Surface of last scattering

Cosmology (Winter, 2009)

March 2, 2009

In this lecture Prof Susskind introduces the manifestation of the Universe at different distances, times and places. He discusses how the early universe was hot, but why the background microwave radiation doesn’t appear “hot like the sun” due to red shifting.  Prof Susskind discusses how hot the universe was, and up to what point the Universe was opaque.  Prof Susskind discusses that at extremely hot point, the hydrogen atoms are ionized.  He discusses the idea of X-ray photons.  Prof Susskind introduces the fact that most of the particles out there are photons, but in the early universe they were x-ray photons, and thus were far more energetic.  We study the nature of the early universe as mostly ionized gas, and opaque.  Prof Susskind discusses how the surface of last scattering is the point (looking back in time) when the universe becomes opaque.  He derives early universe constituency based on known atomic physics.  Prof Susskind discusses Neutron decay, nuclear binding energy and neutron stars.