Texas Fireball Event - December 7th, 2012 @ 6:30 CST
For those not familiar with meteors and fireballs, a fireball is a meteor that is larger than normal. Most meteors are only the size of small pebbles. A meteor the size of a softball can produce light equivalent to the full moon for a short instant. The reason for this is the extreme velocity at which these objects strike the atmosphere. Even the slowest meteors are still traveling at 10 miles per SECOND, which is much faster than a speeding bullet. Fireballs occur every day over all parts of the Earth. It is rare though for an individual to see more than one or two per lifetime as they also occur during the day, on a cloudy night, or over a remote area where no one sees it. Observing during one of the major annual meteor showers can increase your chance of seeing another one of these bright meteors.
Meteors often appear much closer than they really are. I receive countless reports that the object landed just over the hill when in fact it was several hundred miles away and was witnessed over several states. It is your perspective that makes meteors appear to strike the horizon when in fact they are still high in the atmosphere. This is much like a jetliner seen low in your sky. It appears low to you but for someone located many miles away in that direction, the jetliner is passing high overhead. Meteors become visible at approximately 50 miles above the Earth's surface. Friction slows these objects down until they fall below the velocity necessary to produce light. At this point they still lie at least 5 miles high in the sky. They are invisible below this altitude and cannot be seen as they basically free falling to the ground at 200mph. Very few meteors actually reach the ground as 99.99% completely disintegrate while still 10-20 miles up in the atmosphere.
definite assertions put out there by Robert Lunsford.
"Fireballs occur every day over all parts of the Earth."
Sure, they do NOW, like in the last three or four years.
"Observing during one of the major annual meteor showers can increase your chance of seeing another one of these bright meteors."
I think that's very unlikely. I've been keeping an eye on NASA and others' reports of fireball events this year and it seems that most of the blazing bolides had trajectories and points of origin that did NOT fit with any known meteor shower.
"They are invisible below this altitude [5 miles] and cannot be seen as they basically free falling to the ground at 200mph."
Basically? Well, it's a wrap then!
Seriously, so little is known about this subject that the opinion of anyone who claims to know exactly 'what, why, how and where' regarding fireballs should be treated with caution.
"Very few meteors actually reach the ground as 99.99% completely disintegrate while still 10-20 miles up in the atmosphere."
99.99%, is that a fact?
These are just from 2012:
Daytime fireballs spark ground fires in Okanagan Valley, British Columbia [Link]
Reign of Fire: Meteorites, Wildfires, Planetary Chaos and the Sixth Extinction [Link]
Fireball starts wildfire in Reno, Nevada [Link]
Meteorite starts fire in Itatiba, Brazil following separate Fireball incident in neighbouring Campinas days earlier [Link]