September 6, 2013
Spectacularly Bright Fireball Over Tennessee Confirmed By NASA
[ Watch The Video: Bright Meteor Captured Over Georgia/Tennessee ]
Brett Smith for redOrbit.com - Your Universe Online
Typically, there isn’t much to see in the predawn hours of a Wednesday morning in the Southeast US. However, on August 28, those who happened to be awake and outside at 3:27 a.m. in northern Georgia and Tennessee were treated to the spectacle of a short-lived yet massive fireball that out-shown the moon.
“Recorded by all six NASA cameras in the Southeast, this fireball was one of the brightest observed by the network in 5 years of operations,” wrote Bill Cooke, NASA’s head of the Meteoroid Environment Office at NASA's Marshall Space Flight Center in Huntsville, Ala.
“From Chickamauga, Georgia, the meteor was 20 times brighter than the Full Moon; shadows were cast on the ground as far south as Cartersville.”
According to Cooke, the meteor that caused the fireball was about 2 feet in diameter and weighed around 100 pounds. After entering the Earth’s atmosphere high above the Georgia-Tennessee border near Chattanooga, Tennessee, the meteor streaked northeast at 56,000 miles per hour and began to break apart northeast of Ocoee at a height of about 33 miles above the Earth's surface. A second fragmentation event took place less than half a second later.
“NASA cameras lost track of the various fireball pieces at an altitude of 21 miles, by which time they had slowed to a speed of 19,400 mph,” Cooke wrote. “Sensors on the ground recorded sound waves (“sonic booms”) from this event, and there are indications on Doppler weather radar of a rain of small meteoritic particles falling to the ground east of Cleveland, Tennessee.”
While the Georgia-Tennessee fireball was a unique event for its exceptional brightness, our planet is bombarded with more than 100 tons of material from outer space every day. Most of it consists of grains of dust and bits of asteroids or comets that burn up safely in the atmosphere, occasionally creating shooting stars in the process.
A meteor is considered to be a fireball if it blazes more brightly than Venus in the sky. NASA uses its network of cameras to record and study fireballs in an attempt to understand of where they are coming from. NASA has said that information on even the smallest of meteorites can be useful to spacecraft designers.
“Even the slowest meteors are still traveling at 10 miles per SECOND, which is much faster than a speeding bullet,” according to a statement by the American Meteor Society.
According to “pending” reports on the society’s website, another significant meteor streaked across the night sky Wednesday in the Mid-Atlantic region of Virginia and Pennsylvania. If a large object did enter the atmosphere above those states it would have been picked up by NASA’s All-sky Fireball Network. The network is currently made up of a dozen cameras: six spread across Alabama, Georgia, North Carolina and Tennessee; and two apiece in Ohio, Pennsylvania and New Mexico.
One confirmed object that lit up the March night sky over Washington, DC earlier this year was described by Cooke as a "single meteor event" that was “as bright as the full moon.”
Of course the most famous fireball event to take place this year was the now infamous meteor explosion over Russia's Ural Mountain region that lit up the post-dawn sky and created a window-shattering sonic boom.