[deepakg]

This video has comparisons of devastation that would be caused by different sizes (around 7:50 mark) of asteroids: https://www.youtube.com/watch?v=4Wrc4fHSCpw

[hoten]

So a 500m is roughly a couple thousand or ten thousand times more than a Hiroshima nuke?

[jacquesm]

More like 50,000 or so (back of the envelope).