[meteorite-list] Fireball Lights Pre-Dawn Sky over Arizona

[Ron Baalke]

http://www.nasa.gov/feature/fireball-lights-pre-dawn-sky-over-arizona

Fireball Lights Pre-Dawn Sky over Arizona
June 2, 2016

For a few seconds early Thursday, night turned into day as an extremely 
bright fireball lit the pre-dawn sky over much of Arizona, blinding all-sky 
meteor cameras as far away as western New Mexico.

Based on numerous eyewitness accounts, a small asteroid estimated at 10 
feet (3 meters) in diameter - with a mass in the tens of tons and a 
kinetic energy of approximately 10 kilotons - entered Earth's atmosphere 
above Arizona just before 4 a.m. local (MST) time. NASA estimates that 
the asteroid was moving at about 40,200 miles per hour (64,700 kilometers 
per hour).

Eyewitness reports placed the object at an altitude of 57 miles above 
the Tonto National Forest east of the town of Payson, moving almost due 
south. It was last seen at an altitude of 22 miles above that same forest.

"There are no reports of any damage or injuries - just a lot of light 
and few sonic booms," said Bill Cooke in NASA's Meteoroid Environment 
Office at the Marshall Space Flight Center in Huntsville, Alabama. "If 
Doppler radar is any indication, there are almost certainly meteorites 
scattered on the ground north of Tucson."

The NASA Meteoroid Environments Office (MEO) monitors the small rock (meteoroid) 
environment near Earth in order to assess the risks posed to spacecraft 
by these bits of tiny space debris. As part of this effort, it operates 
a network of meteor cameras within the U.S. that are capable of detecting 
meteors brighter than the planet Jupiter. Three of these cameras are in 
southern Arizona.

Cooke notes that he and other meteor experts are having difficulty obtaining 
data on the June 2 fireball from meteor camera videos, since many of the 
cameras were almost completely saturated by the bright event.

The event did leave smoke trails that were caught on video: https://www.youtube.com/watch?v=GN--uCY0LUY 
and https://www.youtube.com/watch?v=4sOqPOL1gIM. 

Meteoroid impacts are a continuously occurring natural process.  Every 
day, about 80 to 100 tons of material falls upon the Earth from space 
in the form of dust and meteorites. Over the past 20 years, U.S. government 
sensors have detected nearly 600 small asteroids, a few meters in size, 
which have entered the Earth's atmosphere and created spectacular bolides. 
The superbolide that impacted over Chelyabinsk, Russia in 2013 is estimated 
to have been 65 feet (20 meters) in size and released over 40 times the 
energy of the Arizona fireball. Impacts of that size take place a few 
times a century, and impacts of larger asteroids are expected to be far 
less frequent (on the scale of centuries to millennia) but can happen 
on any day.

NASA's Planetary Defense Coordination Office is responsible for finding, 
tracking, and characterizing near-Earth asteroids, identifying potentially 
hazardous objects, and planning for the mitigation of potential impacts 
to Earth that could do damage at ground level. More than 14,000 near-Earth 
asteroids (NEAs) have been discovered since NASA-sponsored efforts began 
in 1998 to detect, track and catalogue asteroids and comets.

[Video]
Video obtained from the NASA meteor camera situated at the MMT Observatory 
on the site of the Fred Lawrence Whipple Observatory, located on Mount 
Hopkins, Arizona, in the Santa Rita Mountains.
Credits: NASA/MEO

[Video]
This footage from the Sedona Red Rock Cam (part of the EarthCam network) 
shows how brightly the ground was illuminated during the fireball, which 
entered the atmosphere over Arizona shortly before 4 a.m. MST on June 
2, 2016.
Credits: Sedona Red Rock Cam/EarthCam

[Animation]
This animation shows the orbit of the June 2, 2016 Arizona fireball and 
the view from its perspective as it approaches Earth.
Credits: NASA/MEO