Meteorites strike Earth every few months, and the Russian blast is not related to the asteroid that's flying by Friday.
BERLIN
— A meteor exploded in the sky above Russia on Friday, injuring
hundreds of people as its fragments fell 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
18,642 mph, according to the European Space Agency. That releases a huge
amount of force.
How common are meteorite strikes?
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. Most of these strikes happen in uninhabited areas
where they don't cause injuries to people.
Is there any link to the asteroid fly-by 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.
Scientists
believe that an even larger meteorite strike may have been responsible
for the extinction of the dinosaurs about 66 million years ago.
What can scientists learn from Friday's 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 $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.
What would happen if a meteorite hit a major city?
Scientists
hope never to find out, but they're still trying to prepare for such an
event. Von Weyhe, the European space agency spokesman, says experts
from Europe, the United States and Russia are already discussing how to
spot potential threats sooner and avert them.
"It's a global
challenge, and we need to find a solution together," he said. "But one
thing's for sure, the Bruce Willis 'Armageddon' method won't work."
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