[music playing] In 2009 when television converted to digital broadcast the beginning of the universe went off the air.

A small amount of the crackling static on an old TV was radiation from the universe's youngest days.

In the first few seconds after the Big Bang, the universe was a sea of free electrons and atomic nuclei so unbelievably hot and dense that not even photons could escape that opaque cosmic pinball machine.

Eventually, a few 100,000 years later, things spread out and got cold enough that neutral atoms could form.

And the first light finally went streaming out in every direction.

And for a while, like a few hundred million years while, those first photons were the only light in the universe until early atoms condensed to form the first stars.

Today light from stars is the only glow we can see in the night sky, but in every direction hiding in the background is the first light, the earliest picture of the universe that we can see, the cosmic microwave background.

Now it gets that name because along their 13.7 billion year journey those first photons have been stretched and cooled by the expanding universe drawn from visible wavelengths down to microwaves and radio waves.

Even though you can't see it with the naked eye, you can still catch it.

Every time you tune your FM dial between stations you turn your radio into an accidental telescope, just not a very good one.

But that's fitting since the discovery of the cosmic microwave background itself was a radio accident.

In 1964 Arno Penzias and Bob Wilson at Bell Labs were trying to use a giant radio dish to bounce transcontinental radio communications off big shiny balloons placed in orbit, Project Echo.

I guess before cell phones we were willing to try anything.

The Bell Labs dish in New Jersey had to be incredibly sensitive to pick up the weak signals, which also meant it picked up a lot of natural interference.

But even after correcting for all that, Wilson and Penzias couldn't get rid of one mysterious bit of static.

[static] No matter where in the sky they pointed the antenna, day or night, the static was there.

It didn't come from our sun or anywhere else in our galaxy.

They even cleaned the pigeon poop off the dish, and still the noise continued.

When they heard that other scientists formulating the foundations and the Big Bang Theory were going in search of microwaves precisely in the range they heard their mysterious static, they suddenly realized what they had found, the echo of the Big Bang.

The splotches in the cosmic microwave background are tiny fluctuations in density, just one part in 100,000.

That gave the universe just enough gravitational lumpiness to let little blips condense into bigger and bigger blips, eventually seeding the stars, and galaxies, and galaxy clusters that make up our everything.

This early picture has helped scientists explain why the universe looks the way it does today.

So whether you're basking in the young light of the noonday sun or standing under the ancient light of the stars at night, remember you're always bathed in the forever light of the cosmic afterglow.

Stay curious.