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New Evidence About 'The Great Dying' 250 Million Years Ago
PornMaster writes "The Guardian is reporting that scientists have found the first direct evidence that the killoff of 80% of land species and 95% of marine species 2 billion years ago was due to a meteor." The project web site has more info, maps, etc.
There wouldn't have been much on land at 2Ga.
The BBC have a much better version of the same story with addition information and some on the opposing view points BBC.co.uk
I stuck some data in the impact effects simulator (http://www.lpl.arizona.edu/impacteffects/), took reasonable guess at most of it. Anyone else more knowledgable, please correct.
Distance from Impact: 1000.00 km = 621.00 miles
Projectile Diameter: 28280.20 m = 92759.06 ft = 17.56 miles
Projectile Density: 3000 kg/m3
Impact Velocity: 30.00 km/s = 18.63 miles/s
Impact Angle: 45 degrees
Target Density: 3000 kg/m3
Target Type: Competent Rock or saturated soil
Energy:
1.60 x 1025 Joules = 3.82 x 109 MegaTons TNT
The average interval between impacts of this size somewhere on Earth is 2.6 x 109years
Crater Size:
Transient Crater Diameter: 173.30 km = 107.62 miles
Final Crater Diameter: 340.69 km = 211.57 miles
The crater formed is a complex crater.
Thermal Radiation:
Time for maximum radiation: 16.79 seconds after impact
Visible fireball radius: 425.5 km = 264.2 miles
The fireball appears 96.7 times larger than the sun
Thermal Exposure: 6.13 x 108 Joules/m2
Duration of Irradiation: 655 seconds
Radiant flux (relative to the sun): 936.0
Effects of Thermal Radiation:
Clothing ignites
Much of the body suffers third degree burns
Newspaper ignites
Plywood flames
Deciduous trees ignite
Grass ignites
Seismic Effects:
The major seismic shaking will arrive at approximately 200.0 seconds.
Richter Scale Magnitude: 11.0 (This is greater than any earthquake in recorded history)
Mercalli Scale Intensity at a distance of 1000 km:
VI. Felt by all. Many frightened and run outdoors. Persons walk unsteadily. Windows, dishes, glassware broken. Knickknacks, books, etc., off shelves. Pictures off walls. Furniture moved or overturned. Weak plaster and masonry D cracked. Small bells ring (church, school). Trees, bushes shaken (visibly, or heard to rustle).
VII. Difficult to stand. Noticed by drivers of motor cars. Hanging objects quiver. Furniture broken. Damage to masonry D, including cracks. Weak chimneys broken at roof line. Fall of plaster, loose bricks, stones, tiles, cornices (also unbraced parapets and architectural ornaments). Some cracks in masonry C. Waves on ponds; water turbid with mud. Small slides and caving in along sand or gravel banks. Large bells ring. Concrete irrigation ditches damaged.
Masonry C. Ordinary workmanship and mortar; no extreme weaknesses like failing to tie in at corners, but neither reinforced nor designed against horizontal forces.
Masonry D. Weak materials, such as adobe; poor mortar; low standards of workmanship; weak horizontally.
Ejecta:
The ejecta will arrive approximately 494.4 seconds after the impact.
Average Ejecta Thickness: 9.4 m = 30.83 ft
Mean Fragment Diameter: 5.4 mm = 0.2107 inches
Air Blast:
The air blast will arrive at approximately 3333.3 seconds.
Peak Overpressure: 920445.5 Pa = 9.2045 bars = 130.7033 psi
Max wind velocity: 661.5 m/s = 1479.8 mph
Sound Intensity: 119 dB (May cause ear pain)
Damage Description:
Multistory wall-bearing buildings will collapse.
Wood frame buildings will almost completely collapse.
Multistory steel-framed office-type buildings will suffer extreme frame distortion, incipient collapse.
Highway truss bridges will collapse.
Highway girder bridges will collapse.
Glass windows will shatter.
Cars and trucks will be largely displaced and grossly distorted and will require rebuilding before use.
Up to 90 percent of trees blown down; remainder stripped of branches and leaves.
stuff
This article is incorrect convieniently(sp?) enough I was listening to the NPR talk show yesterday and they very clearly said that is was 250 million years ago, which they said was the same that the tested core samples came out to be. They found the site they believed was it a crater on the sea floor with nearly a mile of dirt ontop of it, by using the same techniques that people looking for oil would. Incidentally the core samples were obtained 60 years ago while doing oil prospecting.
Hope that's atleast a little informative.
-RevSin
The article tells us that the event happened 250 million years ago.
It's always good to rtfa..
:^)
perl -e 'printf("%x!\n",49153)'
You know, there hasn't just been one great extinction in history. The dino-killer happened 65MYA. This article is talking about a much earlier event that happened 250MYA.
The comment in the article about the Chix . . . Chick . . . Mexican event refers to the idea that impact catastrophies may not have been the isolated event many assumed. Considering the large number of impact structures of up to several hundred kilometers in diameter around the world, it seems pretty obvious to me that it would have had a large effect on the development of life.
Most of these structures are so weathered that they aren't recognizable from the ground. For instance, the Chesapeake Bay on the east coast of the United States is a 90 km impact structure. Here are a couple of links about terrestrial impact structures. The second one is the best.
You're confusing the "great dying" of 250m years ago with the extinction of the dinosaurs 65m years ago. The Yucatan meteor has long been used as a possible explanation of the latter. This new crater off the coast of Australia is now seen as a possible explanation of the former.
You are using "old-school" ideas of abiogenesis to back yourself up. In fact, it is not very hard for organic compounds to self-organize into the needed components of life. Take for instance the cell membrane, this is a sphere of phospholipids. If one just takes phospholipids and adds them in water, they self-organize into a sphere and provide a membrane.
You may ask where these organic compounds came from, well a classic experiment (earned the researcher a Nobel prize I think) called the Miller-Urey experiment showed that if one simulated the conditions on a primordial earth, one got organic compounds (ranging from your simple alkanes to the building blocks of protiens, amino acids) were formed. And these processes happen relatively quickly, thus I do not see the evolution of life as being improbable.
If any of my facts are wrong please correct, if you want back-up for my statements, feel free to request it.