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Simple but Challenging: The Universe According to Planck

• xk_id 14y ago
  Wow. Looks like time for a revolution in physics.
• cristianpascu 14y ago
  Could someone, please, clue me on something that has been on my mind for a while now: The thermal radiation coming from distant stars has been red-shifted by the Universe expansion, together with the light in the visible spectrum. I suppose. Is it now in the same spectral area as the background radiation? Or is it the same thing? Also, if we see the stars, do we also see the thermal radiation coming from them?
  • shardling 14y ago
    Starlight (and sunlight) chiefly is thermal radiation. The CMB is something distinct, originating from before there were any stars at all! Re:contamination, luckily stars in general are fairly sparsely distributed, so we can simply remove those areas. Apparently the plane of our own galaxy does have to be mostly cut out, though. http://en.wikipedia.org/wiki/Cosmic_microwave_background_radiation#Data_reduction_and_analysis http://en.wikipedia.org/wiki/Cosmic_microwave_background_rad...
    • XaspR8d 14y ago
      > Starlight (and sunlight) chiefly is thermal radiation. I just wanted to clarify for others that while we are used to learning that stellar radiation "originates" from nuclear fusion, most of the emission from fusion is absorbed by the outer layers of the star and then re-emitted. Hence why it is all thermal, and why starlight replicates blackbody radiation so well. Just something I had been confused about for a while. Feel free to correct me if I am still confused. ;)