Funny numbers

I was asking stupid questions over at Cosmic Variance today, trying to learn a thing or two about dark matter, when I had to look up the ratio between an astronomical unit and a light year in order to prevent myself from seeming even stupider than I usually do. The number, according to the internet, is 63,240. This struck me as familiar, somehow. I’d seen something very similar in my distant American past, so I did a double check, just to make sure. And yes indeed, it was very similar to the number of inches in a mile- 63,360. They differ by less than 0.2%

If you’re a numerology-worshipping monarchist, then this is proof positive that the British monarchy is endowed with the divine right of Kings, as Elizabeth I put her official stamp on the English mile and inch specifically to make sure they had astronomically meaningful ratios.

For the rest of us, it is a good excuse to teach Americans the relative distances for planetary and astronomical objects.

For example, since a scale of one inch=1au means that 1 mile is pretty damn close to 1 light year, you can construct the galaxy like so:

Go to the Lincoln Memorial, in Washington DC. Put the sun on the tip your nose.
Mercury is across your nostril.
Purse your lips, and Earth is in the corner of your mouth.
Smile, and Mars is.
Jupiter in in your voice box.
Saturn is in your heart.
Neptune is in your pants.
The Voyager 1 spacecraft is about 9 feet away.
The farthest known dwarf planet, Sedna, circles around your feet and out to the top of the steps.
The Oort cloud starts at your knees, and stretches out to the Washington Monument.
The closest star, Alpha Centauri, is in the parking lot behind RFK stadium
The brightest star, Sirius, is on the college park campus of UMD, just over the NE border of the district.
The brightest northern hemisphere star, Arcturus, is in Baltimore.
The bright red star in Orion, Betelguese, is in Boston.
The bright blue star in Orion, Rigel, is in Memphis.
The bright star in Cygnus, Deneb, is in southwest Ireland.
The Milky Way galaxy is 12 times the diameter of Earth, or a bit larger than Jupiter
The Small Magellanic Cloud is as far away as the moon.
The Andromeda galaxy is 10 times as far.

And the best part? Metric Nazis can’t do this trick.