Time Flies

10/16/05 – 10/22/05

By C. Zaitz

The Romans had a saying, “Tempus Fugit.” Even the ancients had the feeling of time flying. On the other hand, October has 31 days, and February only 28; so why does February feel twice as long as October? “Tempus Crawlus” in February, apparently. Did Einstein have a theory on that? “Winter Blues Relativity?” On a day to day basis, we tend to think of time as a chunk of something, be it small or big. “Wait a second.” “Give me a minute.” “I’ll be there in three shakes of a lamb’s tail.”

Time is an arbitrary measurement. Do you know how we measure a second? It’s kind of like watching a lamb’s tail shaking. Here’s a home recipe for an atomic clock: take a cesium 133 atom, heat it up, pass it through a magnetic field, then a microwave field, then let it get hit with just the right amount of energy so it transitions into another state and “rings” 9,192,631,770 times a second. Every time it oscillates 9,192,631,770 times, another second has gone by. I’ve written that number twice because it fascinates me. That’s nine billion, one hundred ninety two million, etc. It seems so arbitrary, like the speed of light. I met a man once who had memorized that number. He’s actually an astronomer/author who’s books you can find in the chain book stores. And he can spout, at any given cocktail party, the number of oscillations a cesium 133 atom needs before it transitions. I don’t know why he can, but I do remember being impressed. OK- which is nerdier, memorizing that number, or being impressed at someone who memorized that number?

Cesium atom clocks tell time accurately. They are precise to about a billionth of a second each day. That means that our current atomic clocks will stay accurate for about six million years. Time keeping hasn’t always been that accurate. We’ve used dripping water, sand, weights on strings, quartz, and now cesium 133 atoms. But some say the cesium clock isn’t good enough. They talk about a mercury ion clock whose accuracy is astounding. If such a clock had started “ticking” at the Big Bang, by now, some 13 billion years later, it would be about two seconds off. I guess it would be great if you really didn’t want to be late. Ever. I’m not sure how to strap such a contraption to your wrist, however.

So time flies, whether we mark it accurately or not. But the easiest way to stop time from flying is to look up into the night sky. No matter what you see, you will always be looking back in time. When the light from Mars finally reaches your eyes, it will have traveled for about four minutes. So you are seeing Mars as it looked four minutes ago. That’s not so impressive until you look at a star like Polaris, which lies some 430 light years away. The North Star’s light has been traveling since the year 1575. That’s some old light!

When night falls and the little hand is on 9 and the big hand is on 6, you can go outside and look for Mars. Saturn rises after 2am, and will glow brightly in the pre-dawn eastern sky.

Until next week, my friends, enjoy the view!