[meteorite-list] Frequent Fireballs

[Ron Baalke]

http://spaceweather.com/

Frequent Fireballs
spaceweathter.com
December 3, 2006

HOW MANY FIREBALLS?  Have you ever stepped outside after dinner 
to walk the dog--just in time to see a bright fireball streak 
across the sky? It makes you wonder, how often does that happen?

Pretty often, according to astronomer Bill Cooke of the Marshall 
Space Flight Center. Using a computer model of Earth's meteoroid 
environment, he made this plot showing the global number of 
fireballs per day vs. the brightness of the fireball:

[Plot]

According to his calculations, fireballs as bright as Venus 
appear somewhere on Earth more than 100 times daily. Fireballs 
as bright as a quarter Moon occur once every ten days, 
approximately, and fireballs as bright as a full Moon once 
every five months.

The vast majority are never noticed. About 70% of all fireballs 
streak over uninhabited ocean. Half appear during the day, 
invisible in sunny skies. Many are missed, however, simply 
because no one bothers to look up. So grab a leash and a dog 
(optional), and head outside. The chance of a fireball is 
better than you think.