Meteorites strike Earth every few months
GERMANY: A meteor exploded in the sky above Russia last
Friday, causing a shockwave that blew out windows injuring hundreds of
people and sending fragments falling to the ground in the Ural
Mountains. Here’s a look at those objects in the sky — what’s the
difference between a meteor and a meteorite?
Meteors are pieces of space rock, usually from larger comets or
asteroids, which enter the Earth’s atmosphere. Many are burned up by the
heat of the atmosphere, but those that survive and strike the Earth are
called meteorites. They often hit the ground at tremendous speed up to
30,000 km an hour, according to the European Space Agency. That releases
a huge amount of force.
Experts say smaller strikes happen five to 10 times a year. Large
impacts such as the one Friday in Russia are rarer but still occur about
every five years, according to Addi Bischoff, a mineralogist at the
University of Muenster in Germany.
What caused the damage in Russia?
Alan Harris, a senior scientist at the German Aerospace Centre in
Berlin, said most of the damage would have been caused by the explosion
of the meteor as it broke up in the atmosphere. The explosion caused a
shockwave that sent windows and loose objects flying through the air in
a radius of several kilometres. By the time the remaining fragments hit
the ground they would have been too small to cause significant damage
far from the site of impact, he said.
Is there any link to the asteroid flyby taking place later Friday?
No, it’s just cosmic coincidence, according to European Space Agency
spokesman Bernhard von Weyhe, who says Asteroid 2012DA14 is unrelated to
the meteorite strike in Russia.
When was the last comparable meteorite strike?
In 2008, astronomers spotted a meteor heading toward Earth about 20
hours before it entered the atmosphere. It exploded over the vast
African nation of Sudan, causing no known injuries. The largest known
meteorite strike in recent times was the “Tunguska event” that hit
Russia in 1908. Even that strike, which was far bigger than the one that
happened over Russia on Friday, didn’t injure anyone.
What can scientists learn from the Urals strike?
Bischoff says scientists and treasure hunters are probably already
racing to find pieces of the meteorite. Some meteorites can be very
valuable, selling for up to €500 ($670) per gram depending on their
exact composition.
Because meteors have remained largely unchanged for billions of years
unlike rocks on Earth that have been affected by erosion and volcanic
outbreaks scientists will study the fragments to learn more about the
origins of matter. Mr. Harris, of the German Aerospace Centre, says some
meteorites are also believed to carry organic material and may have
influenced the development of life on Earth.
THE HINDU |