NASA is collecting space dirt from an asteroid that could kill us all

The Bennu asteroid could show us the origins of the solar system, or it could be the death of us all. Either way, NASA's OSIRIS-REx is going to touch it to find out.

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By Claire Reilly, CNET

If Earth is going to get wiped out by an asteroid in the next couple of hundred years, Bennu could be the one to do it. 

Officially known as 101955 Bennu, the asteroid is about the size of the Empire State Building and has a "not-insignificant probability of impacting the Earth," according to NASA. In fact, Bennu is ranked second on the Palermo Technical Impact Hazard Scale -- effectively Earth's rankings of "what's going to wipe us all out"?

So if we had a chance to visit it, surely we'd send a ragtag team of miners to blow it up, rather than travelling seven years to collect a bit of space dirt off the top? 

But remember, this is NASA we're talking about!

In this week's episode of Watch This Space, we take a look at OSIRIS-REx -- NASA's mission to make contact with Bennu (for all of five seconds) to collect asteroid dust from the surface and bring it back to Earth. 

It might sound like a long way to go for a bit of dust, but this material (known as "regolith") could tell us a lot. According to NASA, asteroids are essentially "the leftover debris from the solar system formation process," so their composition can shed light on the history of our the solar system, how it was formed and even how planets like Earth came to be. 

OSIRIS-REx (that stands for Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer spacecraft) arrived at Bennu on Dec. 3 and will spend a little less than a year surveying the asteroid for a suitable space to touch down. When it's found the perfect spot, the spacecraft will make contact with the surface of the asteroid for about five seconds, sending a blast of nitrogen gas to disturb dust and pebbles on the surface to capture in the spacecraft and bring back to earth. 

At the end of its seven-year mission, NASA scientists will be able to examine this material and learn more about where we came from and potentially even find "molecular precursors to the origin of life and the Earth's oceans" according to NASA. 

If you want to learn more about the other amazingly cool stuff NASA and other space agencies are up to, you can check out the full Watch This Space series on YouTube.