NZ
media went out of its way to deny that this event was connected with
asteroids. The question in my mind is, what do RUSSIAN scientists say about this.
Russian
'meteor' was actually a tiny asteroid, NASA says
At
a news conference Friday, NASA scientists said the object that
exploded over Russia was a “tiny asteroid” that measured roughly
45 feet across, weighed about 10,000 tons and traveled about 40,000
mph.
15
February, 2013
The
object vaporized roughly 15 miles above the surface of the Earth,
causing a shock wave that triggered the global network of listening
devices that was established to detect nuclear test explosions.
The
force of the explosion measured between 300 and 500 kilotons,
equivalent to a modern nuclear bomb, according to Bill Cooke, head of
the Meteoroid Environment Office at NASA's Marshall Space Flight
Center in Huntsville, Ala.
“When
you hear about injuries, those are undoubtedly due to the events of
the shock striking the city and causing walls to collapse and glass
to fly, not due to fragments striking the ground,” Cooke said.
Scientists
believe the object originated from the asteroid belt, a vast
collection of debris orbiting between Mars and Jupiter that consists
of leftover bits from the formation of the solar system. The asteroid
probably traveled for a year before it burst into the atmosphere
Friday. As yet, no fragments have been recovered, but experts believe
the asteroid was rocky in nature, and not formed of dense iron and
nickel.
The
fact that the asteroid hit on the same day that the world was
anticipating the close flyby of a larger asteroid, 2012 DA14, was an
extraordinary coincidence. The smaller asteroid was traveling in a
very different trajectory and much more quickly than DA14, indicating
they were not related, according to Paul Chodas, research scientist
in the Near-Earth Object Program office at NASA's Jet Propulsion
Laboratory in La CaƱada Flintridge.
“I
would call this a tiny asteroid,” Chodas said. ”This is the
largest recorded event since the Tunguska explosion in 1908.” That
event, which may have involved a meteor, leveled more than 800 square
miles of forest in Russia.
Asteroids
are tracked by telescope, as they are too far away to be detected by
radar. Because of this, they are observable only when illuminated by
the sun against a dark background. If they are small and
dark-colored, they are far more difficult to observe. In the case of
the Russian asteroid, it approached Earth with the sun behind it.
“The
reason it wasn’t detected by telescopes on Earth is because it
literally came out of the daylight sky and, as you know, telescopes
can’t see things in the daytime,” Cooke said.
Scientists
estimate that anywhere between 80 and 200 tons of space-borne debris
hits Earth’s atmosphere every day. Most of those objects are the
size of a grain of sand. Objects that contact the Earth’s surface
are much rarer.
NASA
leads international efforts to track much larger, asteroid-size
objects, and Chodas said the agency had identified 95% of them. It’s
the smaller ones that pose a problem. “They are very difficult to
find,” he said.
[Updated,
6:30 p.m. Feb. 15: An earlier version of this post said that NASA had
estimated the size of the object to be at least 7,000 tons, which it
later revised to about 10,000 tons. This version also clarifies that
the force of the explosion was roughly equivalent to a modern nuclear
bomb, much larger than the weapons that exploded in Hiroshima and
Nagasaki, Japan, in 1945.]
From RT
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