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September 7, 2016

At first glance, the asteroid Bennu seems pretty benign. It’s about a third of a mile across, and it’s probably a loose agglomeration of rock and ice. And because it contains a lot of carbon, it’s darker than a charcoal briquette. Yet Bennu isn’t quite as innocuous as it seems, as Arizona astronomer Ed Beshore explains:

BESHORE: It is one of the most threatening of all asteroids right now. It has roughly a one-in-a-thousand chance of hitting Earth late in the 22nd century, which is a pretty high chance when it comes to asteroid impacts.... It’s about a 500- to 600-meter-wide asteroid. Because of that, if it did hit the Earth, it would actually be a pretty destructive event. It probably wouldn’t be a civilization-threatening event, but it would be catastrophic.

Beshore is one of the lead scientists for a spacecraft that’s scheduled to study the asteroid. OSIRIS-Rex will launch as early as this week. After a long cruise, it’ll spend about two years flying along with Bennu. Then it’ll drop to the surface and pick up some dust and pebbles for return to Earth.

The main goal is to study the asteroid, which is a leftover from the birth of the planets. But a secondary goal is to develop techniques for maneuvering around an asteroid. Such techniques might be needed if Bennu or any other asteroid is found to be on a collision course with Earth — keeping our planet safe from one of the hazards of the solar system.

Script by Damond Benningfield

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