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Old 04-08-2017, 05:05 PM
nuke11 nuke11 is offline
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Here are the details of the asteroid used in the 4th edition (this information was cut). I received this from Robert back in November 2013.

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.
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