Page 1 of 1

LSAT's greatest controversy now settled

Posted: Sun Mar 07, 2010 3:25 pm
by chewdak
"04 Mar 2010

Asteroid killed off the dinosaurs, says international scientific panel
The Cretaceous–Tertiary mass extinction, which wiped out the dinosaurs and more than half of species on Earth, was caused by an asteroid colliding with Earth and not massive volcanic activity, according to a comprehensive review of all the available evidence, published today in the journal Science."

http://www3.open.ac.uk/media/fullstory.aspx?id=18308

Re: LSAT's greatest controversy now settled

Posted: Sun Mar 07, 2010 3:31 pm
by pjo
if this is true where is the hole left from the impact? When meteroites hit earth they leave a crater 7-10 times the size of the meteor itself. if the asteroid was 15 kilometers there should be a hole somewhere in mexico anywhere from 105-150 kilometers wide

Re: LSAT's greatest controversy now settled

Posted: Sun Mar 07, 2010 3:35 pm
by BLi
pjo wrote:if this is true where is the hole left from the impact? When meteroites hit earth they leave a crater 7-10 times the size of the meteor itself. if the asteroid was 15 kilometers there should be a hole somewhere in mexico anywhere from 105-150 kilometers wide
--ImageRemoved--

http://en.wikipedia.org/wiki/K%E2%80%93T_boundary

Re: LSAT's greatest controversy now settled

Posted: Sun Mar 07, 2010 3:39 pm
by Shrimps
Look up Chicxulub.

Chick Shoo Loob.

Re: LSAT's greatest controversy now settled

Posted: Sun Mar 07, 2010 3:42 pm
by chewdak
Chicxulub indeed, 180 km diameter

Image
Image

Re: LSAT's greatest controversy now settled

Posted: Sun Mar 07, 2010 3:42 pm
by BLi
yay, we're all talking the same thing!

Re: LSAT's greatest controversy now settled

Posted: Sun Mar 07, 2010 4:59 pm
by dynomite
From wikipedia:
The impact would have caused some of the largest megatsunamis in Earth's history, reaching thousands of feet high. A cloud of super-heated dust, ash and steam would have spread from the crater, as the impactor burrowed underground in less than a second.[25] Excavated material along with pieces of the impactor, ejected out of the atmosphere by the blast, would have been heated to incandescence upon re-entry, broiling the Earth's surface and possibly igniting global wildfires; meanwhile, enormous shock waves spawned global earthquakes and volcanic eruptions.[26] The emission of dust and particles could have covered the entire surface of the Earth for several years, possibly a decade, creating a harsh environment for living things to survive.
:shock:

Thanks for living through that, tiny woodland animal ancestor!

Re: LSAT's greatest controversy now settled

Posted: Sun Mar 07, 2010 5:05 pm
by BenJ
dynomite wrote:From wikipedia:
The impact would have caused some of the largest megatsunamis in Earth's history, reaching thousands of feet high. A cloud of super-heated dust, ash and steam would have spread from the crater, as the impactor burrowed underground in less than a second.[25] Excavated material along with pieces of the impactor, ejected out of the atmosphere by the blast, would have been heated to incandescence upon re-entry, broiling the Earth's surface and possibly igniting global wildfires; meanwhile, enormous shock waves spawned global earthquakes and volcanic eruptions.[26] The emission of dust and particles could have covered the entire surface of the Earth for several years, possibly a decade, creating a harsh environment for living things to survive.
:shock:

Thanks for living through that, tiny woodland animal ancestor!
The images of what North America would have looked like post-Chicxulub are pretty scary: basically, everything completely incinerated and entirely devoid of life. The rest of the world wouldn't have been hit quite as hard; the angle of the Chicxulub meteor strike means most of the hottest debris fanned across North America but missed the rest of the world.

Re: LSAT's greatest controversy now settled

Posted: Sun Mar 07, 2010 5:16 pm
by Shrimps
It's not the tsunamis and the fires that wiped out half the species. It is the 'nuclear winter' of debris and ash in the air blocking out much of the sunlight for the few years following the impact.

And the volcanic eruptions should not be excluded as the contributing cause of the extinction. A meteor of this side would've penetrated the Earth's crust and entered the magma, spiking the pressure in it and causing hundreds, if not thousands, of volcanoes to go off at the same time all over the planet.

In short, the temperatures on the planet must've crashed and stayed low for a few years until all the debris and dust and volcanic ash settled down and the sunshine could get to the ground again. The dinosaurs not so much burned as froze to death.

Look up http://en.wikipedia.org/wiki/Volcanic_winter and http://en.wikipedia.org/wiki/Year_Without_a_Summer

Re: LSAT's greatest controversy now settled

Posted: Sun Mar 07, 2010 5:30 pm
by dynomite
Shrimps wrote:It's not the tsunamis and the fires that wiped out half the species. It is the 'nuclear winter' of debris and ash in the air blocking out much of the sunlight for the few years following the impact.
Who's saying it didn't?
Shrimps wrote:And the volcanic eruptions should not be excluded as the contributing cause of the extinction.
Just because the bullet is what actually kills you doesn't mean the person who pulled the trigger is innocent.

Re: LSAT's greatest controversy now settled

Posted: Sun Mar 07, 2010 10:17 pm
by FreeGuy
I bet they'll still include this topic on the LSAT anyway. The LSAT-writers love it too much to take it off the exam.