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348

cosmic microwave background

OLogy Series
astronomy
card
348

cosmic microwave background

OLogy Series
astronomy

In 1964, two astronomers at Bell Labs in New Jersey started testing a horn-shaped radio antenna. They encountered a "noise" they couldn't explain, a low-level energy, coming from all directions in the sky. The energy turned out to be the oldest light ever seen -- light from just after the big bang, 13.8 billion years ago. This glow came to be called the cosmic microwave background.

In 1965, two astronomers detected unusual background "noise" while testing a horn-shaped radio telescope. They thought it was caused by:

interference from television static

pigeon poop on the telescope

torn wiring

Are you right?

Correct!

The radio telescope was able to pick up the mysterious radiation because it could detect longer wavelengths.

The cosmic microwave background shows the universe as it appeared:

at the moment of the Big Bang

a few hundred thousand years after the Big Bang

when the solar system's planets formed

Are you right?

Correct!

The Big Bang itself emitted no light. The universe then was so dense that light could not escape; it was opaque. After expanding for about 380,000 years, the universe became transparent, meaning that light could slip free. This first light is the cosmic microwave background.

We can see light from the cosmic microwave background with our naked eye.

Fact
or
Fiction
?

Fiction

We cannot see the cosmic microwave background. This light reaches us as microwaves, which have longer wavelengths than visible light.

Definition: the microwave energy observed from all directions in the sky, interpreted as the afterglow from the Big Bang
Formation: 380,000 years after the Big Bang
Temperature: 2.7 degrees above absolute zero
Discovered: In 1965, by Arno Penzias and Robert Wilson of New Jersey's Bell Labs