Asteroids, meteors shower Earth’s atmosphere Friday
Published: Tuesday, February 19, 2013
Updated: Tuesday, February 19, 2013 02:02
Two major asteroid events occurred on Friday, one over a small Russian town and the other in the upper regions of the Earth’s atmosphere. On the same day that the asteroid DA14 passed through Earth’s atmosphere — just beneath some orbiting satellites — a meteor crashed over Chelyabinsk, Russia. While the passing of DA14 had been foreseen by scientists months ago, the meteor in Russia was completely unexpected by the scientific community.
James Ryan is a professor of physics and space at UNH and had been preparing a lecture when he heard about the Russian meteor on the radio.
“(We) never get two of these things in a day except today,” Ryan said.
Asteroids, such as DA14, are rocks that are outside the Earth’s atmosphere, like the material in the asteroid belt. Meteors, like the one that struck Russia, are asteroids that fall through the Earth’s atmosphere and are also called shooting stars. Asteroids are generally given names while meteors aren’t. As Ryan noted, when two related happenings occur in the same day, keeping them straight in conversation gets tricky.
One of the important things about the meteor in Russia was the footage caught of it. According to Ryan, a large number of meteors that fall to Earth simply go unnoticed by people.
“Most of the Earth is reasonably unpopulated,” he said. “Three quarters of it is ocean. There are big chunks where no one lives, but this one hit near a populated area. If this had happened over the Pacific, people may not have known about it.”
Because it struck so close to a populated area, many people got video footage of the meteor from a wide variety of angles as it fell. Less than an hour after it hit, YouTube was filled with videos of the meteor burning through the sky and the explosive effect of the shockwave.
“Because people got smartphones, that’s new. Before, it was very rare to get video of something like this. Now when this thing fell over many miles, many people who can get a video of it,” Ryan said.
According to a NASA press release, it only took the Russian meteor 32.5 seconds to fall through the atmosphere. The meteor was 55 feet wide (15 feet wider than a school bus), weighed over 10,000 tons, and ended its flight with a 500 kiloton explosion (equal to 30 Hiroshima bombs). The shockwave released broke windows throughout the surrounding area and injured roughly 1,000 people.
“The one that hit Russia is smaller in size, so it’s hard to see, and when you can see it, it’s really close, coming really fast,” Ryan said.
Silent by comparison, asteroid DA14 entered and exited the Earth’s atmosphere without issue, with its closest approach coming 17,200 miles over Indonesia. DA14 is half the size of a football field, and scientists say that if it had collided with the Earth, the explosion would have been strong enough to destroy a city the size of London.
“The asteroid (DA14) is 15,000 times bigger than the one that struck Russia,” Ryan said. “We don’t want to be hit by that asteroid (DA14).”
Despite the unlikelihood of having two major asteroid events occur in the same day, scientists are positive that the two asteroids are unrelated. According to a NASA press release, the two asteroids came in at completely different trajectories, barring any possibility that they were connected.