• Fireball Lights Pre-Dawn Sky over Arizona

    From baalke@1:2320/100 to sci.space.news on Fri Jun 3 00:16:08 2016
    From Newsgroup: sci.space.news

    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

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