IO's diameter ~3600km Avg distance to earth ~628m km Apparent diameter is ~5 microradians or ~1 arcsecond Similar to imaging a marble 5mm in diameter from 1k

IO's diameter ~3600km Avg distance to earth ~628m km Apparent diameter is ~5 microradians or ~1 arcsecond Similar to imaging a marble 5mm in diameter from 1km away. Betelgeuse is ~1.2 billion km in diameter (for now, lol) It's 642 light years away. It's apparent diameter is .2 microradians, or approximately a red blood cell from 35m away. Space is big. Things are small.