The NEO Code -What Global Hotspots are Most at Risk Of Getting Hit by an Asteroid?
The team used raw data from multiple impact simulations to rank each country based on the number of times and how severely they would be affected by each impact. The software, called NEOimpactor (from NASA's "NEO" or Near Earth Object program), has been specifically developed for measuring the impact of 'small' asteroids under one kilometer in diameter.
Early results indicate that in terms of population lost, China, Indonesia, India, Japan and the United States face the greatest overall threat; while the United States, China, Sweden, Canada and Japan face the most severe economic effects due to the infrastructure destroyed.
The top ten countries most at risk are China, Indonesia, India, Japan, the United States, the Philippines, Italy, the United Kingdom, Brazil and Nigeria.
“The consequences for human populations and infrastructure as a result of an impact are enormous,” says Bailey. “Nearly one hundred years ago a remote region near the Tunguska River witnessed the largest asteroid impact event in living memory when a relatively small object (approximately 50 metres in diameter) exploded in mid-air. While it only flattened unpopulated forest, had it exploded over London it could have devastated everything within the M25. Our results highlight those countries that face the greatest risk from this most global of natural hazards and thus indicate which nations need to be involved in mitigating the threat.”
The team is also examining how the consequences of an impact change with increasing impact energy. Initial results indicate that a 100 meter diameter asteroid will predominantly cause localized casualties and damage across a few countries when impacting on either land or ocean. However, the consequences of a 200 meter diameter asteroid hitting the ocean increase significantly, with the generated tsunamis reaching a global scale. At 500 meters in diameter, almost any ocean impact will generate significant casualties and economic cost across the world.
As Stephen Hawking says, the general consensus is that any comet or
asteroid greater than 20 kilometers in diameter that strikes the Earth
will result in the complete annihilation of complex life - animals and
higher plants. (The asteroid Vesta, for example, one of the
destinations of the Dawn Mission, is the size of Arizona).
How
many times in our galaxy alone has life finally evolved to the
equivalent of our planets and animals on some far distant planet, only
to be utterly destroyed by an impact? Galactic history suggests it
might be a common occurrence.
The first this to understand about
the KT event is that is was absolutely enormous: an asteroid (or comet)
six to 10 miles in diameter streaked through the Earth's atmosphere at
25,000 miles an hour and struck the Yucatan region of Mexico with the
force of 100 megatons -the equivalent of one Hiroshima bomb for every
person alive on Earth today. Not a pretty scenario!
Recent
calculations show that our planet would go into another "Snowball
Earth" event like the one that occurred 600 million years ago, when it
is believed the oceans froze over (although some scientists dispute
this hypothesis -see link below).
While microbial bacteria might
readily survive such calamitous impacts, our new understanding from the
record of the Earth's mass extinctions clearly shows that plants and
animals are very susceptible to extinction in the wake of an impact.
Impact
rates depend on how many comets and asteroids exist in a particular
planetary system. In general there is one major impact every million
years -a mere blink of the eye in geological time. It also depends on
how often those objects are perturbed from safe orbits that parallel
the Earth's orbit to new, Earth-crossing orbits that might, sooner or
later, result in a catastrophic K/T or Permian-type mass extinction.
The asteroid that hit Vredefort located in the Free State Province of
South Africa is one of the largest to ever impact Earth, estimated at
over 10 km (6 miles) wide, although it is believed by many that the
original size of the impact structure could have been 250 km in
diameter, or possibly larger(though the Wilkes Land crater in
Antarctica, if confirmed to have been the result of an impact event, is
even larger at 500 kilometers across). The town of Vredefort is
situated in the crater (image).
Dating back 2,023 million
years, it is the oldest astrobleme found on earth so far, with a radius
of 190km, it is also the most deeply eroded. Vredefort Dome Vredefort
bears witness to the world’s greatest known single energy release
event, which caused devastating global change, including, according to
many scientists, major evolutionary changes.
What has kept the
Earth "safe" at least the past 65 million years, other than blind luck
is the massive gravitational field of Jupiter, our cosmic guardian,
with its stable circular orbit far from the sun, which assures a low
number of impacts resulting in mass extinctions by sweeping up and
scatters away most of the dangerous Earth-orbit-crossing comets and
asteroids
Posted by Rebecca Sato
Highly Recommended:
Pacific-Ocean-Sized Explosion On Jupiter Highlights Stephen Hawking's "Asteroid" Theory
Note: This post was adapted from a news release issued by University of Southampton.




Oops, in the ninth paragraph I think you meant to say "100 million megatons", otherwise Tsar Bomba was fully half as powerful as the KT extinction event! :D
Posted by: Qev | September 08, 2009 at 08:18 AM
Are we at risk?
electronic cigarette
Posted by: Jil H | September 08, 2009 at 10:58 AM
Qev is right the impact power of a monster of 15-25Km diametre is thought to be NOT les that 100 Million megatons ....OR more ....depending on the impact angle.
That kind of an impact would generate a super E.L.E.
Tens of millions of Years for living species to recover and populate again the planet
God save us.
Regards to space guards
Posted by: claudio | September 11, 2009 at 01:31 PM
Regarding Hawking's idea about a 20km asteroid killing off life, there is the wilkes land crater in Antarctica that may have been caused by a 47km object, and led to the Permian extinction.
A 20 km object of silicate composition with a closing speed of 18 km/s would have an impact energy of 2.03 x 10^24 Joules, or 500 million Megatons.
Posted by: Tom | March 12, 2011 at 05:11 PM