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Will another Tunguska event happen on Feb. 15? Asteroid 2012 DA14 to set a dubious record

By Marshall Connolly, Catholic Online (NEWS CONSORTIUM)
February 4th, 2013
Catholic Online (www.catholic.org)

An asteroid about 50 yards across will speed past Earth faster than a bullet on Feb. 15, and the shave will be so close that it will pass beneath many satellites in Earth orbit. Scientists promise there is no chance for a collision.

LOS ANGELES, CA (Catholic Online) - In 1908 an event took place over remote Siberia known today as the "Tunguska event." Scientists speculate that an asteroid or cometary fragment exploded in the atmosphere above the heavily-forested wilderness. It leveled an estimated 80 million trees. The impact was about 1,000 times more powerful than the atomic bomb that would be dropped on Hiroshima 37 years later.

People living miles away from the air burst reported being thrown to the ground by the shockwave with some victims temporarily losing hearing and vision. The blast and subsequent shaking, much like an earthquake, shattered windows. Instruments as far away as London detected the blast.

Such an impact could have destroyed an entire city.

Now, a similarly-sized rock is passing very close. In fact, it is the closest approach of an asteroid in recorded history.

Scientists have been watching Asteroid 2012 DA14, since it was discovered last year by amateur astronomers from Spain. The close approach has been of concern because of its tremendous destructive power. However, scientists stressed that even if the asteroid were on track to strike Earth, it would be unlikely to cause any substantial damage - given the likelihood that it would not land on a major metropolitan area. While it's dangerously sized, it's not a planet killer by any stretch.

Nonetheless, its discovery caused quite a stir.

Most scientists see the close approach as an opportunity to educate the public about the threat from asteroid impacts. While significant impacts are quite rare, happening only every several thousand years or so on average, major impacts can occur every several million years and have the potential to devastate life on the planet.

Scientists now believe that a major asteroid impact which took place 65 million years ago was so powerful and threw so much dust and debris into the atmosphere, that it killed the dinosaurs and most other life on the planet. By virtue of natural selection, a few small and lucky warm-blooded mammals survived this event and its freezing aftermath, which persisted for years.

Scientists know that Asteroid 2012 DA14 isn't so dramatic, but it is a typical asteroid and worth study. As it zips past the Earth on Feb. 15, ground-based radar will attempt to map the asteroid. Researchers want to know as much as they can find about the asteroid, including its true size, mass, composition, spin, and reflectivity.

Answering these questions can provide scientists with information that would be useful for devising solutions for improving detection of these objects. Detection is key because astronomers believe that another Tunguska event will happen again. They also believe that a major extinction-level event such as that which killed the dinosaurs will also happen again. It is simply a matter of time.

For now, those timescales are measured in thousands to millions of years.

Yet, what happens if a major object is discovered that's on a collision course with Earth? Knowing more about Asteroid 2012 DA14 will help engineers develop ways that might possibly deflect such a threat.

For now, humanity can breathe a sigh of relief and go about its business with relief. Asteroid 2012 DA14 doesn't pose a threat. A Tunguska-like event may happen again, but it's not going to be because of Asteroid 2012 DA14.

Still, it's nice to know there are dedicated teams of astronomers keeping an eye out for the rest of us, and scientists dedicated to learning more about the cosmos, hopefully ensuring that we too escape the dinosaurs' fate, should it someday come to that.

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