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Judi Lynn

(160,219 posts)
Tue Mar 19, 2019, 09:27 PM Mar 2019

Surprise! 'Active Asteroid' Bennu Is a Rare Particle-Ejecting Space Rock

Surprise! 'Active Asteroid' Bennu Is a Rare Particle-Ejecting Space Rock
By Mike Wall 3 hours ago Science & Astronomy

Only a dozen of these cosmic oddballs are currently known.



This view of the asteroid Bennu ejecting particles from its surface on Jan. 19, 2019, was created by combining two images taken by NASA's OSIRIS-REx spacecraft: a short-exposure photo, which shows the asteroid clearly, and a long-exposure version, which shows the particles clearly. Other image-processing techniques were also applied, such as cropping and adjusting the brightness and contrast of each layer.(Image: © NASA/Goddard/University of Arizona/Lockheed Martin)


The near-Earth asteroid Bennu is a lot weirder and more interesting than scientists had thought.

The 1,650-foot-wide (500 meters) space rock ejected particles of dust and gravel into space multiple times over the past few months, newly announced observations from NASA's OSIRIS-REx spacecraft reveal. So, Bennu is one of just a dozen or so known "active asteroids" — and the only one to be observed up close.

The discovery "is probably the biggest surprise of the early stages of the OSIRIS-REx mission and, I would say, one of the biggest surprises of my scientific career," OSIRIS-REx principal investigator Dante Lauretta, of the University of Arizona, said during a news conference today (March 19).

The $800 million OSIRIS-REx mission launched in September 2016 and arrived in orbit around Bennu on Dec. 31 of last year. If all goes according to plan, in mid-2020, the probe will dip down and grab a sample of Bennu material, which will come down to Earth in a return capsule in September 2023.

More:
https://www.space.com/asteroid-bennu-active-osiris-rex-discovery.html?utm_source=notification

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