Saturn, 75 minutes old

The planet Saturn is at its closest to the Earth, at some 1,350 million kilometers. A spectacular image has been shot at Aguadilla, Puerto Rico [by Efraín Morales Rivera and provided by the Sociedad de Astronomía del Caribe]: here.

This reminds me how beautiful and multi-facet is the Web. One day we see LOLcats and the next, Saturn. However, what came to mind immediately after noting its distance from us is: How long does it take for the light from Saturn to reach us?

Easy: Divide 1,350 million km by the speed of light (approximately 300,000 km per second) and the answer is there: 4,500 seconds, that is 75 minutes, or 1 hour and a quarter.

1 hour and 15 minutes it takes, traveling that huge distance. This means that the image we see is 75 minutes old when we watch it, at least. The actual planet might have vanished in that lapse, or exploded (very, very unlikely for the time being). But this is just a reminder that space gazing is time-travel. We always see the Universe as it was in our past, a few seconds, minutes (8 for the sun), or years away. We may feel this is a terrible limitation, being unable to see the Universe as it is now (on the Earth). But there’s also another side to the same coin. We are thus able to see the Universe as it was one million years ago, when the Earth was young, and learn accordingly. Anyway, this feels to me like a very humbling sense, and a connection magic beyond any scripture.


Originally published at Skate of the web.