Wednesday, August 31, 2011

Ultrarunning...and Sirius (the star, not the radio)

Tuesday the bride and I walked together 2 miles at 5:30 am, then I peeled off to run some additional miles.

When we first started out, coming out of our development the street runs east, and there hanging low in the sky was Sirius, the brightest star in the heavens.  It was twinkling fiercely, so much so that the bride swore it was an airplane, but I knew from prior experience that it was indeed "only" Sirius.

I blogged about Orion and Sirius about a year ago, in a post entitled Running Towards Orion, where I wrote:

Ah, and Sirius! This is the brightest star in the sky. You find it by locating Orion’s belt, then drawing a line from his right side (viewer’s left) “down” some 5 or so belt-widths, where you can’t miss Sirius. It unmistakably twinkles. Per the Crystalinks website,
To the naked eye, it often appears to be flashing with red/white/blue hues when near the horizon.
 Sirius is some 8.6 light years away, meaning that the photons sent our way from that star take over 8 years just to reach us. I cannot imagine the number of photons emitted…figure that Sirius radiates in all directions, not just towards Earth.
 
Earth’s diameter as a percentage of the arc of space into which Sirius radiates is vanishingly minuscule. Then what light reaches earth is spread over the entire Sirius-facing surface of our planet. Some of those very photons enter my eyes (as well as those of all other observers), stimulate my retina, and create the brain image I've been taught to recognize as Sirius. That chain of events is almost too much to fathom.
 

So, by all means get yourself outside, pre-dawn, for some Ultra training.  Get a good view of the eastern sky, and look for Sirius...but don't be surprised if you first think it's an airplane.

 

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