Time Keeps on Tickin'...Into the Future

This article at Nautilus suggests that a quarter of Americans actually believe the Sun revolves around the Earth instead of the way things actually are. Writer Matthew Sedacca doesn't offer any evidence to back that up or links to a survey that bear him out, but I feel pretty sure that whether or not it's a quarter of us or fewer, there are plenty of people who think that way. How that would stack up to the rest of the world -- in places where they think cameras capture their souls, for example -- is also something Sedacca leaves out.

In any event, he notes that recently we marked what software entrepreneur David Schneider calls "Galactic Tick Day" back on Sept. 29. Schneider says a "tick" marks our solar system's traveling one "centi-arcsecond" in its journey around the Milky Way's central black hole.

A "centi-arcsecond" is a measurement of distance around the circumference of a circle. We have designated circles as having 360 degrees, with 180 being halfway around, 90 being a quarter of the way around, and so on. Degrees are divided into minutes and seconds for fields that use very very small angles, including astronomy. An arcminute is a sixtieth of a degree and an arcsecond a sixtieth of that, or 1/3600 of a degree. The tick suggested by Schneider is 1/100 of one of those seconds, which sounds like a very small distance.

It would be, if your circle didn't take 225 million years at 514,000 miles per hour. It takes us just under 634 days between ticks, Scheider estimates, which means we have gone 7.8 billion miles since the last tick. Schneider arbitrarily picked as the starting point the date of the first patented telescope (October 2, 1608), and we have traveled 235 ticks or about 180 trillion miles since then.

Schneider said he conceived of the concept of "galactic ticks" while on a hike as a way of changing perspective and helping people understand something of the vastness of the universe. I think he's definitely onto something, although I confess someone in my line of work has other sources to prompt such musings.