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What is cosmic microwave background radiation?
CosmologyBackground Radiation
Quick Answer
Cosmic microwave background radiation is the faint afterglow of the early Universe, visible in every direction. It comes from about 380,000 years after the Big Bang.
The Full Story
The cosmic microwave background, or CMB, is radiation left over from when the early Universe cooled enough for atoms to form and light to travel freely. It was discovered accidentally in 1965 by Arno Penzias and Robert Wilson. Today it is observed as a nearly uniform microwave glow at about 2.7 kelvin, with tiny temperature variations that reveal the seeds of later galaxies. The CMB is one of the most important pieces of evidence for the Big Bang model.
Key Facts
1.The CMB was discovered in 1965
2.Its average temperature is about 2.7 kelvin
3.It dates to roughly 380,000 years after the Big Bang
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Suggested video title for this topic:
"The oldest light we can still detect, coming from all around us"