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Earth Science & Geology News
#21
The two scientists in my post just above yours claim that they really don't know what could be causing this 27 MY extinction clockwork, but they claim a 99% surety of the time table. And maybe there really isn't a Nemesis, or galactic plane causing this. But obviously something is doing it, and thinking that plate tectonics works on a strict timetable is perhaps a bit out of the picture. It has to be something celestial that is causing this.

This theory has been around since 1983, and has had thirty years of fine tuning, which is what this paper has led to. You can read the position paper here: Nemesis Reconsidered.

Perhaps the Oort cloud is not out as far as science thinks. And perhaps there is a large body that became captured early on, that has a strange orbit is not in line with the rest of the system. The object wouldn't have to collide with all those comets out there, but just might affect them enough to cause a large number to lose their shaky orbit and start falling inward. And if they set up a new pattern with the sun, they could keep falling inward, like Haley's Comet, until they strike something, or break up.

This entire thing could play out for a long time after the object had shifted its orbit. In some cases, several comets could hit the planet, and in others, perhaps just one, causing less damage than others. That could be why some mass extinctions were huge, and some were not so huge.

But the shock from these objects striking the surface would set up ripples that would immediately cause pent up tectonic tension to be releases all together. And more than one strike would do this over again with each strike.
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#22
Quote: But obviously something is doing it, and thinking that plate tectonics works on a strict timetable is perhaps a bit out of the picture.

Not at all. Firstly, plate tectonics may be affected by the cycle (in other words, plate tectonics is just a conduit).
And secondly, there is also the possibility that the largest extinction events have a different mechanism than the smaller events on the cycle.

Incidentally, take a careful look at the chart you posted and mentally delete the peaks.... then you should see that the overall trend is toward milder extinctions! An explanation is needed.
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#23
(03-22-2013, 04:26 PM)mv Wrote: Incidentally, take a careful look at the chart you posted and mentally delete the peaks.... then you should see that the overall trend is toward milder extinctions! An explanation is needed.

Most likely due to being hit with less, or smaller, comets. The big extinction events would have occurred due to much larger impactors, or more in number.

The planet is a very small, and moving, target. Almost every comet would miss us, or impact somewhere else, or fly off into the galaxy. Very few, if any, would hit us. But some cycles would be far worse than others, due to the frequency, or intensity, of impacts.

And again, mass extinctions due to volcanic activity alone, would not be keeping to a time clock, unless awakened by another event that triggered it. Can you think of any other regular triggered timetable other than a celestial impact?
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#24
(03-22-2013, 05:12 PM)John L Wrote:
(03-22-2013, 04:26 PM)mv Wrote: Incidentally, take a careful look at the chart you posted and mentally delete the peaks.... then you should see that the overall trend is toward milder extinctions! An explanation is needed.

Most likely due to being hit with less, or smaller, comets. The big extinction events would have occurred due to much larger impactors, or more in number.

I asked a different question: why the peaks are getting smaller. (why some peaks are huge and some small is ok... this is random process... but there is also a visible trend. Most likely it is a deficiency of their methodology, but it still needs to be understood.)


Quote:And again, mass extinctions due to volcanic activity alone, would not be keeping to a time clock, unless awakened by another event that triggered it. Can you think of any other regular triggered timetable other than a celestial impact?

I'll give you two:
1. Gravitational disturbance due to celestial non-impact events (passing of Nemesis or crossing the galactic plane are both possibilities).
2. Some kind of internal cycle deep inside the Earth. (We know that there are several cycles of Sun's activity ... given that there are some nuclear processes going inside Earth, there may be some cycles affiliated with them too). Actually, I'd think there are such cycles for sure, they are just very hard to detect.
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#25
(03-22-2013, 05:54 PM)mv Wrote:
(03-22-2013, 05:12 PM)John L Wrote:
(03-22-2013, 04:26 PM)mv Wrote: Incidentally, take a careful look at the chart you posted and mentally delete the peaks.... then you should see that the overall trend is toward milder extinctions! An explanation is needed.

Most likely due to being hit with less, or smaller, comets. The big extinction events would have occurred due to much larger impactors, or more in number.

I asked a different question: why the peaks are getting smaller. (why some peaks are huge and some small is ok... this is random process... but there is also a visible trend. Most likely it is a deficiency of their methodology, but it still needs to be understood.)

Oh, I now see what you are getting at. First impression is that as the solar system gets older, there are less available comets in the Oort cloud to be shaken loose? Perhaps certain orbits have changed a bit? I'm not really sure. But it makes sense that the further back in time, the more objects are flying around the system than today.

That would be interesting to know, but I'm not sure how that could be determined with certainty.


Quote:
Quote:And again, mass extinctions due to volcanic activity alone, would not be keeping to a time clock, unless awakened by another event that triggered it. Can you think of any other regular triggered timetable other than a celestial impact?

I'll give you two:
1. Gravitational disturbance due to celestial non-impact events (passing of Nemesis or crossing the galactic plane are both possibilities).
2. Some kind of internal cycle deep inside the Earth. (We know that there are several cycles of Sun's activity ... given that there are some nuclear processes going inside Earth, there may be some cycles affiliated with them too). Actually, I'd think there are such cycles for sure, they are just very hard to detect.

The problem with the second hypothesis, unlike the first one, is that establishing a certain rhythm that would go by a strict clock. And while there may be cycles, how can the timing be precise? With the first hypothesis, even timing makes sense.

Again, exact timing between intervals is the key. If the times don't jibe, then the theory doesn't hold up.
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#26
Quote: First impression is that as the solar system gets older, there are less available comets in the Oort cloud to be shaken loose?
Possible (if impactors matter, which I doubt). Another possibility (and the first one to consider) is that there is a systematic error in the paper connected to having fewer older fossils than newer ones and not adjusting properly; alternatively, it is possible that the error is related to the increase of vertebrate species over time (vertebrates leave better fossils). One should look at the original papers carefully and check if the authors even noticed the trend and if they did whether they did some dangerous adjustments.

Now, if the trend is real, then there may be other reasons for it not connected to thinning of the Oort cloud... for instance, it may be that evolution leads to more adaptable (and thus more likely to survive) lifeforms over long time.

This is quite interesting, btw.

Between #1 and #2, I favor #1. But timing of nuclear process may be quite precise and lead to cycles too... given how little we know about what is happening in the core, I would not dismiss this.
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#27
Yeah, this entire thing is indeed interesting, to say the least. I've been pretty much fixated on this field ever since the Alvarez family(father and son) first discovered, and pegged, that band of iridium at the K/T boundary in the late 70s. Between them and Shoemaker, I've spent more time studying this mass extinction concept and Impactor theory more than even the global warming one.

My biggest complaint with the way people keep referring to the Impactors is that they are always asteroids in everyone's eyes. This makes no sense. All the "Big Ones" were almost certainly comets, which is where almost all asteroids originated in the first place. Its as though asteroids are easier to pronounce, so they keep using that word. I guess most people view comets as some distant fluffy, and pretty little things, that work in the background, and then occasionally some mean old asteroid comes along and ruins everyone's lives.

Where do people come up with some of this stuff? That's why I use "Impactor" instead, because it incorporates every object that can come in and reek havoc. S5
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#28
(03-23-2013, 01:47 AM)John L Wrote: My biggest complaint with the way people keep referring to the Impactors is that they are always asteroids in everyone's eyes.

Then you should be very pleased with what came out of BBC just now.

I however remain skeptical of this one being an extinction trigger. It seems that we have two volcanic areas (Siberia and India) to account for the two largest extinctions (regardless of these two sites possibly also being Impact sites). Mexico is an extra and a small one too...

Well, at least we are slowly learning something...
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#29
And for collection, here is another "Volcano theory" article: http://articles.latimes.com/2013/mar/21/...s-20130322

Not the same.

Quote:New findings support the theory that a massive volcanic event tore apart Pangea and dramatically changed Earth's climate, ushering in the biggest biological shift in the planet's history.

"event tore apart Pangea" ===> Huh?

one should probably read the actual paper to see if this claim is in there...
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#30
(03-23-2013, 02:07 AM)mv Wrote:
(03-23-2013, 01:47 AM)John L Wrote: My biggest complaint with the way people keep referring to the Impactors is that they are always asteroids in everyone's eyes.

Then you should be very pleased with what came out of BBC just now.

I however remain skeptical of this one being an extinction trigger. It seems that we have two volcanic areas (Siberia and India) to account for the two largest extinctions (regardless of these two sites possibly also being Impact sites). Mexico is an extra and a small one too...

Well, at least we are slowly learning something...

It just tends to validate my thinking:

Quote:For this smaller space rock to have produced a 180km-wide crater, it must have been travelling relatively quickly. The team found that a long-period comet fitted the bill much better than other possible candidates.

Coming from the Oort Cloud is exactly what they are saying. And the Oort cloud is where something big tends to happen every 27 MYs or so.

My guess is that those scientists who don't subscribe to the precise periodic mass extinction theory are using asteroids because they can come in any time and not have a time table. And those who do subscribe to the theory know that only comets are the culprits. I'll rest my hat on the later group, because its the most logical way of explaining precise periods.

And as for the comet issue, comets tend to travel at about double the speed of an asteroid, because they come in from way out in the solar system and have gravity to slingshot them around the sun. They generate great momentum.

Asteroids have generally lost that speed as they broke off from older comets and are subject to other gravitational tugging and pulling from other bodies, causing them to slow down. So when they enter the atmosphere they have much less kinetic energy to dump.

Anyway, great article. As for your 'extinction trigger', someone will eventually set up an experiment showing how the ripple effect of energy from an impact site can generate other seismic events. I don't know of any scientific experiment on this as of yet.

If you just take a tsunami, and watch the wave effect, when it comes to an island, the energy will travel around the island, and when the two converging waves collide, the result is frequently a wave that is equal to, or greater than, the two combined. The same thing happens to the planet, which really has only a thin solid outer crust. The molten inner portion will transfer the rippled energy along, causing the crust to buckle on the other side of the globe.
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#31
Incidentally Michael, here is one more thing about this article, and position paper, you may also wish to consider. Perhaps there is also an agenda present that is being slipped in and you may not even have caught it. Anthony Watts did, and here is what he has to say about it. Note his comment at the bottom of the article.

Quote:I can play this game, using their paragraph:

From the National Science Foundation, another bit of Speculative Science™ note the caveat in bold, which is all they need for a headline that screams certainty:

Quote:This sudden release of gases into the atmosphere may have created intense global warming, and acidification of the oceans, which ultimately killed off thousands of plant and animal species.

See below for the alternate scenario based on the same press release.
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At the bottom of the article.

Change a couple of words, and we have a whole new plausible scenario:

Quote:This sudden release of ash, soot, and stratospheric aerosols (like SO2) into the atmosphere may have created intense global cooling, due to blocked sunlight, which ultimately killed off thousands of plant and animal species.

Its obvious that the writers of this position paper are AGW diehards, or Kooks, depending on the degree of your opposition. I wonder how much they will receive in grant monies for the purpose of studying the amount of intense 'Global Warming' that they think may have occurred way back then? Had they stated what Anthony Watts did, its for certain they would never have received any grant money, because global cooling is not a hot commodity..............yet. S5
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#32
Yeah, I noticed this yesterday.. S4

Quote:Its obvious that the writers of this position paper are AGW diehards, or Kooks

Not obvious, Whores is another applicable diagnosis. And it says something sad about the state of science when AGW whoring spreads to other areas like this.
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#33
Let me rephrase it then. It is 'obvious' to some, such as myself,.................................... How's that?
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#34
I do think they are merely whores, sorry! (but yes, the precise psychiatric diagnosis is never easy). S13
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#35
Now the CIA is getting into studying how to control the planet's weather.

CIA backs $630,000 study into how to control global weather through geoengineering

I realize the money is must a drop in the bucket of wasted funds, but its still a total waste of resources.
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#36
Antarctica is about to have its first sunrise, in preparation for the coming summer. A sunrise is almost there, as shown by this picture.

[Image: Winter_at_Concordia_node_full_image.jpg]
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#37
Well, Lookie Here: A Massive Volcano that rivals the biggest in the solar system. And its right here on earth, but underwater. Just imagine what is waiting under the oceans, for us to discover? And just think of the excellent paying job openings for marine geologists? S5
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#38
Scientists have finally discovered where all the Noah's Flood water originated. Creationists will be rejoicing. S22
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#39
That is what creationists have postulated from the beginning. The Bible does not say all the water came from the sky. It says that in addition to the rain, "...on that day all the fountains of the great deep were broken up, and the windows of heaven were opened."

The Creator, who inspired Genesis, of course knew that there was a "great deep."
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#40
That study reports that a zone of the interior has a moisture content of 1.5%, and already under great heat and pressure. That isn't water. 40 days and nights of dampness?
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