NASA | Swift and Hubble Probe an Asteroid Crash

Late last year, astronomers noticed that an asteroid named Scheila had unexpectedly brightened and it was sporting short-lived plumes. Data from NASA's Swift satellite and Hubble Space Telescope show that these changes likely occurred after Scheila was struck by a much smaller asteroid.

On Dec. 11, 2010, images from the University of Arizona's Catalina Sky Survey, a project of NASA's Near Earth Object Observations Program, revealed the Scheila to be twice as bright as expected and immersed in a faint comet-like glow. Looking through the survey's archived images, astronomers inferred the outburst began between Nov. 11 and Dec. 3.

Three days after the outburst was announced, Swift's Ultraviolet/Optical Telescope (UVOT) captured multiple images and a spectrum of the asteroid. Ultraviolet sunlight breaks up the gas molecules surrounding comets; water, for example, is transformed into hydroxyl (OH) and hydrogen (H). But none of the emissions most commonly identified in comets -- such as hydroxyl or cyanogen (CN) -- show up in the UVOT spectrum. The absence of gas around Scheila led the Swift team to reject scenarios where exposed ice accounted for the activity.

Images show the asteroid was flanked in the north by a bright dust plume and in the south by a fainter one. The dual plumes formed as small dust particles excavated by the impact were pushed away from the asteroid by sunlight. Hubble observed the asteroid's fading dust cloud on Dec. 27, 2010, and Jan. 4, 2011.

The two teams found the observations were best explained by a collision with a small asteroid impacting Scheila's surface at an angle of less than 30 degrees, leaving a crater 1,000 feet across. Laboratory experiments show a more direct strike probably wouldn't have produced two distinct dust plumes. The researchers estimated the crash ejected more than 660,000 tons of dust--equivalent to nearly twice the mass of the Empire State Building.

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  Science & Technology

[CaNaDiiAnBaCoN]

Religion is the reason why we can't afford to take you into space to prove it to you. 500b a year on war? Caused by religion.

[Mosgaard]

More science please! Love those episodes

[TheWizardJeff]

We are not being visited by aliens!!!

[LoneSniperFox]

0:38 it's not a comet. It's a REAPER

[hagenhh1]

nice video, keep it up!

[hagenhh1]

very interesting video.

[hagenhh1]

great video. i don't believe in ufos btw.

[gpgpgp13322]

you must be the most stupidest person on Earth of cause it exists you dumb ass go preach some where els in fact go die no one wants to here you preach

[gpgpgp13322]

fucking hate religion!

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[gregoryvn3]

Nice!

[astrophonix]

Shame they missed the opportunity to point out that asteroid belts, or ours at least, are nowhere near as incredibly dense as Star Wars portrayed, it's more like the chances of getting hit by a rock is 3,720 to 1 against. We've already sent about ten probes through the belt without any problem.