Something Cosmic on TV

Astronomically Speaking #1, published in the York University Gazette, October 1999

[NOTE: I am aware that the phenomenon of TV static — and indeed the notion of there being "nothing to watch on TV" — are about twenty years out of date.]

The term has well and truly begun, and mid-terms are upon us. Students are pulling all-nighters, TAs are marking 24-7. Perhaps you’re one of these, or a faculty member in the midst of a bout of insomnia due to Post Sabbatical Stress Disorder.

Regardless: you’re awake, and it’s late.

You could wander outside and gaze up at the night sky, find the soft glow of the Milky Way, spot a few constellations, watch for shooting stars. You could do that ... except it’s raining. No star gazing tonight.

tvstatic.png

Fortunately you can still do some astronomy, right there in the living room. It’s so late, there’s nothing on TV, not even old “Gilligan’s Island” reruns. But turn on the television anyway, and watch the static fuzz, listen to that ‘shhhhh’. Mesmerising, isn’t it? That static is stray electromagnetic waves picked up by your television’s receiver. Some of it is from all the electronics, power lines and so on surrounding us in this modern world. But one-third of the static is coming from beyond our world, from cosmic background radiation (CBR) over fifteen billion years old.

Way back in time, well before Gilligan went on that fateful cruise, before life on Earth, before the Earth even existed — in fact just 700,000 years after the Big Bang itself — atoms first came into being. Before that moment in cosmic history, when the universe was still very hot, space was filled with electrons, protons and neutrons (the particles that make up atoms) and photons (particles of light). It was too hot for these elementary particles to form into atoms, because at high temperatures, they are colliding far too violently to stick together. So all the particles were mixed together into a kind of hot, primordial soup.

But the soup was cooling quickly, and it wasn’t long before it cooled enough to allow atoms to form. Suddenly, where there had been a universe of particle soup, there was a universe full of atoms — Hydrogen atoms mainly, they’re the easiest to make, though there was some Helium too. Even today, billions of years later, our universe is still made up almost completely of Hydrogen and Helium.

All the other elements we find around us, like Oxygen and Carbon and Iron, while they seem pretty important to us, only constitute a tiny fraction of all matter in existence. In fact, essentially everything in the universe other than Hydrogen and Helium was created much later, by nuclear reactions inside stars.

In a very real sense, we are all star dust.

And so, 700,000 years after the Big Bang, space quite abruptly became filled with atoms. As far as the photons were concerned, it was as if the universe suddenly became transparent, like glass. All of the photons, that had moments before been bouncing against all the electrons and protons in the cosmic soup, could now roam the heavens freely. These photons became what we call the Cosmic Background Radiation.

And so, watching the static on your TV screen, a third of those random dots mark the death of a photon — one that has traveled for billions of years, since that moment in time when the stuff of the universe cooled enough for atoms to form. You sit there, bathed in the glow from the television, comforted by these messengers from the distant past.

The rain has stopped now, so you wander our into the cool night air. A little mist plays around the pale streetlights, a sultry jazz phrase wafts down the street from someone’s open window. Overhead, the clouds have parted, and you can see a thousand burning stars — stars that formed long after the CBR photons began their journey. You can’t see those photons with your own eyes, but the cosmos is filled with them. You know this, because you saw them on TV.

And they say there’s nothing worth watching on television.