Science trivia of the day

[andygates]

Get above the atmosphere, where you're exposed to cosmic particles.  Close your eyes.  Those blue flashes you see are Cherenkov radiation - the photonic equivalent of a sonic boom - caused by cosmic particles moving through the liquid in your eyeballs at a speed greater than the speed of light in your eyeball. 

Comments

[thudthwacker.livejournal.com]

I believe -- and may be wrong, because me, I'm no authority -- that Cherenkov radiation will produce a visible blue glow even if the particles in question aren't exceeding the speed of light in your eyeballs. Which is why, for example, you can photograph it.

In any case, no baby, I wouldn't want to see it. I'm pretty sure that there being Cherenkov in the visible part of the spectrum and near enough to you that you can see it guarantees that you're being hit by enough ionizing radiation to kill you within the fortnight.

[despaer.livejournal.com]

The particles won't exceed the speed of light in a vacuum ('cos nothing can) but they can exceed the speed of light in the medium through which they are travelling

[thudthwacker.livejournal.com]

Jah, sure, youbetcha, I knew that.

[andygates.livejournal.com]

And the speed of light in an eyeball is about .75c

[andygates.livejournal.com]

Oh yes, it certainly can be photographed. It was just the phenomenon of having it occur in your eyeballs - because outside the magnetosphere the cosmic ray particles can get to you - that tickled.

Ionizing radiation's bad, hm'kay ;)