Mammoth Comet Extinction...

[Guest Lambus]

.

.

.

.

.

.

.

.

.

.

[Turtle]

Comet May Have Doomed Mammoths

 

Hi Lambus. I ran across more info on the theory that an impact ended the ice age. Primary researcher I found is geo-chemist Dr. Luann Becker out of UC Santa Barbara.

 

ice age impact >> Ancient Meteor Blast May Have Caused Extinctions, Report UC Santa Barbara Scientists - Standard Newswire

 

...The scientific team visited over a dozen archaeological sites in North America where they found high concentrations of iridium, an element that is rare on Earth, and is almost exclusively associated with meteors. They found microspherules of glass-like carbon, which form at high temperatures and are thought to be a result of the impact blast. Also present were another type of impact tracer -- carbon molecules called fullerenes with gases trapped inside. ...

 

The technique Dr. Barker uses to isolate fullerenes created during impacts and then analyze gasses trapped is the newest tool in the box for positively ID'ing impacts. (others include shocked minerals and tektites)

:hyper: :)

[freeztar]

Interesting, Turtle.

What types of gasses do they look for to determine if it was a result of impact?

 

EDIT nevermind, I just read about the Helium in the other thread...

[TheFaithfulStone]

Interesting.

 

It doesn't help, I'm sure when those naked monkeys and their penchant for eating up all the tasty megafauna showed about a millennium or so later.

 

I can see how the double whammy would have made life difficult for the poor mammoths.

 

TFS

[Turtle]

Interesting.

 

It doesn't help, I'm sure when those naked monkeys and their penchant for eating up all the tasty megafauna showed about a millennium or so later.

 

I can see how the double whammy would have made life difficult for the poor mammoths.

 

TFS

 

The article implies humans & the megafauna were together already when the impact occured.

Wildfires across the continent would have resulted from the fiery impact, killing off the vegetation that was the food supply of many of the larger mammals like the woolly mammoths, causing them to go extinct. Since the Clovis people of North America hunted the mammoths as a major source of their food, they too were affected by the impact and their culture died out, explained Becker. ...

 

Keep in mind they are quoting Luann Becker, a geo-chemist; clearly she's not up on the latest anthropology of how & when & who populated the Americas. As I understand it, Clovis people moved elsewhere so it's a stretch to say they died out.

 

Interesting, Turtle.

What types of gasses do they look for to determine if it was a result of impact?

 

EDIT nevermind, I just read about the Helium in the other thread...

 

In the program Dr. Becker is featured in (discussed beginning post #59 here) she only refers to the Helium as "a type of Helium found only in outerspace." The reference in the other thread you read is just as vague. Chemistry is not my strong suit. :) :cup:

[freeztar]

In the program Dr. Becker is featured in (discussed beginning post #59 here) she only refers to the Helium as "a type of Helium found only in outerspace." The reference in the other thread you read is just as vague. Chemistry is not my strong suit. :note: :cup:

 

 

A quick look at the Wikipedia for Helium revealed this tasty tidbit:

There is only a trace amount of helium-3 on Earth, primarily present since the formation of the Earth, although some falls to Earth trapped in cosmic dust.[32] Trace amounts are also produced by the beta decay of tritium.[33] In stars, however, helium-3 is more abundant, a product of nuclear fusion. Extraplanetary material, such as lunar and asteroid regolith, have trace amounts of helium-3 from being bombarded by solar winds.

 

I suppose tektites will have to do for our on-the-ground explorations. :)

Now where did I put my moldavite? :hihi:

[HomoSapiens]

Most commonly i think it more like an ice age that may end of their rather than a comet?

[John L]

I'm a Physical anthropologist, and this sudden extinction event has always entrigued me, and I found humans suddenly hunting out several different species to be a bit outlandish. For many years now, the mystery of the vanishing fauna in post Pleistocene North America, has stumped paleontologists too. How did so many species suddenly disappear. And this ranges from the giant bison, ground sloth, dire bear, smilidon, North American horse, mammoth, and many others.

 

Theories have ranged from viruses to human interaction, to haitat change. Yet none of them have really been carried the day, as all have been a real stretch of imagination. The current explanations just did not add up.

 

This new theory does not rely upon any of the above causes. This one is celestial in nature, and is currently under close scrutiny. It's also a new theory, having just been raised in 2007, so it will be disputed for years to come. But it makes sense, just as mass extinctions in the past, have almost all been the result of celestial Impactors as well.

 

As an anthropologist, I find this spellbinding, because the implications are Huge. The prospect of random Impactors, capable of causing such disruption, adds to the threat of cyclical Inpactors which can cause even more damage and extinction rates. In other words, the longer we continue to keep all of our eggs in one single basket, the greater the odds that we too will be made extinct by some Impactor in the future.

 

New Clovis-Age Comet Impact Theory

 

Newswise — Two University of Oregon researchers are on a multi-institutional 26-member team proposing a startling new theory: that an extraterrestrial impact, possibly a comet, set off a 1,000-year-long cold spell and wiped out or fragmented the prehistoric Clovis culture and a variety of animal genera across North America almost 13,000 years ago.

 

Driving the theory is a carbon-rich layer of soil that has been found, but not definitively explained, at some 50 Clovis-age sites in North America that date to the onset of a cooling period known as the Younger Dryas Event. The sites include several on the Channel Islands off California where UO archaeologists Douglas J. Kennett and Jon M. Erlandson have conducted research.

 

 

For a more detailed and close examination of the theory, you can read more here: THE CLOVIS COMET Part I: Evidence for a Cosmic Collision 12,900 Years Ago

 

Here are a couple more schollarly publications on the topic.

 

Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling

 

Younger Dryas "black mats" and the Rancholabrean termination in North America, by C. Vance Haynes, Jr*

 

And keep in mind that an Impactor does not have to directly impact the surface of the planet to cause widespread destruction. I am referring to comets, which may come in and detonate in the atmosphere, expending most of it's kenetic energy, and heat, in the air.

 

I'll give you an example.

 

Here is something else, that is related to the topic, but first noticed in the southeast US. The Carolina Bays, by George A. Howard, 1997. I was not aware of Carolina Bays until just recently, but a cursory examination of them clearly shows them to be of celestial origin. I can't say that I agree with the concept of the bays being the result of cosmic 'burns', but they certainly look like an impactor that broke up and hit the planet in 'shotgun' form. I know that I would not wish to be within the area when this occured.

 

And that brings up another question. When did the Carolina Bays occur? Was it at the same time as the Clovis Comet? Or was it earlier? Or perhaps later? When it happened, there has been time for the topography to have leveled out.

 

It seems that the more we look at the planet, the more we realize that earth have been bombarded by celestial objects on a continual basis. I would think this to be far more frightening than the worry about global warming, wouldn't you?

 

 

Here is some more Carolina Bay information. To my thinking, this has got to be Impactor related. And the dating appears to be older than the Clovis Comet timeline. If you look at this Google Earth Shot, it is like looking at the effects of a shotgun shell being fired at a target, off to a slight angle. And these landmarks are found all over the North American continent, not just in the Carolinas. This points to some HEAVY bombardment from outer space. To acheive this, the Impactor would have had to break apart, waste most of it's energy in an atmospheric burst, and then the reminents striking the earth at many places, some greater than others.

 

And here is another picture. If you look closely, you can see that there are much older ovals, that have practically disappeared, and newer ones on top of the older ones. Clearly, this is not just a "one shot" deal, but occurs constantly, geologically speaking. Sort of makes one feel less than secure from the danger of being destroyed some day when you least expect it.

 

 

This abstract does a pretty good job of covering the details of the Bays and their implications.

 

A COMET AS THE BAY FORMING MECHANISM *

 

One other aspect peculiar to comets may be important to the genesis of the Carolina Bays. Because of the volatile content in a comet nucleus, a collision trajectory may not result in actual impact. Observations of meteors and fireballs indicate that some of these objects break up as they enter the Earth's atmosphere and sometimes explode in the air.

 

The 1908 Tunguska fall in Siberia is commonly regarded as the explosion of a very small comet nucleus. Hartmann (1973, p. 146) said that the explosion, estimated to be 1021 to 1023 ergs, knocked a man off his porch 38 miles away. Trees as much as nine miles from the impact site were felled radially outward by the shock wave, whereas trees at ground zero were merely denuded of their branches and left in growth position. Baldwin (1963, p. 37) added that trees in protected locations such as deep valleys remained standing and in some cases were still alive. According to Hartmann ( p. 146), by 1928 when trained observers first visited the site, they found the impact site to be pockmarked with a series of shallow, funnel-shaped depressions of variable width but not more than four or five meters in depth. No meteorites were discovered. Baldwin (1963, p. 37) noted that in 1928 the original forest vegetation was replaced with tundra except in the craters where swampy vegetation was already well established Hartmann (1973, pp. 146-147) summarized the evidence supporting a cometary origin for the 1908 fall:

 

1. The object evidently exploded in the air, since trees at "ground zero" stood upright but were stripped of branches. A loosely consolidated ice comet nucleus would be expected to volatilize and explode before it hit the ground.

 

2. The lack of meteorite fragments is consistent with our picture of a predominantly icy nucleus.

 

3. A 1961 expedition recovered soil samples that contained small spherules believed to be part of the object. The spherules would be consistent with the idea of an admixture of small grains of non-icy "dirt" in the dirty iceberg and their spherical shape could be the result of sudden melting during the explosion.

 

4. Observations of the motion of the object across the sky indicated that it was traveling toward the earth probably in retrograde motion at a very high velocity, perhaps 50 km/sec, which would be typical of a comet but not of ordinary meteorites. .

 

5. For weeks afterward, the night sky in Europe and Russia was anomalously bright. This may have been due in part to atmospheric interaction with tail and coma material (although the comet was too small to have been noticed prior to the collision, being on the order 101g to 1011g in mass instead of about 1018g, typical of observed comets).

 

Multiple shallow craters of variable widths, a climax vegetation destroyed except where topographically protected, the absence of meteoritic finds, a high velocity but low angle trajectory, plus a shock wave felt at least 38 miles and heard 620 miles from the impact site suggest a cometary explosion before actual impact. Hartmann stated that the Tunguska fall was a small comet nucleus. If such a singular event happened once, it could happen at least once more.

 

But if you think that this is less than worrisome, consider this. While these impactors break up in the atmosphere, there are many more that actually expend their energy upon striking the planet. There is no way of telling which is tme more prevelent, but there are still many, may earth strikes.

 

Also, it is slowly becoming clear that most major disruptions to human civilization were the direct result of celestial impacts, which disrupted the agricultural and climate conditions, resulting in collapses of civilizations. Even the "so called" Dark Ages are now being attributed to the aftermath of bombardment.

 

The Dark Ages : Were They Darker Than We Imagined?, By Greg Bryant. This is a very fascinating article. Here is some of it.

 

Mike Baillie is Professor of Palaeoecology at Queens University, Belfast, Northern Ireland. He is an authority on tree rings and their use in dating ancient events (every year, a tree adds a "ring" to its trunk as it grows - good years are represented by thick rings while bad years are represented by thin rings). He conducted a complete (and continuous) review of annual global tree growth patterns over the last 5,000 years and found that there were five major environmental shocks that were witnessed worldwide. These shocks were reflected in the ring widths being very thin. Wanting to know more, he turned to human historical records, and found that the years in question (between 2354 and 2345 BC, 1628 and 1623 BC, 1159 and 1141 BC, 208 and 204 BC, and AD 536 and 545) all corresponded with "dark ages" in civilisation.

 

Most people who are fairly knowledgable of astronomy, are familiar with the Torids, a meteor show(comet debris tail) that the earth goes through annually. Usually it is accompanied by a shower of debris, known to have come from the bread-up of the comet Encke, which had to have been one HUGE comet. But we do not cross it's main path often.

 

The calculations for the Taurids suggest that we pass through the core of the meteor stream approximately every 2,500 years - today, we are passing through the outer edges. The last two occasions when we passed through the core were in 2200 - 2000 BC and in AD 400 - 600. The epoch around AD 3000 looks like being a fun time too - the Y2K doomsayers can always say they just got the millennium wrong.

 

If you will note the dates above. The first timeline, 2200-2000 coincides with the end of the Bronze Age, and the 400-600 period that of the Dark Ages. Could this be just a coincidence? My guess is no.

 

"A large fraction of the objects on Earth-crossing orbits, of all dimensions, are the daughter products from the break-up of a giant comet some time during the past 100,000 years, dynamical studies suggesting around 20,000 years as likely. All that is suggested here is a break-up similar to that undergone by P/Shoemaker-Levy 9 in 1992, except by a comet at least 100 kilometres across and in an orbit crossing from Jupiter to the Earth.

 

The core of the complex...evolves to have a node near 1 AU every millennium or so, at which time the Earth is bombarded by many [large] objects in episodes at certain times of year. It is these events that dominate the hazard to humankind. Such an episode would last for a century or two."

 

We have a pretty good idea that there are some HUGE comets out there in the Ort Cloud, and they are mainly long term comets, so we cannot project their danger until they enter the inner solar system, and are affected by Jupiter's gravitational pull, which will alter it's orbital path. If a comet can be 100 km or more, the danger presented it unimaginable.

 

Also, remember, asteroids are made up of the same material as that of comets. All are material from the original forming of the solar system. The only difference is that comets still retain a larger amount of volatile, frozen gasses, that have not vented out. But they still have large amounts of solid components. And most inner orbital asteroids are nothing more than comets that have already broken up and assumed more stable orbits.

 

Is Global Warming worth worrying about? Should we be worried about a warmer planet? Or should be be Really concerned about some huge object dropping in, from outer space, and obliterating civilization, on moment's notice? I'll let you decide that one, I've already made up my mind, a long time ago. :wink: [/size]

[Turtle]

This is a fascinating new set of developments!!!!! I better let the folks who put on the NOVA show I just watched, speak for themselves. Not sure if the program is available yet to view online, but check your local TV listings at their site as it may rerun this weekend. :lightning Wow this is excititng!!! Anyone else catch the program? Enquiring minds want to know.

 

NOVA | Last Extinction | PBS

 

Teaser, or, look Ma, no crater:

Modeling a Comet Airburst

In this video clip, see why an explosion three miles above Earth would act like a white-hot tornado on the surface.