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Friday, February 15, 2013

Asteroid 2012 DA14 Heading Toward Planet Earth

You've probably been reading about Asteroid 2012 DA14 which is headed for a close encounter with earth this Friday night, February 15th. DA14 is about 150 feet in diameter and will whiz by the earth at a distance of some 17,200 miles, within the ring of geosynchronous satellites that orbit the earth. Yes, this is a close call, but the asteroid will not strike the earth or any satellites in orbit around the earth. So, what will happen as it sails by? Nothing, nothing at all. Call it a close miss. But you will be able to observe this fast moving celestial body from Israel, starting at about 10:00PM local time and lasting through the early hours of Saturday morning.

The chart below shows the expected path of 2012 DA14 through the skies above Israel with time ticks representing Greenwich Mean Time. Add two hours to convert to Israeli local time.  Although it will move quickly compared to most celestial bodies because it is so close to earth, you will still not see it move at the speed of a plane or even satellite. As you can see from the chart, it will take over eight hours to go from the tail of Leo to the NorthStar. So, you will only be able to identify it by its motion if you watch for an extended period of time. You will also need binoculars since at a brightness between magnitude 7 and 8 it will not be a naked eye object.


Asteroid 2012 DA14's path through the skies above Israel. Timing ticks are in Greenwich Mean Time (GMT) so you will have to add two hours to find the asteroid's position in Israeli local time. It will shine between magnitude 7 and 8, so you will need binoculars or a telescope to see it.
If it's cloudy or you don't want the challenge of finding it outside, many observatories around the world will be live-streaming the event.  Israel's own Bareket Observatory is offering a free live webcast of the close approach on February 15 beginning at 10:15 Israeli local time, for a duration of about 3 hours. For more information, visit Baraket Observatory’s website. You’ll be automatically transfered to the live images, during the event.

NASA Television will provide commentary starting at 9:00PM Israeli local time on February 15. The commentary will be streamed live online at http://www.nasa.gov/ntv and http://www.ustream.tv/nasajpl2  

An object this size, thought to have a mass of 130,000 metric tons, would pack an explosive force of about 2.4 megatons of TNT if it struck the earth. The atomic bomb that leveled Hiroshima packed a blast of .02 megatons, so this asteroid could pack a wallop 120x as large as Little Boy. While not a planet killer, like the asteroid that struck the Yucatan Peninsula 65 million years ago and wiped out the dinosaurs, it is still something to be reckoned with. Fortunately, over 70% of the earth is water and there are still significant wilderness areas, so chances are it would strike an unpopulated area. Still it would be difficult to predict its actual strike zone, creating world-wide fear and uncertainty. This is the reason astronomers now scan nightly for Near Earth Objects (NEOs) in attempt to locate them before they strike the earth. The geological record shows that on average an "earth killer" asteroid strikes our planet every 50 million years. The last one was the Yucatan Peninsula strike some 65 million years ago, so we are about 15 million years overdue for extinction, in case you needed something else to worry about.

The last time an object this large struck the earth was the mysterious Tunguska Event of June 30, 1908, when a comet, some think asteroid, struck a remote region of Siberia and laid waste to a vast area of forest. Asteroids about 150 feet in diameter are thought to be about the size of the one that struck Arizona about 50,000 years ago, creating the great Meteor Crater which is 3/4 of a mile wide and 500 feet deep.



The orbit of asteroid 2012 DA14, shown looping within the orbits of the moon and the ring of geosynchronous satellites that orbit the earth. A close call!


Update: February 16, 2013

This video was taken by Francois Colas at Pic du Midi Observatory in France. It is a time lapse of 15 minutes of travel compressed into 16 seconds.





2012 DA14 2013 feb 15th Pic du Midi from Francois Colas on Vimeo.




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1 comment:

  1. It is realy a close encounter!! At the speed of 13km/sec, it should be roughly (6*60*60*13=2,80,800km) roughly distance of moon!! I hope the velocity is the relative velocity of it w.r.t earth. With the enormous gravity of earth, the object may change its course considerably and we should also take into account the gravity of moon. Let us hope it does not become a sattelite of earth, in which case its collision with earth may be inevitable.!! Let us pray god!!

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