Quote:
Originally Posted by RandyT0001
Does it say where the Giant Asteroid hits the surface of the Earth? Does it say how big, specifically in miles or kilometers, the Giant Asteroid is? Does it give information about the composition (nickel/iron, stone, frozen gases, etc.) of the Giant Asteroid, its angle of intersection with the Earth and/or its velocity at intersection with the Earth?
Knowing the size, composition, intersection angle and velocity one can simulate the impact on one of several meteor impact calculators online. Placement of the impact has a effect also. An impact in the western Pacific ocean will affect those countries with a tsunami whereas a strike in central Africa will create a different ejecta with different effects on the world.
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Here is some information posted to the MP List by one of the authors. I would guess we will be seeing it as some sort of expansion or addendum in the future as it was cut from the pre-press edition.
He used the following websites to calculate the effects;
HTML Based:
http://impact.ese.ic.ac.uk/ImpactEffects/
Java Based :
http://simulator.down2earth.eu/
Some information about the calculator:
http://www.universetoday.com/38384/a...ct-calculator/
I used the impact effects program you have linked to earlier, and the papers that form the bases for the equations used in the calculator. Key references are listed at the end of this post.
So we have a 5km diameter asteroid (density 3 g/cc) striking the mid-Pacific Ocean (water depth 4km) at 17 km per second at 45 degrees angle of incidence.
Impact energy: about 10 million megatons equivalent.
Blast: 1psi radius 2,800km
Full thickness burn radius 850km
Earthquake: magnitude 9.4 with epicentre impact point. Damage present in an area about the size of the United States - this just makes the seas more violent around the impact area in this case.
Firestorms: upper atmospheric heating due to re-entry of ejecta over the first few hours. This acts like an oven for up to 4 hours. Peak surface temperatures in the worst affected areas are up to 200 degrees C (392 F).
Some self-shielding from cloud formations moderate the effect in some regions. This occurs over half the earth.
Tsunamis: Waves of 10-20m push up to 30km inland along every coastline on the Pacific Ocean up to 10 hours after impact (propagation speed 600-900km/h).
* Effects of several months duration:
- Darkness for first month due to atmospheric dust loading - photosynthesis is impossible in worst affected regions (most of the world). It gets
*cold* - Last Glacial Maximum levels (5C - 9F drop in global average temperatures in the first 2 weeks).
- Recovery of optical transparency over next 6 months
- Local cooling due to atmospheric soot loading (fires) - washout leads to acid rain.
Acid rain aggravated by nitrogen oxides produced in impact.
* Effects of several years duration:
- Ozone reduction from NOx reaching stratosphere - global declines and worsening of known 'ozone holes'.
- Cooling due to persistent stratospheric dust loading and sulphate injection analogous to volcanos.
This maintains the initial depressed temperatures generated from injected dust.
- Acid rain as sulphate and dust is cleared
* Effects of several decades duration:
- Warming from stratospheric injection of water and carbon dioxide from the impact event. This may be limited by high-altitude clouds increasing albedo.
All this is absolutely catastrophic - but it's not the Chicxulub impact
(~100 million megatons) which caused global acidification of the oceans - the impact site was rich in sulphur containing minerals - in addition to all the above effects at greater intensity and duration. Which appears to be the 'no land creature bigger than 10kg survives' level.
* References
G.S. Collins, H.J. Melosh, and R.A. Marcus. Earth Impact Effects Program: A Web-based computer program for calculating the regional environmental consequences of a meteroid impact on Earth. Meteoritics and Planetary Science 40, Nr 6, 817-840 (2005)
O.B.Toon, R.P. Turco, C.Covey et al. Environmental Perturbations Caused by the Impact of Asteroids and Comets. Reviews of Geophysics 35:1 (Feb. 1997) 41-78.
T.J. Goldin, H.J. Melosh. Self-shielding of thermal radiation by Chicxulub impact ejecta: Firestorm or fizzle? Geology 2009;37;1135-1138
D.A. Kring. The Chicxulub impact event and its environmental consequences at the Cretaceous-Tertiary boundary. Palaeogeopgraphy, Paleoclimatology, Palaeoecology 255 (2007) 4-21
J.W. Birks, P.J. Crutzen, R.G. Roble. Frequent ozone depletion resulting from impacts of asteroids and comets. In 'Comet/Asteroid Impacts and Human Society' P. Bobroswky and H. Rickman eds. Springer Verlag 2005.
C.R. Chapman, D.D. Durda and R.E. Gold. The Comet/Asteroid Impact Hazard: A Systems Approach. Feb. 2001. SwRI white paper:
www.boulder.swri.edu/clark/neowp.html