Geologic time, astronomic speed

FullSizeRenderThis past weekend, my band played a festival near Nordegg, Alberta. During our drive back to Calgary on Sunday, we stopped off at the Num-Ti-Jah Lodge on Bow Lake. While I was looking across the water at the Crowfoot Glacier and some mountain I’ll never know the name of, I casually mentioned to one of the guys how cool it was that, though every mountain around us was in constant motion, the geologic timescale of it made us see all that sedimentary rock as frozen in time.

Seriously, that’s the kind of thing that occupies my head and makes me boring at parties. The strata in a mountain’s rocky face will kick my inner geologist awake every time. And then I get carried away with the immenseness of the whole thing. It’s unfailing—and maybe just a touch humbling.

Okay, now stare into the night sky. Things look pretty static, right? Well, there are some pretty colossal mechanics in motion up there, too. And here’s the rub: although every celestial body you could think of is rushing headlong through spacetime at ridiculous speed, the enormous distances involved make everything beyond our own solar system look just as frozen in time as that mountain across the lake from me did on Sunday. The best example of this is Andromeda, the biggest and most massive of the Local Group of galaxies, which includes ours. Sounds obvious because it is.

Andromeda is barrelling towards us at about 110 kilometres per second, and because its sideways velocity is extremely small, we’re essentially on our way to a head-on collision. Sounds deadly, right? Not so fast: there are wildcards involved, and the biggest one is the scale. The stretch from one star to another is merely gigantic, while the distances between galaxies are truly immense (For example, the star closest to ours is Proxima Centauri, which is four and a quarter light-years away. Andromeda? 2.5 million light-years. Yikes, eh?). The upshot is that there’s little chance of any stars hitting each other as the galaxies crash. Instead, the damage will manifest by morphing the two gorgeously spiralled star cities into a single large, boring elliptical cluster. Okay, our solar system might get ejected from the whole works because gravity works in mysterious ways, but that’s not the important point. The big thing here is that the gap that the Milky Way and Andromeda have to cross is so brain-blazingly large that it’s going to take about 4 billion years for them to meet.

Simply everything out there in the universe works in æons and light-years. For a species with an average lifespan of under a century, of course it looks like nothing’s moving. We live in a timescale sandwich between the geologic, where the motion is so slow that you just don’t notice it, and the astronomical, where the speed is extreme but the distance makes it almost irrelevant.

If this makes you feel small, pull up a chair.

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