The “city killers” are small. They are not big and easily seen, like a
tiger in the jungle. They are more like
bullets. And that is why they are killers. We do not detect them until they are hurtling
at us with no way for us to avoid calamity.
On February 15, 2013 a city killer exploded over
Russia. That one, the Chelyabinsk
meteor, was the most well-documented meteor event in history. The Chelyabinsk meteor was also—by far—the
largest such event since the 1908 meteor explosion over Tunguska, Russia, which
knocked down something near 80 million trees in a remote forest. A plethora of video recordings emerged immediately
following the Chelyabinsk event. And,
frankly, that meteor scared the hell out of everyone, including scientists at NASA
and a host of others standing at the small end of telescopes watching the
firmament.
Those in the know have been anxiously watching another
class of asteroids called “world enders.”
The city killers frighten these observers.
Collaborating from various places around the world, astrophysicists
have located and tracked something like 95 percent of the world ender asteroids
flung all around us. The world enders are
more than a half-mile in size and large enough to be found at a distance. Once found, they are monitored. A world ender could, at a minimum, lead to
mass extinction. Some credit a world
ender with the mass extinction of dinosaurs. But the smaller asteroids—those less than a
half-mile-wide (the city killers)—are unnamed and untracked.
The city killer that entered the atmosphere on
February 15, 2013 was estimated at about 50 feet wide (about the size of a bus)
and weighed about 10,000 tons. It streaked
into our atmosphere at 40,000 miles-per-hour before exploding in the air 10 to
15 miles above the Russian city of Chelyabinsk.
The explosion was estimated to be 20-30 times more powerful than that of
the atomic bombs detonated aver Hiroshima and Nagasaki. Windows were blasted out of many buildings in
the area near the blast. At least one
building experienced a partial collapse.
About 1,500 people were injured by flying objects propelled by the shock
wave following the blast.
Interestingly, the same day that the Chelyabinsk asteroid
(turned meteor by entering the atmosphere) exploded over Russia, a much larger
city killer passed us by in a near-miss.
That Asteroid, travelling at about half the speed of the one that
entered our atmosphere (but still faster than a bullet) was about half the size
of a football field and weighed about 130,000 tons. The asteroid crossed between Earth and the
orbital shell where our satellites are placed in the space above us. The asteroid zipped past Earth 5000 miles
closer to us than our own satellites.
That asteroid, by the way, was a chance discovery made by amateur astronomers.
Maybe we could nudge one of the world enders
off-track at a distance with a nuclear warhead launched from our planet and
thus live to drink another glass of Scotch.
But the city killers are small and difficult to detect. Some of us might want to keep some Scotch
close at hand in the event of a bright flash of light in the sky.
--Mitchell
Hegman
A FEW CLIPS FROM RUSSIA:
Good one Mitchell - I have loved reading many of the NASA articles and of course, follow astronomical events as a hobby. Great desciption in your blog.
ReplyDeleteThank you, sir!
ReplyDelete