h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

My question was what physical process could cause Zubeneschamali to look green. According to the Bad Astronomy Guy, it could because by rotation.

I don't understand that.

You could ask him. He's no longer at Discovery blogs. Now he's blogging on Slate. http://www.slate.com/blogs/bad_astronomy.html

He's also on Twitter @BadAstronomer.

I found this this morning, when I was looking at images of the blood-red moon with a green-tinged side!

>>Prof. Richard Keen, an atmospheric scientist from the University of Colorado explains: "During a lunar eclipse, most of the light illuminating the Moon passes through the stratosphere, and is reddened by scattering. However, light passing through the upper stratosphere penetrates the ozone layer, which absorbs red light and actually makes the passing light ray bluer!" This can be seen, he says, as a turquoise fringe around the red.<<

Yep. I see this all the time. Astronauts love taking pics of the Earth's limb especially sunrise/set.

Here's an especially dramatic image.

http://apod.nasa.gov/apod/ap951117.html

WOW, that is really an AWESOME pic, Baron.

If I was rotated really fast, I think I might turn green.

Sorry to bring the tone down.

I managed to spot Zubeneschamali last night. At the moment it is easy to find as Saturn is very close to it. It was low down in the sky and dim due to the suburban background light glow, so I couldn't really say what colour it is.

well done!

Running through some older listings at the moment.

There was a controversy about this relating to California state school books back in the 1950s with people like Doc Smith, the science fiction writer and Richard Feynman, the physicist, pressing (successfully) for corrections on a mistaken passage in a proposed text book that asserted that were green stars, on the same principles Gnomon cites, that the Guassian distribution of emitted frequencies around a peak emitted frequency in the green range, in the the spectrum of a black body, will make it appear white to the naked eye, given the mechanics of color vision.

My Green Star entry is now on the Front Page! Another one off the presses.

I saw that.