DSD

Phil Plait over at Bad Astron­omy has a great post fea­tur­ing some awe­some facts about everyone’s favorite star. Alright, you prob­a­bly know some of them. But there’s some good stuff in there. A cou­ple of my favorites:

Usu­ally, dam­age to the eyes from look­ing at the Sun hap­pens dur­ing a total solar eclipse. The eclipse itself doesn’t hurt you — after all, the point of the eclipse is that the Sun is cov­ered by the Moon! — but the dam­age hap­pens in the moments right after the eclipse. While the Sun is blocked, your pupil dilates to let in more light, so when the first sliver of the bril­liant Sun reap­pears your eye is flooded with light. This can cause dam­age to your retina called solar retinopa­thy. It’s actu­ally not heat dam­age, but pho­to­chem­i­cal; the flood of UV light actu­ally alters the chem­istry of your cells, dam­ag­ing them.

In gen­eral, the dam­age is minor and can heal well, though there can be some per­ma­nent though rel­a­tively minor effects (in other words, you still shouldn’t stare at the Sun). Usu­ally the dam­age is worse in chil­dren because their lenses let in more blue light (the lens yel­lows with age, act­ing as a nat­ural fil­ter for UV light). […]

Inci­den­tally, using sun­glasses to look at the Sun can actu­ally make things worse, since they block vis­i­ble light and your pupil dilates to com­pen­sate. If you want to observe the Sun — and I rec­om­mend it, because it’s fas­ci­nat­ing and utterly beau­ti­ful — then read Mr Eclipse’s guide to safe solar view­ing. It’s a site for sore eyes.

The Sun is not an aver­age star […] As with most things in nature, the num­ber of objects depends on the size. There are very few high mass stars, more inter­me­di­ate mass stars, and gazil­lions of low mass stars. Roughly 10% of all stars by num­ber in the Milky Way Galaxy are like the Sun, which means that very few are more mas­sive. Even being con­ser­v­a­tive, I’d say that the Sun is more mas­sive than 80% of the stars in the Galaxy.