A Moment of Science

Better Than Barney

What is better than Barney? Really? Learn about the Big Bang on this Moment of Science.

We’ve heard it a hundred times before. There’s never anything to watch on television. Fifty channels and not one worth sitting down to. Well, PBS is nice. But you get the idea.

If you feel bored by TV, why not try a little experiment? All you have to do is turn to a station where nothing is currently being broadcast. What do you see?… That blank screen isn’t really blank. Rather it’s full of random-seeming flashes of light, sometimes called “snow.” Now, what if we told you that you have just discovered evidence of the Big Bang?

It’s true. Around three percent of the little sparkles of light you see on an unused channel are caused by photons left over from the Big Bang, the explosion that started off our entire universe. Here’s how it works.

For about 300,000 years after the Bang, the universe was so dense that photons couldn’t go anywhere without bumping into electrons and being annihilated. At that 300,000 year mark, however, things cooled off enough to allow atoms to form. That gave electrons something to do instead of always intercepting photons. The photons were set free, to cruise endlessly through space, right up to the present day — about 15 billion years later.

These photons fill all of space, trillions passing through your body every second. They are so weak by this point, though, that you can’t see them or sense them. Unless you open up an antenna to a similar wavelength and listen. Your television set is just the machine to do this.

So take another look at that fuzz. It’s brought to you by the origin of the cosmos.

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