"We estimate that an asteroid of this size passes this close to the Earth only once every few decades."
The giant rock—half a football field wide—was first spotted by observers at the La Sagra Observatory in southern Spain a year ago, soon after it had just finished making a much more distant pass of the Earth at 2.6 million miles (4.3 million kilometers) away.
Chodas and his team have been keeping a close eye on the cosmic intruder, and orbital calculations of its trajectory show that there is no chance for impact.
But the researchers have not yet ruled out future chances of a collision. This is because asteroids of this size are too faint to be detected until they come quite close to the Earth, said Chodas.
The flyby of asteroid 2012 DA14 on Feb. 15, 2013, will be the closest known approach to Earth for an object its size.
Video produced by NASA/JPL-Caltech.
This NASA video explains just how close Asteroid 2012 DA14 will get to Earth, why you probably won't see it fly by, and how they're working on tracking other asteroids. Source: NASA/JPL-Caltech
"There is still a tiny chance that it might hit us on some future passage by the Earth; for example there is [a] 1-in-200,000 chance that it could hit us in the year 2080," he said.
"But even that tiny chance will probably go away within the week, as the asteroid's orbit gets tracked with greater and greater accuracy and we can eliminate that possibility."
Earth collision with an object of this size is expected to occur every 1,200 years on average, said Donald Yeomans, NEO program manager, at a NASA news conference this week.
DA14 has been getting closer and closer to Earth for quite a while—but this is the asteroid's closest approach in the past hundred years. And it probably won't get this close again for at least another century, added Yeomans.
While no Earth impact is possible next week, DA14 will pass 5,000 miles inside the ring of orbiting geosynchronous weather and communications satellites; so all eyes are watching the space rock's exact trajectory. (Learn about the history of satellites.)
"It's highly unlikely they will be threatened, but NASA is working with satellite providers, making them aware of the asteroid's pass," said Yeomans.
Packing a Punch
Experts say an impact from an object this size would have the explosive power of a few megatons of TNT, causing localized destruction—similar to what occurred in Siberia in 1908.
In what's known as the "Tunguska event," an asteroid is thought to have created an airburst explosion which flattened about 750 square miles (1,200 square kilometers) of a remote forested region in what is now northern Russia (map).
In comparison, an impact from an asteroid with a diameter of about half a mile (one kilometer) could temporarily change global climate and kill millions of people if it hit a populated area.
Timothy Spahr, director of the Minor Planet Center at Cambridge, Massachusetts, said that while small objects like DA14 could hit Earth once a millennia or so, the largest and most destructive impacts have already been catalogued.
A survey of nearly 9,500 near-Earth objects half a mile (one kilometer) in diameter is nearly complete. Asteroid hunters expect to complete nearly half of a survey of asteroids several hundred feet in diameter in the coming years.
"With the existing assets we have, discovering asteroids rapidly and routinely, I continue to expect the world to be safe from impacts in the future," added Spahr.
Meteors as Sun disturbances foretold for signs to science. There is one man who foretold of the record Sun flares of 2008 and of the now again record disturbances which come as many other signs for the waking and sounding to science of the Lord's Word called Science having reproved His Mystery as He prophesy of this day and Epic era of Destiny, for viewing the prewritten news events of this day which many of which have come and many other signs are now to come for viewing the exposed mystery of God go to the websites now mentioned below and visit all pages and links of undeniable waking truth and proof .... http://www.adamandeveseedgatheringministry.com/prophecy_and_the_signs for undeniable evidences of God's mystery being finished by Science of of the record eruptions on the Suns surface of 2008 being prewritten as well as the signs such as the Japan quakes and tidal wave and destruction there as the small tidal wave alaska which were prayed for to be small and alaska was the first other than Japan to receive tidal wave, and the Washington DC/Virginia Beach Virginia quakes which our Lord brought on the same day as the unofficial unveiling of the martin luther king statue in DC with more quakes coming there as we speak/read/write and all the signs listed therein were prophesy months before taking place for the belief of the Minister of the site being a Righteous man ... Respect to all of Adam/God
I'm amused by the word "expected" in the caption of the image. Does
the caption writer think we've identified the wrong asteroid? That
NASA has done the orbital calculations incorrectly? That somebody will
deflect the asteroid before closest approach?
All those possibilities would make the story much more interesting!
Well-composed piece over-all (it answered all my questions), though there are a couple of errors:
1. Tunguska was already northern Russia in 1908, not just "now".
2. "a millennium", not "a millennia"
And a couple of highly misleading statements:
1. As another commenter pointed out, 15 years of tracking is not enough to claim that it's the closest "in history" - even the article itself states that objects this size are estimated to come equally close every couple decades.
2. The asteroid is not "flying over the eastern Indian Ocean" in any normal sense of the expression. The entire Earth is less than 8,000 miles across - a fly-by at 17,200 miles leaves over two whole Earth-widths between the asteroid and the Indian Ocean. In other words, it will only be slightly closer to the Indian Ocean and Sumatra than it is to everything else in the same hemisphere.
Dear commentors, I do not know how to belay your fears any other way than just being direct; your fears are wrong and misleading. During the last two decades, through several means, (NASA and JPL and ESA) We have been using technigues to determine the trajectories of known objects VERY accurately. We have come a long way since Kepler. So, rest assured - when they say it is unlikely to hit ANYTHING - they mean it. It would be a VERY big surprise if the Earth gravity (which is now known, and calcuable, to less than a .04 deviation, at any given point) were to move the path of 2012 AD14 more than anticipated. We will have a slight collision possibility in 2036, so if we are here, we can analyze that encounter with much more scrutiny. Fear not Dooms-dayers, we will have that encounter - but not next week. In the mean time - google BTE Dan and get onboard. In the Kuiper Belt, we have a lot of things to analyze to ensure our survival.
Is there no risk? Geo-stationary satellites are positioned by the force of the Earth's gravitional field. They seem to hover in a stationary position because of Newtonian physics. The asteroid will pass inside the Earth's gravitational field and will be subjected to a force that could potentially bend the direction of the asteroid's orbit.
Closest Flyby in History if you define "History" as being the last fifteen years since NASA has been keeping track. The headline is a little sensational don't you think? C'mon, don't you have an editor there?
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