150-foot asteroid will buzz Earth, no need to duck (Update 2)

February 7, 2013 by Marcia Dunn
This image provided by NASA/JPL-Caltech shows a simulation of asteroid 2012 DA14 approaching from the south as it passes through the Earth-moon system on Feb. 15, 2013. The 150-foot object will pass within 17,000 miles of the Earth. NASA scientists insist there is absolutely no chance of a collision as it passes. (AP Photo/NASA/JPL-Caltech)

A 150-foot(45-meter)-wide asteroid will come remarkably close to Earth next week, even closer than high-flying communication and weather satellites. It will be the nearest known flyby for an object of this size.

But don't worry. Scientists promise the megarock will be at least 17,100 miles (27,518 kilometers) away when it zips past next Friday.

"No Earth impact is possible," Donald Yeomans, manager of NASA's Near-Earth Object program at Jet Propulsion Laboratory in Pasadena, California, said Thursday.

Even the chance of an asteroid-satellite run-in is extremely remote, Yeomans and other scientists noted. A few hundred satellites orbit at 22,300 miles (35,886 kilometers), higher than the asteroid's path, although operators are being warned about the incoming object for tracking purposes.

"No one has raised a red flag, nor will they," Yeomans told reporters. "I certainly don't anticipate any problems whatsoever."

Impossible to see with the naked eye, the asteroid is considered small as these things go. By contrast, the one that took out the dinosaurs 65 million years ago was 6 miles (9.6 kilometers) wide.

Yet Asteroid 2012 DA14, as it's known for its discovery date, still could pack a wallop.

If it impacted Earth—which it won't, scientists were quick to add Thursday—it would release the energy equivalent of 2.4 million tons of TNT and wipe out 750 square miles (1,942 square kilometers). That's what happened in Siberia in 1908, when forest land around the Tunguska River was flattened by a slightly smaller asteroid that exploded about five miles above ground.

The likelihood of something this size striking Earth is once in every 1,200 years. A close, harmless encounter like this is thought to occur every 40 years.

The bulk of the solar system's asteroids are located between the orbits of Mars and Jupiter, and remain stable there for billions of years. Some occasionally pop out, though, into Earth's neighborhood

The closest approach of this one will occur next Friday afternoon, Eastern time, over Indonesia.

Graphic showing the flybys of asteroids and comets to come in 2013, starting on February 15. An asteroid will zoom within spitting distance of Earth next week, in what NASA said is the closest flyby ever predicted for an object this large.

There won't be much of a show. The asteroid will zip by at 17,400 mph (28,000 kph). That's roughly eight times faster than a bullet from a high-speed rifle.

The asteroid will be invisible to the naked eye and even with binoculars and telescopes will appear as a small point of light. The prime viewing locations will be in Asia, Australia and eastern Europe.

Observers in the U.S. can pretty much forget it. Astronomers using NASA's deep-space antenna in California's Mojave Desert will have to wait eight hours after the closest approach to capture radar images.

Scientists welcome whatever pictures they get. The asteroid offers a unique opportunity to observe something this big and close, and any new knowledge will help if and when another killer asteroid is headed Earth's way.

The close approach also highlights the need to keep track of what's out there, if for no other reason than to protect the planet.

NASA's current count of near-Earth objects: just short of 10,000, the result of a concentrated effort for the past 15 years. That's thought to represent less than 10 percent of the objects out there.

No one has ruled out a serious Earth impact, although the probability is said to be extremely low.

"We don't have all the money in the world to do this kind of work" for tracking and potentially deflecting asteroids, said Lindley Johnson, an executive with the Near-Earth Object observations program in Washington.

Indeed, when asked about NASA's plans to send astronauts to an asteroid in the decades ahead, as outlined a few years ago by President Barack Obama, Johnson said the space agency is looking at a number of options for human explorations.

One of the more immediate steps, planned for 2016, is the launch of a spacecraft to fly to a much bigger asteroid, collect samples and return them to Earth in 2023.

As for Asteroid 2012 DA14—discovered last year by astronomers in Spain—scientists suspect it's made of silicate rock, but aren't sure. Its shape and precise size also are mysteries.

What they do know with certainty:

"This object's orbit is so well known that there's no chance of a collision," Yeomans repeated during Thursday's news conference.

Its close approach, in fact, will alter its orbit around the sun in such a way as to keep it out of Earth's neighborhood, at least in the foreseeable future, Yeomans said.

Johnson anticipates no "sky is falling thing" related to next week's flyby.

He and other scientists urged journalists to keep the close encounter in perspective.

"Space rocks hit the Earth's atmosphere on a daily basis. Basketball-size objects come in daily. Volkswagen-size objects come in every couple of weeks," Yeomans said.

The grand total of stuff hitting the atmosphere every day? "About 100 tons," according to Yeoman, though most of it arrives harmlessly as sand-sized particles.

Explore further: Small asteroid swings harmlessly past Earth (Update)

More information: NASA: www.nasa.gov/topics/solarsyste … s/asteroidflyby.html
University of Arizona: osiris-rex.lpl.arizona.edu/


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5 / 5 (8) Feb 07, 2013
"The asteroid measures about 150 feet (45 kilometers) in diameter."
150 feet = 45 km, now I am reassured.
3.8 / 5 (10) Feb 07, 2013
This is result of a half effort conversion to the metric system in the 70s and a growing scientifically illiterate population in the US - apparently including NASA.
3.6 / 5 (5) Feb 07, 2013
Dug - No, just an error in the mysterious system called "decimal points."
3.3 / 5 (7) Feb 07, 2013
NASA estimates ... but only hits the Earth once every 1,200 years.

Statistically-speaking, that means we're probably safe for quite a while, since a similar asteroid hit just over 100 years ago.
Oh? OK! This writer wasn't at school the day they talked about statistics.
5 / 5 (2) Feb 07, 2013
"150 feet = 45 km..."
Nice catch, canuckit! The writer missed by only about 28 miles.
5 / 5 (4) Feb 08, 2013
Bad article. The "150 feet = 45 km" is careless. But this is worse:

"Statistically-speaking, that means we're probably safe for quite a while, since a similar asteroid hit just over 100 years ago."

This sentence shows a breathtaking ignorance of probability theory. Face-palm! The writer probably thinks that if you flip a coin and get heads, the odds of getting tails on the next flip increases.

The Tunguska impact does not assure us of an impact-free near future.

I can scarcely believe finding nonsense like this at Phys.org. Puh-lease.
1.7 / 5 (12) Feb 08, 2013
This is result of a half effort conversion to the metric system in the 70s and a growing scientifically illiterate population in the US - apparently including NASA.

I live in the USA. I think the metric system should be shipped back across the ocean where it came from. If the rest of the world wants to sell their goods here, they need to convert to the USA system of measurement - or go sell their goods elsewhere.

not rated yet Feb 08, 2013
Has the Tunguska event ever been confirmed to have been a meteorite impact?
not rated yet Feb 08, 2013
According to wikipedia, that is the most likely explanation. There are a number of other proposed hypothesis, but they all seem a bit too much crackpotty. Like black holes, h-bombs and antimatter
1 / 5 (5) Feb 09, 2013
The footage on the NASA site of the video of the Spanish astronomers' recording of the "asteroid's" progress shows it clearly avoiding some kind of space rock in its path. This is not an asteroid, and it is running late of the Dec 21, 2012 ETA. The occupants could be either like the Martians is "Mars Attacks!", or they could be like Jesus. We don't know, and what are we gonna do?
1 / 5 (1) Feb 09, 2013
Has the Tunguska event ever been confirmed to have been a meteorite impact?

Yes, it is generally agreed that is an impact event. Kulic's expedition in 1928 pretty much confirmed it then, and I believe subsequent expeditions managed to harvest particles from the impacter that were inbedded in trees directly below the site of the explosion.
1 / 5 (2) Feb 10, 2013
hmm is a 45m asteroid a high concern even if it entered atmosphere? i can imagine a 45m cube but it doesn't seem that impressive :).
1 / 5 (1) Feb 11, 2013
hmm is a 45m asteroid a high concern even if it entered atmosphere? i can imagine a 45m cube but it doesn't seem that impressive

We can often imagine stuff that size, but the stuff we compare it to in our minds (large buildings, aircraft carriers and the like) - are really just empty air with comparatively thin stone/steel wrappers.

We're talking MASSIVE stone, here. And this is one reason why the idea of blowing up largish asteroids with nukes is just a pipe dream. Yes, you can destroy something the size of a skyscraper with a nuke, because it's mostly a hollow shell. But if it's even slightly bigger, and massive, then a nuke will barely scratch it.
1 / 5 (2) Feb 11, 2013
never expected nukes to destroy asteroid, my thoughts were that the impact would be able to change their trajectory.

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