NASA Asteroid Expert Explains How Earth Could Be Saved From Dangerous Space Rocks (VIDEO)

Sci-fi flicks that star Earth-killing space rocks, such as the 1998 movie "Armageddon" or "Deep Impact," might be Hollywood fantasy, but according to astronomers, those silver-screen scenarios could become reality.

Given that there are "potentially hazardous asteroids" NASA has mapped out, scientists are continuing to scan skies just in case. In fact, NASA announced a new "grand challenge" in June to find all dangerous space rocks as well as a way to stop them from destroying Earth.

How exactly do you stop an asteroid in its tracks? I reached out to Lindley Johnson, program executive for the Near-Earth Object Program Office at NASA headquarters in Washington D.C., for the answer -- check it out in the video above, or click the link below for a transcript. And don't forget to sound off in the comments section at the bottom of the page. Talk nerdy to me!

JACQUELINE HOWARD: Hey everyone. Jacqueline Howard here. Several astronomers all around the world are scanning the skies on a regular basis, pointing high-tech telescopes toward the cosmos, taking note of what’s zipping by our planet while remaining on alert. So, what are they looking for? Dangerous asteroids. Particularly, a giant global killer that may have our name on it. Scary, right?! But not necessarily unlikely. We all saw what happened in Chelyabinsk, Russia, when that meteor exploded in the sky, causing damage and injuries back in February. How big is the risk that something similar may happen again -- or even something worse? Well to find out, I spoke with Lindley Johnson. He’s the program executive for NASA’s near-Earth objects office in Washington, D.C.

LINDLEY JOHNSON: In fact, I just looked the number up, 10,081, near-Earth objects have been cataloged that we are tracking. However, there’s a number of them that are considered potentially hazardous. In other words, they are objects that do come close to Earth's orbit. So they bear watching.

JH: Not only could they drift really close to us, but ‘potentially hazardous’ also means they’d be more than 100-meters wide, so possibly big enough to pass through Earth’s atmosphere and cause damage on a regional scale. Yikes! And there may still be space rocks out there we haven’t even spotted yet. So, what happens if we see something heading our way? How do we protect ourselves?

LJ: Most of the studies show that there are probably three leading techniques that might be used. The principle of much of these mitigation techniques, deflection techniques, is to change the speed that the asteroid is traveling in space.”

JH: So, Lindley said technique number-one is using a kinetic impactor, something like a projectile or rocket, that would smack into a space rock at high velocity causing it to veer off course. Kaboom! Other studies suggest a weighted robotic spacecraft could just kind of nudge an asteroid off course. Technique number two is using the force of gravity itself to change a space rock’s path. That could be done by flying a big spacecraft out to the asteroid, so they’re right next to each other, and then hopefully the gravitational attraction between the two would be strong enough to deflect the asteroid. But with both of those options, it would take years -- some scientists estimate around a decade -- to pull together the capabilities, travel out to the space rock, and allow time for the rock’s trajectory to change. And then we’ve got technique number-three, which is total destruction, basically blow up the space rock with some explosive. Now, if we had to put one of these plans into action -- who would be orchestrating all of this?

LJ: We have been working within the form of the United Nations, with their committee on Peaceful Uses of Outer Space, as a working group. We have been developing procedures and protocol by which the nations would work together should we discover an impact threat, how we would respond as an international community.

JH: Ah, got it. This all kind of makes me think about that 1998 sci-fi flick ‘Armageddon’ -- or better yet, the movie ‘Deep Impact.’ You know, while those were Hollywood fantasy, what do you think would be the best way to save our planet from a killer asteroid in real life? Come on, talk nerdy to me!

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