What is the cosmic microwave background radiation?
A) An almost-uniform background radiation from distant,unresolved,overlapping galaxies
B) Radiation left over from the Big Bang,after the universe expanded and cooled
C) A uniform background of radiation from electrons spiraling in weak intergalactic magnetic fields
D) Radiation from a very tenuous,ionized gas that fills the universe equally in all directions

Question

Quizplus · Accepted Answer

The Cosmic Microwave Background Radiation (CMBR) is radiation left over from the Big Bang, after the universe expanded and cooled. It is believed to be the oldest light in the universe and is almost uniform in all directions at a temperature of approximately 2.73 Kelvin. The CMBR is considered one of the most important pieces of evidence for the Big Bang theory.

What Is the Cosmic Microwave Background Radiation