21
Cosmic
Microwave Background Observations
•First detected by Wilson and Penzias in
1960’s
–Serendipitous detection – thought is was noise in their radio telescope but couldn’t find
cause. Only later heard of theoretical predictions
•Best spectrum observed by COBE satellite
–Red curve is theoretical prediction
–43 Observed data points plotted there
error bars so small they are covered by curve.
error bars so small they are covered by curve.
–it is covered by curve.
•Isotropy also measured by COBE
–T varies by less than 0.01 K across sky
–Small “dipole” anisotropy seen
•Blue = 2.721 Red = 2.729
•Caused by motion of Milky Way falling towards the Virgo supercluster.
