB are approximately:
Atoms: 4%
Cold Dark Matter: 22%
Dark Energy: 74%
Hubble's Constant: 73
Reionization Redshift: 11 z
Spectral Index: 0.96


  1. So if I can create the Universe, does that mean I can finally make some Apple Pie from scratch? =:)

  2. Stan.

    Yes. This is the only way to really make one from scratch. (Nice reference to Carl Sagan .)

  3. i created a universe in my latrine...
    full of life...
    black holes...
    dark matter...dark energy...and a strange...yellow liguid...


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