Meteor Seen as Causing Extinctions on Earth 67
An anonymous reader writes "From the NY Times (I think you may have to register): About three dozen minuscule shards of rock unearthed in Antarctica may be the fragments of a meteor that killed most life on Earth 250 million years ago, scientists are reporting today. These rocks have yielded soccer-ball-shaped molecules known as buckyballs containing extraterrestrial gases, as well as grains of quartz with fractures that indicate a tremendous shock. The extinction 250 million years ago, in a period known as the Permian-Triassic boundary, was the largest of all. About 90 percent of species disappeared."
Pre-emptive correction (Score:3, Informative)
Re:Pre-emptive correction (Score:2)
Re:Pre-emptive correction (Score:1)
From the lecture: "By Late Triassic (and maybe during the Middle Triassic), true dinosaurs finally appear"
Re:Pre-emptive correction (Score:2)
Re:Pre-emptive correction (Score:3, Informative)
Time scale works like this (from larger to smaller): Eon -> Era -> Period -> Epoch -> Age
The Permian was the last period of the Paleozoic Era(which ending with the mass extinction). This was followed by the Mesozoic Era (whose first period was the Triassic). While Dinosaurs first appeared in the Triassic they become dominant during the Jurassic. Dinosaurs first appeared in the Carnian age (227 to 221 million years ago, dur
Re:Pre-emptive correction (Score:2)
I wonder what will take the dominant role after we humans are finished with Earth (we're in a perioid of very rapid extinction of species, thanks to human activity, and I don't really see the direction changing any time soon...)
Re:Pre-emptive correction (Score:4, Informative)
The dino extinction is called the K-T extinction, for Cretaceous/Tertiary (it makes sense in German, I imagine), and the one in question would be the P-T extinction, for Permian/Triassic. So this is the previous huge mass extinction event to the K-T extinction. The Dinosauria branch off from the Reptilia in early Triassic, and all Dinosauria except the Aves die off at the K-T event.
The P-T was bigger than the K-T.
Naturally-occurring Buckyballs? (Score:3, Interesting)
I thought it took precise conditions to get them to form. And for these to have captured gases inside...
Weird...
GTRacer
- Go-o-o-o-al!
Re:Naturally-occurring Buckyballs? (Score:4, Informative)
Re:Naturally-occurring Buckyballs? (Score:2)
Another article (Score:3, Informative)
Impact-caused volcanic activity (Score:3, Interesting)
Something to note is that both cases here involves a meteor impact on the opposite side of the earth from the eruptions. Coincidence?
Re:Impact-caused volcanic activity (Score:1)
If there's an impact on one side of a sphere (or oblate spheroid, the Earth) shockwaves are going to travel along the surface boundary. As the waves radiate away from the impact site, they end up converging on the opposite side of the sphere (the antipode).
If the eruptions are directly linked to the impact and the tectonic stresses from it, the stress is greatest at the impact site and second greatest at the antipode of the impact site.
The new Scientific American has a great artic
Re:Impact-caused volcanic activity (Score:3, Informative)
Coincidence? Nope. When a spherical body like the earth or any other of the terrestrial planets is hit by a suficiently large meteor the shockwave is focused by the spherical shape and arrive at the exact opposite side of the planet resulting in a massive earthquake (actually 3, one from each of the three types of vibrations (sound) that travel through the earth with differ
Re:Impact-caused volcanic activity (Score:2, Informative)
Your hypothesis has a few problems..
a) The Earth is not perfectly spherical, and it is distinctly non-Isotropic.
b) You need to include some calculations on how much energy would actually be available from the known crater. Even under generous assumptions, we are looking at a magnitude 10.5 earthquake at best.
c) Surface waves are strongly attenuated in the crust, which is strongly anisotropic. The energy arriving at the other side of the planet would be negligable. P and S waves would not be focusse
Re:Impact-caused volcanic activity (Score:2)
I agree that
I once had a theory.... (Score:1)
Technically I see no reason why this can't be true, since the time span is so long between mass extinctions (not like the dinosaurs one but more like the one described in this article where almost all life is destroyed),
Re:I once had a theory.... (Score:1)
I know slashdot is slow on news but.... (Score:2, Funny)
I know slashdot is slow on getting news but...
250 million years?
Re:I know slashdot is slow on news but.... (Score:1)
Too busy at Free6 [free6.com] to post, I'm sure. :)
It's amazing... (Score:1)
Re:Tragedy of this all (Score:1)
The article itself emphasizes the speculative nature of the conclusion by rating the probability of the P-T extinction/asteroid link as a 3 or 4 on a scale of 10, as opposed to a solid 10 for the dinosaur-killing K-T extinction 65 million years ago.
And bringing evolution into the discussion qualifies your post as a bon
Re:Tragedy of this all - What tragedy? (Score:1)
To believe in a technique whose calibration results are incorrect by six or more orders of magnitude is so absurd that it defies comprehension.
The number of years in orders of magnitude really doesn't matter if the total years is similarly scaled.
If you are suggesting the entire technique gives results that have errors that are off by that order of magnitude for all r
Re:Tragedy of this all - What tragedy? (Score:1)
Re:Tragedy of this all - What tragedy? (Score:1)
How ah -
("comforting, you were thinking?")
- but then again -
I was hoping for something to turn my head around.
As a person with a sense of adventure, I am always hoping for results that don't 'fit' - I think you'll find most scientists think that way - Quite the opposite of having a - what is it a faith at the center of their belief system (quite the oxymoron there - eh?)
You can start here [onafarawayday.com]. (Follows pre-Enlightment model by
Re:Tragedy of this all - What tragedy? (Score:1)
and
Another claim:
Maybe you found a different link?
Discussion obviously ended - Perhaps you're writing to/for someone else?
Re:Tragedy of this all - What tragedy? (Score:1)
I suspect that what you are alluding to is the K-Ar dating of Hawiian and St Helens Basalts/Andesites.
There are two explanations you haven't mentioned. One is that we are measuring the ages of crystallisition of xenocrysts (crystals incorporated from the country rock) or xenoliths (rock fragments from the country rock). Without references and thin sections, we can't know this.
The other is that we are measuring the amount of Ar incorporated at formation, giving a falsely old age. If this is the case,
Re:Tragedy of this all - What tragedy? (Score:1)
Re:Tragedy of this all - What tragedy? (Score:1)
Re:Tragedy of this all - What tragedy? (Score:1)
When a *strange* result comes back - it's looked at. Not simply chucked for a dogma - in fact - finding a flaw in an established procedure would be the biggest break a 'tenure-minded, publish or perish' researcher could hope for. A break to a new methodology - early in their career - sounds good to me.
Choosing a *flawless* (in your context) method instead of choosing something the data can back up is a sure way to *perish* in the resea
Re:Tragedy of this all - What tragedy? (Score:1)
Take known age rock. Test it radiometrically. Answer is absurd.
Fair enough - since the answer is not absurd, there is no problem.
Try this:
Take a 1 meter rule.
Use it to measure the width of a hair, previously measured with a microscope micrometer, using your eye and rounding to the nearest mark. (say, 1cm or 0cm)
Answer is 'absurd', or inaccurate.
Therefore this concept of 'Meters' is useless!
Re:Tragedy of this all - What tragedy? (Score:1)
Potassium-argon dating is accurate from 4.3 billion years (the age of the Earth) to about 100,000 years before the present.
So using it on 10 year old rocks would be absurd, then.
By the way, radiometric dating (and 'old earth geology', as you would put it) is used commercially by the oil industry. Do you think that they would be willing to waste 10s of millions of dollars drilling dry wells just to prop up some conspiricy?
Re:Tragedy of this all - What tragedy? (Score:1)
How can you miss a point that is so simple?
How can you continue to ignore the explanations? A more complete reference if here. [talkorigins.org]
Re:Tragedy of this all - What tragedy? (Score:1)
They miss the point because their religion (humanism) and its core value (evolution) demand it of them.
This is called 'projection'. And by the way; humanism is a set of values, not a religion, and evolution is a scientific theory, not a value.
she needs prayers, lots. Won't go into why.
Oh. Please do.
Re:Tragedy of this all - What tragedy? (Score:1)
I answered that, explaining why it was precisely the method we must use to falsify K/Ar dating.
No; using a technique inappropriately does not falsify it. You could falsify it by finding a place where the relative ages of rocks as determined by structural geology failed to match K-Ar ages on those rocks.
Regarding the more recent one.. you really should read the papers you cite. ALL it is saying is that phenocrysts (Which are slowly grown crystals in the magma chamber) will date older than the groundm
Re:Tragedy of this all - What tragedy? (Score:1)
But Humanism is a religion by its own descriptions. From here:
Ther're talking rubbish, or just trying to make it palatable to a US audience.
Re:Tragedy of this all - What tragedy? (Score:1)
You may not like the fact that humanists call humanism a religion, but they do.
No, some American humanists want to call it a reliegon. Certainly I wouldn't, and many people who describe themselves as humanist wouldn't.
I take it that you've abandoned your uninformed attack on radiometric dating, since you've started witnessing. Out of interest, if you are so protected and stuff, why do you have to post anomously? To me that reeks of cowardice and insecurity.
Re:Tragedy of this all - What tragedy? (Score:1)
First, your analogy is wrong; it's more a case of the speedomoter saying 10 when you're doing less than 10.
Second, you haven't demonstrated radiometric dating doing what you claim; as I have repeatedly pointed out, IF you want to date something, you have to know exactly what it is you are dating. If you date a crystal in a volcanic rock, you are dating the time of crystalisation, NOT the time of eruption. Do you understand this? Do you realise that in a course on radiometric dating, the majority of the
Minor Planets Currently Known (Score:2, Informative)
This page [nasa.gov] updates regularly on newly discovered objects.
There are many more to be found. Though the risk of an impact like the one believed to have been involved is very slight.