Asteroid Near-Miss: Why It Matters

A 150-foot asteroid estimated to weigh 143,000 tons offered astronomers and armchair audiences alike a rare spectacle when it whizzed close by the Blue Planet on Friday.

The chunk of space rock, discovered by amateur astronomers in Spain and not-so-catchily dubbed 2012 DA14, moved Friday closer to us than ever before. That happened near the Indonesian island of Sumatra at about 2:24 p.m. ET. The asteroid will still be visible as it moves away from earth this evening.

Here's what you should know about the asteroid's historic travels and why you should count yourself lucky.

A historic flyby

Flybys like Friday's only occur once every 40 years.

This one was by far the closest that DA14 will come to Earth for many decades, NASA says. The next closest will be 33 years from now, when it won't come within 620,000 miles from Earth's center.

The closest the asteroid came Friday was within 17,200 miles, over 5,000 miles closer than the group of GPS and weather satellites that rings the planet.

Dr. Dante Lauretta, principal investigator for NASA's OSIRIS-REx asteroid investigation, told NBC Washington before the flyby there was "absolutely nothing to worry about."

"The asteroid will not hit the earth," he said. "It will not hit the space station. It’s not going to hit any of our critical satellite assets -- so you don’t have to worry about losing your TV.”

Still, the flyby was unusually close, which is why the asteroid prompted such intense interest, not only from scientists and curious stargazers but also from private companies that smell profits in the space rocks.

Scientists from firms like Deep Space Industries have recently been eying such asteroids as the future of alternative fuel, with resources like hydrogen, oxygen, nickel and iron.

"Would you rather rip the heart out of a living mountain to get the metals you need, or go mine an asteroid that’s just a piece of dead rock that’s going to kill us if we don’t eat it?" its board chairman said last month.

What if it hit Earth?

If it did collide with the planet, the asteroid's impact could have been enough to wipe out the entirety of New York City, plus a good chunk of its suburbs.

Asteroids the size of DA14 only hit Earth every 1,200 years or so, The Associated Press reported. The last major asteroid impact hit in in 1908 — in the middle of the Siberia, mercifully, rather than near a city. The impact by that asteroid, about the same size as the DA14, unleashed a massive TNT blast — more than 1,000 times more powerful than the atomic bomb dropped on Hiroshima — and obliterated 750 square miles of forest.

In a separate development early Friday, nearly 1,000 people were injured when a huge fireball believed to be a meteorite fell over Russia's Chelyabinsk region, causing an explosion and sonic boom that shattered glass windows.

The Russian Academy of Sciences estimated the meteor weighed about 11 tons before entering the Earth's atmosphere with a speed at least 33,000 mph, according to BBC News.

Astronomy experts said the event was not connected to DA14's flyby, having come from a different trajectory.

Earth gets hit by several tons of material every day but most of it burns up in the atmosphere, Lisa Will, resident astronomer at the California-based Fleet Science Center, told NBC 7 San Diego.

A meteor the size of the fireball in Russia occurs possibly every couple of months but statistically ends up in water so humans don’t see a lot of them, Will added.

If 2012 DA14 were to hit Earth, the impact would be far more powerful, NBC News reported.

NASA scientists stressed before the flyby that wouldn't happen, but that's not to say they're not worried about possible future impacts.

The agency's Near Earth Object Observation program finds and tracks asteroids and comets near earth and keeps track of them all to see if any could threaten Earth. For those it fears might, it's also working on technology to deflect the asteroids from their paths.

How can I watch 2012 DA14?

Not by looking skyward, unless you're in Europe, Asia or Australia and you've got a telescope or binoculars. In that case, there are websites that can tell you where, when and how to look.

That's important because of parallax. DA14 is passing so close to the Earth that people in different parts of the world will have to look in different parts of the sky to see the rock.

NASA carried a livestream with views of the asteroid from Australia that included commentary as it passed its closest point to earth.

A three-hour live online feed of the flyby from a telescope at NASA's Huntsville, Ala., facilities starts at 9 p.m. ET on Friday, too.