Yesterday’s APOD

By | March 20, 2009

Yesterday’s Astronomy Picture of the Day was particularly awesome. I mean, APOD is usually awesome every day, but yesterday’s was particularly awesome, being a photo of Saturn, showing four of its moons in the foreground, all large enough that you could get some idea of their relative size and, in the case of Titan, colour. Cool, huh?

I find that astronomical pics are often hard to put into perspective. Supernova remnants look cool and majestic, but looking at them, it’s almost impossible to appreciate how truly vast they are, and how much energy was released in their creation. To describe astronomical objects, we have to use either units or numbers that are on a completely different level to what we’re built to comprehend. For example, a light year is about 10E12 kilometres, and a solar mass is 2E30kg, a number so large that there’s no commonly used word to describe it (though, apparently, nonillion is the correct term).

This isn’t some great insight, it’s just something that leaves me in awe of the universe and makes life’s petty concerns seem so, well, petty. So, I like anything that helps me appreciate that scale, and this photo, by showing Saturn’s moons in context, does just that. Other examples include looking out the plane window over Wellington to see the Marlborough Sounds, Golden Bay, and the Southern Alps laid out in panorama, and that photo of Phoenix drifting in to land on the surface of Mars from May last year. Some people use God and religion to give themselves perspective. Space, among other things, does that for me.