NASA

[Hum]

PASADENA, Calif. ? At first glance, Don Yeomans looks like your friendly suburban neighbor. But behind the calm and cool exterior, the NASA scientist has one of the most important jobs imaginable: finding the galaxy?s deadliest asteroids before they pose a threat to all life on Earth.

The prevailing view among scientists is that a giant asteroid hit the Earth about 65 million years ago, wiping out nearly all life, including the dinosaurs. And according to many of those same experts, it?s only a matter of time before another extinction-level event occurs.

Thankfully, the world is being kept safe by Yeomans, NASA?s very own asteroid hunter.

Yeomans, 70, who was recently named one of Time Magazine?s 100 Most Influential People Alive, told Yahoo News about the science behind asteroid hunting, how he finds them and NASA?s plan to make sure the ?big one? never makes it to Earth.

In the 1998 film ?Armageddon,? NASA discovers that a Texas-size asteroid is headed straight for Earth and we only have 18 days to stop it. So how does that scenario compare to reality?

?Well, that movie was definitely pure fiction,? Yeomans told Yahoo News in an interview at NASA?s Jet Propulsion Laboratory in Pasadena.

?First of all, there aren?t any asteroids in near Earth space that are anywhere near the size of Texas. And if there were, we would certainly find it decades, perhaps even 100 years, in advance of any close Earth approach,? he said.

For years, Yeomans has led NASA?s efforts to detect these so-called near Earth objects. He says they?ve found about 95 percent of them and that the space organization is prepared to deal with any that should pose a threat.

?You have to get an object about 30 meters in size or larger, about a third the size of a football field, or larger, before it can actually cause ground damage,? Yeomans said.

But should an object that big hit the Earth, even a skeptic like Yeomans describes the scenario as a ?hellish environment? that would almost certainly wipe out humanity.

Such an impact would ?shut out much of the sunlight and kill the plants, of course. You?ve got acid rain, you?ve got re-entering fiery ejecta,? Yeomans said. ?You?ve got a pretty hellish environment.?

Based on the odds alone, it?s somewhat remarkable that a giant asteroid hasn?t wiped us out already.

more