This seems to be our week for new material on the comet impact event of 13,000 years ago. Yesterday we discussed the emptying of Lake Agassiz
This interpretation of the impact event that is associated with what I have styled the Pleistocene nonconformity comes up short but still builds the literature. The event itself was only recognized several years ago. It is still way too early for researchers to accept that the crust itself shifted at the time actually ending the Ice Age.
I do not know were scientists come up with the idea that the improbability of an event is an argument against it. That is errant nonsense. It is merely a sound reason to not be personally concerned at all today. In the meantime we have gobs of evidence that an event took place.
As I have posted the comet struck the northern Ice Cap near the then location of the pole. Yesterday’s post on Lake Agassiz suggest the impact flooded an extant Lake Agassiz
We also see the wildfire theory been repeated. I made the mistake of accepting that idea at first also. Had it any basis in natural processes there would be a thick layer of soot on the ground because of the natural forest fire cycle.
What happened is that all that soot is cometary dust which we now understand consists of mostly elemental carbon. This was no mild event. This also clarifies the expansion of a comet as it approaches the sun. The carbon charges up and is forced apart by electrostatic pressure.
I am pleased to see this advent of much more substantial evidence than I had available to make my conjectures. It is often necessary in science to develop a conjecture and then wait for evidence to catch up.
I would like to see folks debating the merits of the crustal shift conjecture simply because masses of evidence exists that simply needs reinterpretation. So far it is only my eyeballs and few others. Thousands of eyeballs would quickly flood us with plenty of supporting data. It certainly is there everywhere I found it possible to look.
With or without Lake Agassiz instantly flooding the Atlantic, the crustal shift triggered the melting of the ice cap that flooded fresh water into the Atlantic for a couple of thousands of years. I suspect the effect of Lake Agassiz
The day the Earth froze: An hour-long storm started a mini ice age, say scientists
Last updated at 8:48 AM on 02nd April 2010
An hour-long hailstorm from space bombarded the Earth 13,000 years ago - plunging the planet into a mini-ice age, scientists claimed today.
The catastrophe was caused by a disintegrating comet and saw the planet sprayed by thousands of frozen boulders made of ice and dust.
The collisions wiped out huge numbers of animal species all over the world, disrupted the lives of our stone age ancestors and triggered a freeze that lasted more than 1,000 years.
New theory: An hour-long hailstorm from space bombarded the Earth 13,000 years ago - plunging the planet into a mini-ice age
The theory is the brainchild of Professor Bill Napier, from Cardiff University
Scientists have long been puzzled by what caused a sudden cooling of up to 8C (14F) just as the Earth was warming up at the end of the last ice age.
The change in climate caused retreating glaciers to advance once again, and coincided with the extinction of 35 families of North American mammals.
Some geologists have argued that the world was hit by a giant asteroid - a smaller version of one which wiped out the dinosaurs 65million years ago.
The collision left behind tell tale traces in the rocks - including a black 'mat' of soot an inch thick thought to have been created by continental wide wildfires.
Microscopic 'nanodiamonds' created in massive shocks and only found in meteorites or impact craters have also been discovered dating back to the disaster.
Wiped out: The woolly mammoth
These findings have led to claims that a 2.5mile long comet or asteroid smashed into the ice sheet covering what is now Canada
But other scientists say the chances of the Earth being struck by such a large object only 13,000 years ago are one thousand to one against. And they say a single impact cannot explain such widespread fires.
Professor Napier's theory suggests the devastation took place when the Earth strayed into a dense trail of fragments shed by a large comet.
Thousands of chunks of material from the comet would have rained down on Earth, each one releasing the energy of a one megaton nuclear bomb.
The impacts would have filled the atmosphere with smoke and soot and blotting out the Sun.
Prof Napier says a comet swooped into the inner solar system between 20,000 and 30,000 years ago and has been breaking apart ever since.
'A large comet has been disintegrating in the near-Earth environment for the past 20,000 to 30,000 years and running into thousands of fragments from this comet is a much more likely event than a single collision,' said Professor Napier.
His model, published in the journal Monthly Notices of the Royal Astronomical Society, suggests that the 'hailstorm' would have only lasted about an hour.
It would have caused thousands of impacts, generating global fires and depositing nanodiamonds at the 'extinction boundary' marking the point in time when many species died out.
One recent impact that may have come from the comet is known as the Tagish Lake
The object fell on Yukon Territory in Canada
Read more:
No comments:
Post a Comment