Just spotted this on the web. It claims that there is some new evidence which suggests a space rock didn't knock off almost all species (and that it was huge volcanic eruptions) 65 million years ago...

Yahoo News Article .

Seanie.

Another case of scientists who don't connect the dots, or just publicity hounds? It seems to me that they haven't pinned down the timing sufficiently to support any sweeping statements, certainly not the ones that journalists love - which is why these things are better published in scientific journals than the mass media.

My immediate reaction is to ask whether the scientists can show that the Deccan eruptions happened before, at the same time as or after the Chicxulub impact? It stands to reason that a major surface impact would create shockwaves in the magma below that might have a significant effect on other parts of the planet. If the Deccan eruptions occurred at the same time as the impact or afterward then they may have been one of its consequences. It would make sense and the answer would be worth knowing.

The Yukatan strike occured DURING the Deccan eruptions.

There is a real possibility that two asteriods hid the earth.

A very large one first might have punched a hole right through the earth's crust into the molten mantle, releasing thousands of cubic miles of magma.(And destroying the strike evidence.)

A smaller one on a similar path hit Yukutan later.

Lots of arterouds follow similar paths because they suffer similar disruptions by Jupiter.

Peter.

Hi Seanie
Since what has been termed the “Cambrian Explosion” (~540 Million years ago, [explosion in terms of many diverse multi-cellular life forms appearing suddenly, i.e., within ~30 million years of that geological time period as shown in the fossil record]) evidence thus so far known shows that there have been five major mass extinctions on Earth with various hypothesised causes and complications attributable based on current research, meteor/comet impacts been cited for one or more mass extinctions.
What’s also interesting for me as an amateur astronomer is the possibility of the dangers of what lies out there in space in the form of black holes, Nova / Supernova, Neutron stars, planets that may have been ejecting from their solar systems due to various cataclysmic factors and are now akin to a cosmic billiard ball. It takes the Solar System about 225–250 million years to complete one orbit and so it is thought to have completed about 20–25 orbits during its lifetime, the sun also bobs in and out of the galactic plane, there is the possibility of our solar system perhaps encountering any of these dangers, but then again space is big, very very big, perhaps as they like to say on the discovery channel, “It’s not a matter of if, but a matter of when”.
However I am more concerned with the sixth mass extinction happening already in the form of human overpopulation, deforestation, accelerated extinction of plants and animals, pollution of the biosphere, nuclear, biological, chemical and EM weapons.
en.wikipedia.org/wiki/Cambrian_explosion
www.space.com/scienceastronomy/planetear..._sidebar_000907.html
www.actionbioscience.org/newfrontiers/eldredge2.html

Clear skies
Mike

By the way,

The famous Iridium Layer which is the smoking gun of the Yukatan impact goes right through a Deccen lava layer.

This proves that that the Mexican impact occured during the Deccan eruptions.

(This story is an ancient one by the way. Nothing new about this discussion.)


Peter.

The Yukatan strike occured DURING the Deccan eruptions.

There is a real possibility that two asteriods hid the earth.

A very large one first might have punched a hole right through the earth's crust into the molten mantle, releasing thousands of cubic miles of magma.(And destroying the strike evidence.)

A smaller one on a similar path hit Yukutan later.

Lots of arterouds follow similar paths because they suffer similar disruptions by Jupiter.

Peter.

Good point. A series of hits over a long time span could do it.

Volcanism around the same time created the Siberian traps, the combination of the Deccan and Siberian traps along with one or more asteroid impacts would mean that Dino and his friends had no chance.

Page 17 of this month's(Dec.) Sky and telescope makes the following point on this subject:

"A titanic asteroid collision out beyond Mars some 160 million years ago......produced the 3,000 known members of the Baptistina family of asteroids...caused a prolonged asteroid shower peaking from 100 to 50 million years ago.....Chronium in the Chicxulub debris on Earth strengthens the Baptistina connection."

There could well have been a whole shower of them.

Large swathes of Siberia and India were molten lakes around that time.

Just volcanism?

Peter.

By the way,

The famous Iridium Layer which is the smoking gun of the Yukatan impact goes right through a Deccen lava layer.

This proves that that the Mexican impact occured during the Deccan eruptions.

(This story is an ancient one by the way. Nothing new about this discussion.)


Peter.

filebox.vt.edu/artsci/geology/mclean/Din.../pages/studentv.html

I wont go into the Permian extinction which put Earth into a Mars like state.

The Deccan Trapps may well have aggrivated the situation but where did the Iridium come from? And not alone that but Luis Alverez father Walter I believe- a nuclear chemist- also got some results with Rhenium in the K-T bounary.

Iridium and Rhenium are extra terrestrial. If they were somewhere deep inside the Earth then they should show up in the Deccan strata. AS far as I know they don't!

www.springerlink.com/content/pk22765973212w45/

It has been suggested that the eruption of the Deccan Trapps has contributed to the events of the Cretaceous-Tertiary transition as a possible cause of Iridium enrichment and/or other physicochemical disturbances. However, no precise chronological framework was available for the emplacement of these Trapps, which form one of the largest known occurrences of continental basalt flows. A joint Indian-French project, still under way, is providing more accurate informations about the chronology of the Deccan Trapps and its possible implications for Cretaceous-Tertiary boundary events.
[end quote]

Okay okay I know it is over twenty years ago! For "I believe" read "further research is necessary"
But who will fund it?

For such a critique read: filebox.vt.edu/artsci/geology/mclean/Din...n/pages/ltrkerr.html

And what about www.lpi.usra.edu/meetings/gold99/pdf/7063.pdf

Well what about an extraterrestrial impact when the volcano was active?
Or as you might say at a conference "na na nana na. Correlation isnt causailty."

There is also the as yet unproven "crater chain" theory. So where is the beef? subducted? Under the atlantic? Your guess is as good as mine but there are no known co incident craters to add to Chicxulub.
Pope and Ocampo are the guys for that stuff I believe.

Oh and the two mathematicians spring to ming. Odd that maths guys got interested in paelentology - Raup and Sepskoski. great stuff. Added rigour to geology! (as if rocks can get stiffer).

Here is the original:

Raup, D. M. & Sepkoski, J. J. Jr. 1984. Periodicity of extinctions in the geologic past. Proceedings of the National Academy of Sciences USA, 81, 801–5.
www.pnas.org/cgi/reprint/81/3/801

By the way,

The famous Iridium Layer which is the smoking gun of the Yukatan impact goes right through a Deccen lava layer.

This proves that that the Mexican impact occured during the Deccan eruptions.

Peter. Have you any citation for this claim?

By the way two related points.

The famous "Burgess shale" is one of very few sites around the world which is packed with fossils. there is another in a dover like cliff in Denmark.
Stevns Klint

In fact I believe a Dane preceeded Alvarez in the discovery and had already thought of and got a spanish nuclear physicish to start looking for minute concentrations of Iridium. But though he had the results BEFORE he actually only got it published AFTER Alvarez. alvarez got the nobel prize.

I think this is the alvarez paper. His Da (who won a different Noble prize) gave him a hand so TWO Alvarez's are cited Walter and Luis:

Alvarez, L. W., W. Alvarez, et al. (1980). "Extraterrestrial Cause For the Cretaceous-Tertiary Extinction - Experimental Results and Theoretical Interpretation." Science 208(4448): 1095-1108.

i think the Dane published in Nature only three months later! Mind you alvarez credited him years later with the discovery in "T Rex and the Crater of Doom"

Second is the idea of a dark star or red dwarf orbiting out in the outher solar System as a mechanism for the periodicity of the extraterrestrial impacts. Richard Muller a physist was appraoched by Alvarez in a "chat" on day in his office (the both worked at the same university Berkeley - incidentally named for the Irish Bishop). Alverez showed Muller the Raup and Sepskowsky graph asking what could cause periodicity:

muller.lbl.gov/papers/explot.GIF

Arrows every 26 Million years.

IIRC Muller questioned the results and suggested Rhenium but alverez had already done that unknown to Muller and got similar results.

straight away Muller suggested a dark star! not alone that but he got out a pen and worked out the orbit on a piece of paper!

More about it here:
muller.lbl.gov/pages/lbl-nem.htm
For other theories on the periodicity (and for some very good science fantasy and science fiction) see :
en.wikipedia.org/wiki/Nemesis_(star)
muller.lbl.gov/

By the way,

The famous Iridium Layer which is the smoking gun of the Yukatan impact goes right through a Deccen lava layer.

This proves that that the Mexican impact occured during the Deccan eruptions.

Peter. Have you any citation for this claim?

By the way two related points.

The famous "Burgess shale"

I forgot my first point and went off topic!

Point being. there are three to five sites IIRC. And the Burgess on (discovered by accudent when Burgess was out horse riding) is only about the size of a house roof!

Second is the idea of a dark star or red dwarf orbiting out in the outher solar System as a mechanism for the periodicity of the extraterrestrial impacts. Richard Muller a physist was appraoched by Alvarez in a "chat" on day in his office (the both worked at the same university Berkeley - incidentally named for the Irish Bishop). Alverez showed Muller the Raup and Sepskowsky graph asking what could cause periodicity:

muller.lbl.gov/papers/explot.GIF

Arrows every 26 Million years.

IIRC Muller questioned the results and suggested Rhenium but alverez had already done that unknown to Muller and got similar results.

straight away Muller suggested a dark star! not alone that but he got out a pen and worked out the orbit on a piece of paper!

Nemesis is literally a rather far-out theory. There's a good balanced article about it on space.com. The ending in particular is important to bear in mind when talking about this:

Whether or not he finds evidence for Nemesis in Moon dust, it's clear that Muller won't stop looking. He is a man of enduring confidence. But he is also a remarkably conservative scientist, quick as anyone to point out that there is no proof until there is proof.

"I'm realistic," he said. "I may be wrong."

And he recognizes that if the Death Star is not found, the whole idea could become a real Nemesis for the big thinker who dreamed it up.

The full article is here: www.space.com/scienceastronomy/solarsyst...emesis_010320-1.html

Bart.

Nemesis is literally a rather far-out theory.

LOL. Pun intended?

Whether or not he finds evidence for Nemesis in Moon dust, it's clear that Muller won't stop looking. He is a man of enduring confidence. But he is also a remarkably conservative scientist, quick as anyone to point out that there is no proof until there is proof.

"I'm realistic," he said. "I may be wrong."

Reality is what is still there when you stop believing in it.
Mind you I thought it was faily much debunked. But it appears like some Planetary scientists when quizzed on ALH 87001 and the possibility of life on Mars said "Absence of evidence is not evidence of absence".
Ironically, this is supporting of a point I was making elsewhere about science not having to be based on fact and evidence. It is fairly likely Nemsis does not exist, in which case there will never be any scientific evidence to support it. However I still believe it is a creative concept and good science!

The full article is here:
Bart.

thanks for that Ill read it if and when I get time.

Reality is what is still there when you stop believing in it.
Mind you I thought it was faily much debunked. But it appears like some Planetary scientists when quizzed on ALH 87001 and the possibility of life on Mars said "Absence of evidence is not evidence of absence".
Ironically, this is supporting of a point I was making elsewhere about science not having to be based on fact and evidence. It is fairly likely Nemsis does not exist, in which case there will never be any scientific evidence to support it. However I still believe it is a creative concept and good science!

Absence of evidence is indeed not evidence of absence. That's a fundamental principle of science.

Nemesis is a hypothesis. Nothing more. Science does NOT say that it is true. It also does not state that it is NOT true. Because, until there is evidence, science does not accept that Nemesis is real. Until someone goes out and actually starts making some observations to test the hypothesis science doesn't have anything to say on Nemesis apart from "that's an interesting idea".

Dreaming up new ideas in an integral part of science. Without that creative and imaginative part science would stagnate. However, that does not make science faith based.

Bart.

Absence of evidence is indeed not evidence of absence. That's a fundamental principle of science.

But apparently not of Politics ! For example I am not aware of evidence of WMD in Iraq

Nemesis is a hypothesis. Nothing more.

Are not "black holes," "wormholes," "parallel universes" "dark matter" ?

Indeed even everyday concepts like "Atoms" or "biological cells" can be put under the microscope

Science does NOT say that it is true. It also does not state that it is NOT true.

As i have stated before I have a problem about saying "science" says anything. Usually "scientists" say things. I am not being facietious. the point is that iof one appeals to an objective entity called "science" then 1. one is subscribing to a particular mindset and philosophy of science and
2. How can a body of knowledge "say" things. Surely it is only re itteratng what PEOPLE put into it in the first place?

Because, until there is evidence, science does not accept that Nemesis is real.

Scientists accepted the CMB as real and Relativity in the absence of evidence maybe because the theory was so tidy. True it hasn't been CONFIRMED. but that does notmake the theory real science even iof the object of that theory does not exist!

Until someone goes out and actually starts making some observations to test the hypothesis science doesn't have anything to say on Nemesis apart from "that's an interesting idea".

But IIRC people HAVE tested this and have not confirmed Nemsis. that does not mean it is NOT real either.

Dreaming up new ideas in an integral part of science. Without that creative and imaginative part science would stagnate. However, that does not make science faith based.

Yes but it does mean that some science is done BECAUSE scientists have a belief in something without any evidence for that belief. Indeed the theory may not even be testable or confirmable for hundreds of years if ever. Which brings nme back to worm holes and Occakms Razor. what is the point in discussing other parallel universes if we can never communicate with or through them? Maybe we are better sspending money looking for non - existant stars?

*Moved to the Cosmology & Physics forum*

Scientists accepted the CMB as real and Relativity in the absence of evidence maybe because the theory was so tidy. True it hasn't been CONFIRMED. but that does notmake the theory real science even iof the object of that theory does not exist!

Really? Relativity was accepted in the absence of evidence? Which Relativity, special or general?

This better not be the standard claim that scientists accepted General Relativity after the solar eclipse of 1919, because journal articles from that period will show they didn't. General Relativity wasn't truly accepted until the mid 50s.
Unless you are talking about the acceptance in the mid 50s being unjustified.

what is the point in discussing other parallel universes if we can never communicate with or through them?

Nobody researches parallel universes. The closest anybody comes is Deutsch and even then he still isn't researching them.