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You probably didn't notice, but one of the most dangerous asteroids on record whizzed past Earth last month, luckily closely avoiding us.

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Though it begs the question: What would we do if an asteroid were on a collision course with our planet?

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Tom Foreman reports scientists are looking at novel ways to deal with that threat.

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Amid all this popular talk about the idea that an asteroid could hit the earth one day, NASA has a very serious proposal:

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Why not go into space and try to capture one so we can learn more about asteroids?

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And this is how they propose to do that.

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A very powerful rocket would take off from Earth and it would launch what's called an asteroid redirect vehicle,

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which is essentially a robotic spacecraft which would shoot off into space driven by the most powerful solar electric propulsion system we've ever seen.

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Now, it wouldn't actually go beyond the stars,

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but this does give a sense that it would go many, many hundreds of thousands of miles off into space,

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looking for a very small target, because the asteroids they're after would only be about this big, as big as two or three big pick-up trucks,

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although this would weigh as much as two freight train engines. And it would be rotating slowly.

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That's a challenge because they have to stop that before they transport it.

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So, let me scale this down to size so you have a better idea of what we're talking about.

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Because as the redirect vehicle comes toward it, it will deploy a giant technical space bag.

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And over a period of hours, gradually ease that over the rotating asteroid and squeeze down on it to stop that rotation.

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Then the whole shebang will take off, flying back toward the earth, and more importantly, toward the moon

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where it would go into a rotation around the moon about 40,000 miles above the lunar surface.

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This way, scientists could travel out there, astronauts, to visit this asteroid and conduct experiments on it.

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Why we do this, though?

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This will cost many, many billions of dollars at a time when the country doesn't have much money.

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Well, the scientific community says,

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because it will give us very important knowledge about new deep-space technologies, propulsion systems, solar energy --

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all sorts of things that we use all the time on Earth.

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Secondly, it would actually give us an idea of what to do if we had an asteroid coming toward Earth.

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We've handled one. We'd have some idea how to handle another.

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And just as importantly, we would find out what sort of minerals and things are contained inside these asteroids,

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whether or not that's something we could mine for purposes on Earth

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or perhaps to be used in future exploration further into space.

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Bottom line, they say, yes, it's expensive, but it's called exploration because you never really know what you might find.