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Antarctic Craters Reveal Asteroid Strike
dhuff writes "Scientists using satellites have mapped huge craters under the Antarctic ice sheet caused by an asteroid as big as the one believed to have wiped out the dinosaurs 65m years ago."
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It could have been an explosion from several adolescent Predators when being overtaken by thousands of Aliens?
Well....
;)
The compass industry will go South
If they find pyramids under there, stay away from them.
I don't dispute Hans' rigor in studying the issue, but how can the correlation of the impact and the magnetic field reversing lead to the conclusion the impact caused the reversal?
And why even compare this 780K yr old impact to what might've done the dinosaurs in 65m yrs ago? It just would confuse people with poor reading skills (*cough* slashdot readers) and lead them to associate this 780K yr old impact with the extinction of the dinasaurs.
Also, the article attemps to explain why the 65m yr old impact would've caused climactic change whereas the 780k yr old impact would not -- I didn't quite understand their argument of why the older impact caused dust clouds leading to extinction while the newer impact did not -- was it because of the composition of ice vs rock?
"Does the magnetic field being reversed actually affect anything important?"
/.), Earth's magnetic field has weakened 10-15% since we started measuring 150 years ago. Maybe our grandkids will have to wear lead undies.
It doesn't matter what direction the field points, what matters is that there is a magnetic field around the Earth. During the time it takes for the field to flip, the field becomes very weak. That causes two problems. Some animals use the magnetic field for navigation. More importantly, the field is a shield protecting us from cosmic high energy particles. According to a story in the NY Times (covered on
-B
That's 24 days ago.
The dinosaurs were wiped out on July 28 2004?
a lot of people believe that the 65m impact was centered over land NOT covered by ice and snow, as in the central point in which all current continents used to be connected (pangea).
That impact would have crushed mountains and created enormous amounts of dust from them. The 780k impact hit a huge block of ice and snow, i.e. no dust to scatter in the first place. I really doubt it would have affected any land life at all, antarctica being so far from land inhabited by anything more than penguins and stuff. Ocean life probably got pretty roughed up at least close to the impact.
The Earths Magnetic field keeps all kind of nasty radiation from hitting the surface.
So it's always been a bit of a puzzle why there's no correllation between magnetic reversals (where the magnetic field weakens, fades, then reappears with swapped poles) and mass extinctions.
After all, one would think that floods of radiation washing across the Earths surface would be unhealthy, no?
But now it appears that when the magnetic field weakens, the solar wind induces a magnetic field in the ionosphere that's pretty much as effective at stopping high energy particles and cosmic rays as is the original field.
Here's an article about it in New Scientist from a few months ago.
New Scientist