These are brief
descriptions of realistic scenarios involving the impact of a typical stony
meteor/asteroid of various sizes. The diameter in meters or kilometers
is given, as well as a statement regarding the atmosphere's effect upon
the asteroid, followed by a brief description of the event and several
sentences describing the consequences. You might be amazed at the magnitude
of the destruction by something so small, but this is tied to the fact
that the impact velocities vary from 10 km/s to 72 km/s (22,000 mph to
0.1 m: fireball, with deceleration to terminal velocity
A meteorite the size of a large grapefruit smashed through the roof
of a suburban high school outside of Paris today, striking a science teacher
on the hip and causing massive bruises over the lower part of his body.
Students working on astronomy projects in the same room were unharmed.
This is only the second instance in recorded history of a person being
struck by a meteorite. Scientists who rushed to examine the stony meteorite
said that it undoubtedly originated on the surface of Mars. Microscopic
examination of the meteorite may provide new evidence in the ongoing controversy
over the possibility of life on the red planet.
3 m: fireball, with deceleration to terminal velocity
METEORITE LANDS NEAR FISHERMAN'S WHARF; CRUSHES MIME.
At 5:00 PM this afternoon, a enormous fireball was observed over the
west coast of the United States. The fireball appeared to break apart in
mid-air over San Francisco. Seconds later, an iron meteorite weighing nearly
a hundred tons crashed into the front of a T-shirt store near San Francisco's
famed Fisherman's Wharf, crushing a mime in the middle of a performance
and creating a hole nearly ten feet deep. It is the largest such meteorite
ever seen, surpassing the 34-ton Ahnighito meteorite discovered in Greenland,
and the 66-ton Hoba meteorite of Africa.
Although native San Franciscans seemed unimpressed, a crowd of tourists
immediately gathered around the meteorite, and discovered to their surprise
that it was cool to the touch. Speculating about why such a massive object
had not made a larger hole, a prominent scientist theorized that it had
entered the Earth's atmosphere at a very low angle, allowing its speed
to be slowed by atmospheric friction.
Rush-hour traffic jams in central San Francisco were observed to be
unusually severe in the aftermath of the fall.
50 m: airburst after sudden shock at the troposphere
2:00 PM Tuesday: A giant meteorite exploded in the atmosphere six miles
above San Francisco today, creating a shock wave which is estimated to
have destroyed every building within a five-mile radius. The heat from
the blast ignited a firestorm which incinerated most of San Francisco,
causing thousands of deaths. Cars were overturned and windows shattered
as far away as Sacramento.
In spite of worldwide asteroid-detection efforts in recent years, astronomers
had no warning of the incoming meteorite, which was too small to be picked
up by the most advanced telescopes until moments before it hit.
As appalling as the damage was, scientists say we were lucky. This one
was a stony meteorite. If it had been made of iron, like the one which
created the Barringer Crater in Arizona, it would have vaporized San Francisco
and devastated most of northern California.
700 m: land impact, with little deceleration
At approximately 8:15 this evening, Asteroid 2004 Cyrus struck the
Earth 5 km west of Paris, France. Since the discovery of its trajectory
and impending impact about six months ago, the governments of Western Europe
have done their best to relocate the populations of France, Belgium, Luxembourg
and the Netherlands.The force of the impact, equal to that of 50,000,000,000
tons of TNT, annihilated the city of Paris in an instant. The shock wave
from the explosion flattened large areas of London, Brussels, Antwerp andAmsterdam,
while the intense heat ignited firestorms across much of France. The cloud
of smoke and dust from the explosion and fires is expected to alter the
climate of the Earth for a period of months or years, causing crop failures
and possible mass starvation.
700 m: ocean impact, with little deceleration
At approximately 11.45 this morning GMT (night time in Japan) a meteorite
landed 500 miles south of Tokyo in the Pacific Ocean. Giant tsunamis have
destroyed all coastal and island areas for thousands of miles. Damage is
devastating for the islands of Japan, the Korean peninsula and much of
Northern China. Death tolls are expected to reach as high as 100 million.
Specific damage reports are as of yet unavailable.
1.7 km: land impact, with virtually no deceleration
At approximately 4:27 this morning EDT Asteroid 2004 Cyrus landed on
New York City. Since the discovery of its trajectory and impending impact
about one year ago the governments of the US and Canada have done their
best to relocate the populations of areas within 500 miles of New York
City. With the force of its blast estimated at 1,000,000,000,000 tons of
TNT, the shockwave flattened buildings over much of New England and the
Mid-Atlantic states. Firestorms are raging across the eastern United States
as far as the Mississippi, creating a cloud of smoke and dust
which will create life-threatening weather conditions worldwide. Predictions
are for global cooling on the order of 4-8 degrees celsius (8-20 degrees
Fahrenheit). Massive crop failures may lead to global starvation and hundreds
of millions of additional deaths.
1.7 km: ocean impact, with virtually no deceleration
At approximately 10.15 this morning GMT (night time in Japan) a meteorite
landed 500 miles south of Tokyo in the Pacific Ocean. Giant tsunamis full
of churning debris have destroyed all coastal and island areas for hundreds
of thousands of square miles. All of Japan and the Korean peninsula, along
with much of China, the Philippines and Indonesia have been totally destroyed,
with the loss of over a billion lives.
At this moment, 300-foot high tsunamis are heading for the Pacific coasts
of North and South America. Chaos is reported as millions of terrified
people attempt to flee the advancing wall of water, which may sweep
inland as much as a hundred miles. The long-term environmental consequences
of the impact are as yet unpredictable, but are likely to be devastating.
It should be noted that currently we cannot detect
asteroids of these sizes unless they pass within distances corresponding
to a few Earth-Moon distances. A reasonably good census of asteroidal objects
exists for diameters exceeding 12 km or so, depending upon the reflectivity
(and so composition) of the asteroid. This situation should change for
the better in the near future. Anything that large hitting the Earth, however,
would devastate most forms of advanced life. Luckily, most of the orbiting
debris out there is very small, usually vaporizing in our atmosphere to
give us a harmless shooting star display. But while the chances
of one of these larger objects hitting the Earth are slim, they are not
zero, and the consequences are enormous. Any risk analysis takes into account
probability of occurence as well as the impact (no pun intended) of a positive
result. These scenarios, and others, can be found at this web