Welcome back to Tech Blog Tuesday at Johns Hopkins University! We're excited to be starting up the tradition again in 2013. Posts will be coming more frequently and stem from a variety of hot-button topics.
Last Friday, two very interesting events happened to the Earth and the immediate region in space surrounding it. One, the asteroid classified as 2012 DA14 passed by Earth at a distance of 17,210 km, which is closer than the moon is to the Earth. It's the first time an object of this size has been detected before it passed this close, and was discovered last year by a Spanish telescope.
But it wasn't the only thing in the sky that day.
The second space-relevant thing to happen last Friday was the meteor that entered into the atmosphere over Russia, flew overhead at about 20 miles at 40,000 miles per hour, released a ton of energy, and injured about 1,200 people from its shock-wave. When you learn very few people have ever been injured by meteors, coupled with the frequency of a meteor impact of this size is once every century,you begin to realize how astronomically small the odds of this incident happening are--pun intended.
For all those who wonder if the Russian meteor was somehow related to 2012 DA14, consider the fact that the asteroids came from opposite directions. “There is no relation there,” said Paul Chodas, a scientist with NASA’s Near Earth Object Program. “It seems like we’re in a cosmic shooting gallery here. There were two very rare events happening on the same day. Pure coincidence.”
Russian witnesses describe the meteor's fall as a streak across the sky, with a smoke trail "similar to a jet's but much larger." The mach-52.5 meteor caused an immense disturbance in the air surrounding it as it plummeted, creating a huge shock wave that traveled slower than the light and roaring sound of the meteor. Many were drawn to the windows by its intense and unearthly light, but when the windows imploded from the shock wave, hundreds were showered with broken glass. It is for this reason that so many were injured, not because the meteor exploded and hit people.
The Russian science community says the meteor was about 10 feet wide and weighed about 10 tons, but American estimates based on low-frequency sensors put the meteor at a much larger size: 50 feet wide and 7,000 tons. Based on the differences in the reported values, it is possible that the density of the asteroid is unusually high, causing huge disturbances in the low-frequency sensors. More will be known once the landing place of the meteor is discovered, but considering it exploded as it passed over, that may be more difficult than it originally sounds.
Although it exploded 15-20 miles above the ground (higher than the troposphere, the part of the atmosphere that contains all weather), it still unleashed a huge amount of energy equivalent to about 300,000 tons of TNT. To put that into perspective, the Hiroshima bomb was about 15,000 tons of TNT in destructive power.
Even when you assume the Russian's small size estimate, a rock traveling at that speed and that size could cause a crater about a kilometer (.62 miles) in diameter. When geologists find it, they'll have a field day. It's a huge chance to study something new and exciting, something to always hope for!
Last Friday, two very interesting events happened to the Earth and the immediate region in space surrounding it. One, the asteroid classified as 2012 DA14 passed by Earth at a distance of 17,210 km, which is closer than the moon is to the Earth. It's the first time an object of this size has been detected before it passed this close, and was discovered last year by a Spanish telescope.
 |
NASA/JPL-Caltech/Associated Press -
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 Friday, 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.
|
But it wasn't the only thing in the sky that day.
The second space-relevant thing to happen last Friday was the meteor that entered into the atmosphere over Russia, flew overhead at about 20 miles at 40,000 miles per hour, released a ton of energy, and injured about 1,200 people from its shock-wave. When you learn very few people have ever been injured by meteors, coupled with the frequency of a meteor impact of this size is once every century,you begin to realize how astronomically small the odds of this incident happening are--pun intended.
For all those who wonder if the Russian meteor was somehow related to 2012 DA14, consider the fact that the asteroids came from opposite directions. “There is no relation there,” said Paul Chodas, a scientist with NASA’s Near Earth Object Program. “It seems like we’re in a cosmic shooting gallery here. There were two very rare events happening on the same day. Pure coincidence.”
Russian witnesses describe the meteor's fall as a streak across the sky, with a smoke trail "similar to a jet's but much larger." The mach-52.5 meteor caused an immense disturbance in the air surrounding it as it plummeted, creating a huge shock wave that traveled slower than the light and roaring sound of the meteor. Many were drawn to the windows by its intense and unearthly light, but when the windows imploded from the shock wave, hundreds were showered with broken glass. It is for this reason that so many were injured, not because the meteor exploded and hit people.
 |
| A photo provided by Chelyabinsk.ru shows the meteor’s trail over Chelyabinsk on Friday. Its passage unleashed sonic booms. |
Although it exploded 15-20 miles above the ground (higher than the troposphere, the part of the atmosphere that contains all weather), it still unleashed a huge amount of energy equivalent to about 300,000 tons of TNT. To put that into perspective, the Hiroshima bomb was about 15,000 tons of TNT in destructive power.
Even when you assume the Russian's small size estimate, a rock traveling at that speed and that size could cause a crater about a kilometer (.62 miles) in diameter. When geologists find it, they'll have a field day. It's a huge chance to study something new and exciting, something to always hope for!
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