The American Meteor Society has so far received approximately 50 reports of a bright fireball over much of the southwestern states of the USA,Â from Colorado to California.Â Most of the reports have come from Arizona and New Mexico. This event occurred at 8:15pm MST Saturday evening December 31st.
NASA scientists were able to capture this event on video cameras located in Las Cruces and Mayhill, New Mexico and calculate that the object, only two inches in diameter, entered the atmosphere between Las Cruces and Albuquerque, New Mexico, and traveled a short distance to the northwest toward the Arizona border. The calculated magnitude was -8, which is slightly inferior to the light produced by a half moon. The entry velocity was also calculated to be 16.2 miles per second and the ending altitude was 51 miles. This object was a random fireball as it did not belong to any known meteor shower.Â Many thanks to Bill Cooke of NASA for providing these figures so soon after the event.
Links to videos of this event are available at:
http://www.billcooke.org/events/NM_20120101/ev_20120101_031540A_06A.mov andhttp://www.heliotown.com/FBS20120101_0315utBW_Ashcraft.mp4 andhttp://www.heliotown.com/FBS20120101_0315utHE_Ashcraft.mp4 Also thanks to Thomas Ashcraft for his two videos obtained near Lamy, New Mexico.
A fireball is a meteor that is larger than normal. Most meteors are only the size of tiny 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 a few per lifetime as they can also occur during the day (when the blinding sun can obscure them), or on a cloudy night, or over the ocean where there is no one to witness them. Observing during one of the major annual meteor showers can increase your chance of seeing another bright meteor.
Fireballs often appear much closer than they really are. The AMS receives countless reports that an 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 60 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 freefalling 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.
In the AMS fireball table, refer to event #1626 for 2011.