Time and astronomy go together, from helping early hunters and farmers determine seasons to helping navigators determine longitudinal position in the middle of oceans. On uncharted land also, as with David Thompson.
Clocks have improved over time to the point where even small atomic clocks help GPS systems pinpoint where on our rotating planet we are, what speed we’re travelling at, and trace our highway and backcountry routes. Looking at the sky above, precision is cost-saving; pointing at a tiny far away object at the wrong fraction of a second requires extra searching. Calculating orbits of new objects (and how close some may come by Earth) needs time exact as possible. Timing can get complex, since Earth wobbles in several ways (not as much as doomsayers worry), and GPS signals need adjusting for ionosphere fluctuations.
For some interesting time comparisons, let us suppose we are in Invermere and want to have a scenic drive to Fairmont. (Reference pages give varying numbers so all here are approximate.) Let’s say it takes 900 seconds. If we could go as fast as the Space Station (ISS), we’d get there faster! The ISS, at around 7.7 kilometres per second (kps), would take only three seconds! Handy, say, if one is really hungry for Greek food there.
The speed of the ISS may seem fast, but what about some other speeds of objects in space? Voyager 1 moving out into interstellar space is currently moving at 17 kps. The New Horizons probe on the way to Pluto has a very long way to go from Earth, so it was launched at 16 kps, which translates into less than one and a half seconds from Invermere to Fairmont. The Sun’s distant pull slows it down, but at Pluto it will still sail by at 13.6 kps.
Some other speeds to contemplate. Our own home world orbits the Sun at some 30 kps (which means when you see a first-quarter moon, Earth was at the moon’s spot a bit under four hours ago). The silvery Moon sails along at a mere 1 kps — still a quick trip to Fairmont. Mars orbits at 14 kps, Jupiter at 13 kps. Our sun? It whirls around the galaxy a bit faster at 230 kps. If the numbers are correct, this means about a one-tenth of a second trip to Fairmont. If you want faster, look at Andromeda galaxy, east of square-shaped Pegasus coming up these evenings. That galaxy and ours are approaching each other at some 300 kps. Try calculating time to Fairmont at that speed.
Back to Earth and more leisurely speeds. Thinking of highways, a moose on a clear run can get up to 15 metres per second, a whitetail deer up to 13-plus metres per second. Slower than the ISS? Still interesting to contemplate. Moose and deer have their own schedules, but the ISS starts showing up again in the evenings by mid-October. See www.heavens-above.co.
Brian Fenerty is a semi-retired valley resident and an esteemed member of the Royal Astronomical Society of Canada. Contact him at fenertyb@telus.net.
