Expert: Philip Stahl - 8/18/2009

Question
Hello Sir,
I am Steffi Michael,
Cosmic microwave background radiation{CMB}  is a topic important & in relation with the big bang. Can I know what it is in detail.
How much energy is released in a supernova approximately.
Waiting for answer....

Answer
Hello,

First let's deal with the last part, concerning the energy associated with supernovae. This was already addressed (two years ago, in previous questions answered) and you can find the answer here:

http://en.allexperts.com/q/Astronomy-1360/Supernovas.htm

As to the cosmic microwave background radiation, in 1965, two Bell Laboratory astronomers - Arno Penzas and Robert Wilson - detected an unexpected background "buzz" in every direction in which they pointed their radio telescope. Analysis of many radio records from different directions disclosed the source was consistent with the background relic (remnant) radiation, left over from the Big Bang. This had already been predicted in the 1940s by George Gamow and others. Most amazingly, there was the confirmation of the radiation being isotropic  - or the same in every direction.

Over the decades following the initial discovery many rocket, balloon and ground based measurements confirmed that the spectrum of this background relic radiation was "Planckian" meaning it had a black-body radiation profile. (You can google 'black body radiation')  Later, in 1989, the Cosmic Background Explorer (COBE) satellite confirmed not only that the radiation was Planckian, but that it displayed a *perfect Planck spectrum* with a black body temperature of T = 2.736 K (Kelvin).

Two paragraphs above, I stated the radiation was "isotropic" but in the interest of technical accuracy I ought to modify that somewhat ...that it is *nearly* isotropic, as detailed analyses uncovered. In fact, there are two notable deviations: 1) a dipole deviation, embodying cos(theta) term that can be traced to the Earth's motion relative to the background relic radiation, and 2) temperature-density deviations that were detected by the COBE satellite on the order of 10^-6 K.

What the latter findings mean is that the universe was not perfectly "isotropic" at the time or epoch that the radiation was generated.

Hope this info is useful. You can also probably do some specific and directed googling to learn more.