20日地球被一两米直径流星(某未知彗星碎块)以每秒24英里速度击中

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NASA Sky Cameras Capture Man-Sized Meteor Over Macon, Ga.

http://www.nasa.gov/topics/solarsystem/features/watchtheskies/macon.html

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05.23.11 Meteor over Macon, Ga., on the evening of May 20, 2011. (NASA/MSFC/MEO)

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Ground track of meteor's path. (Google)

Astronomers at NASA's Marshall Space Flight Center have recorded the brightest meteor seen by their network in almost three years of operation. On May 20, 2011, at 9:47 p.m. CDT, a six-foot diameter fragment of an unknown comet entered the atmosphere approximately 66 miles above the city of Macon, Ga., traveling northwest at a speed of some 24 miles per second (86,000 mph). At this velocity, the boulder-sized "dirty snowball" possessed an energy or striking power somewhere between 500-1000 tons of TNT.

This was seen by many eyewitnesses in Georgia and Alabama; the American Meteor Society has some of the reports here:


http://www.amsmeteors.org/fireball2...05-31&state=&event_id=511&submit=Find+Reports

It was tracked by two NASA all sky cameras, one located in Chickamauga, Ga., and the other at the Tellus Science Museum in the town of Cartersville, Ga. Analysis of the video data from these cameras enabled the Meteoroid Environment Office to estimate the trajectory, speed, mass and orbit of the meteor. More information on these cameras and a log of recent meteor events can be found at: http://fireballs.ndc.nasa.gov.

Fortunately the atmosphere provided us with excellent protection, as the video below illustrates. Because the video is slowed to one-third of the actual real-time speed, it's easy to spot the large fragments coming off in the wake after the flares.

The video shows four distinct flares caused by the meteor breaking apart in its fiery final few seconds. You can see fragments coming off in the meteor's wake after three of these flares. After a last burst of light, the meteor ablated -- or "burned up" -- 38 miles above the town of Villa Rica, Ga., located on the border between Carrol and Douglas counties in Georgia.

[ame="http://www.youtube.com/watch?v=-8v8-nQoRNk"]YouTube - ‪NASA - NASA Sky Cameras Capture Man-Sized Meteor Over Macon, Ga.‬‏[/ame]


NASA Media Contact:
Janet Anderson, 256-544-0034
NASA Marshall Space Flight Center, Ala.
Janet.L.Anderson@nasa.gov
 
太阳系正穿行于宇宙的枪林弹雨之中--两周前才发生的彗星撞太阳的壮观场面:

http://www.nasa.gov/multimedia/videogallery/index.html?media_id=89090701

Bye, Bye Comet

SOHO watched as a fairly bright comet dove towards the Sun in a white streak and was not seen again after its close encounter (May 10-11, 2011). The comet, probably part of the Kreutz family of comets, was discovered by amateur astronomer Sergey Shurpakov. In this coronagraph the Sun (represented by a white circle) is blocked by the red occulting disk so that the faint structures in the Sun's corona can be discerned. Interestingly, a coronal mass ejection blasted out to the right just as the ...
[ame="http://www.youtube.com/watch?v=4TzqKUMzie4"]YouTube - ‪bye bye comet‬‏[/ame]
 
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