Real Science Friday: Comets

[fool]

Um...Bob puts a link to his errata page right on the front page of his website. Try again Grainite.

I didn't see this one on there;
http://www.theologyonline.com/forums/showthread.php?t=20499&highlight=neanderthal+flute

 

[Jefferson]

Still waiting for a response to post #38.

Any takers?

 

[Tyrathca]

Still waiting for a response to post #38.

Any takers?

You didn't post anything to respond to. There is a link to a book that I have to buy, not a link to any predictions on comet composition. Note I said PREDICTIONS, the show you also linked states that it was made after NASAs data. By the way is your entire argument based on the JUST the presence of olivine or is it that the comets entire composition is earth-like?

 

[gsweet]

Still waiting for a response to post #38.

Any takers?

I still fail to see how you've made a point. Are you focusing on just the surprise of the scientists involved in the Stardust program, or the actual data? If the data is indicative of something, then what and why?

Just to get things rolling:
The identification of crystalline olivine is not really far fetched at all; neither is that of sulfides and other silicates. Remember that these minerals are common throughout the solar system and many constitute the makeup of other planets. Case in point, the moon: anorthosite (a major component of lunar highlands) is dominantly anorthitic plagioclase feldspar (high Ca end member). We also find anorthisite on earth (e.g., the Duluth Complex, Minnesota). Another example: I am currently holding a slice of a pallasite meteorite composed entirely of olivine phenocrysts in a nickle-iron matrix. Isotopic character of pallasites is quite different from anything we see here on earth, suggesting that I may be holding a fragment of an extra-terrestrial planet's core or lower mantle. Basically, the identification of the variety of silicates and sulfides in the Stardust samples suggests a host of new ideas about comet formation, composition and whatnot. I don't see how this implies Walt Brown's hypothesis.

 

[Jefferson]

Note I said PREDICTIONS, the show you also linked states that it was made after NASAs data.

Here's a quote from the show...

Walt Brown: Olivine is one of the most common minerals [found in the crust of the earth].

Bob Enyart: And do they find olivine in comets?

Walt Brown: Aboslutely. And I predicted it beforehand. I put it in writing beforehand. You've seen it in the book that was published years before.

Bob Enyart: I sure have and I've made that argument. In fact, when NASA was getting ready to slam into this comet, I called some scientist friends and told them what they would find and thanks to you Walt Brown, my prediction to them was true. It was really your prediction.

Walt Brown: And the chief scientist of one of those space programs got ahold of the chapter before it was published in 2001. He saw the prediction. And he was making just the opposite prediction. His name is Don Brownlee.

 

[gsweet]

Here's a quote from the show...

Walt Brown: Olivine is one of the most common minerals [found in the crust of the earth].

Bob Enyart: And do they find olivine in comets?

Walt Brown: Aboslutely. And I predicted it beforehand. I put it in writing beforehand. You've seen it in the book that was published years before.

Bob Enyart: I sure have and I've made that argument. In fact, when NASA was getting ready to slam into this comet, I called some scientist friends and told them what they would find and thanks to you Walt Brown, my prediction to them was true. It was really your prediction.

Walt Brown: And the chief scientist of one of those space programs got ahold of the chapter before it was published in 2001. He saw the prediction. And he was making just the opposite prediction. His name is Don Brownlee.

Olivine is not one of the most abundant crustal minerals. It is an (igneous) ultramafic mineral, and is not associated with the predominantly granitic (felsic) components of the earth's crust. It is more readily associated (volumetrically) with deeper asthenospheric melts, and crystallizes as a cumulate phenocryst only at depth under high heat and pressures (regardless of Mg and Fe ratios). In fact, olivine is extremely unstable at the earth's surface (low pressure and temperature) and the few examples we find are either very altered or very young.

 

[Flipper]

If you read the wiki entry on Olivine, you learn the following:

Mg-rich olivine has also been discovered in meteorites, on Mars, and on Earth's moon. Such meteorites include chondrites, collections of debris from the early solar system, and pallasites, mixes of iron-nickel and olivine. The spectral signature of olivine has been seen in the dust disks around young stars. The tails of comets (which formed from the dust disk around the young Sun) often have the spectral signature of olivine, and the presence of olivine has recently been verified in samples of a comet from the Stardust spacecraft.

So it doesn't sound like Olivine is unusual in the solar system or in the universe at large.

Also, the presence of Olivine in cometary composition can't have been that shocking to the Wild II scientists, because I found a paper on it from 2005.

Supernova Olivine from Cometary Dust
Scott Messenger,1* Lindsay P. Keller,1 Dante S. Lauretta2
An interplanetary dust particle contains a submicrometer crystalline silicate aggregate of probable supernova origin. The grain has a pronounced enrichment in 18O/16O (13 times the solar value) and depletions in 17O/16O (one-third solar) and 29Si/28Si (<0.8 times solar), indicative of formation from a type II supernova. The aggregate contains olivine (forsterite 83) grains <100 nanometers in size, with microstructures that are consistent with minimal thermal alteration. This unusually iron-rich olivine grain could have formed by equilibrium condensation from cooling supernova ejecta if several different nucleosynthetic zones mixed in the proper proportions. The supernova grain is also partially encased in nitrogen-15-rich organic matter that likely formed in a presolar cold molecular cloud.

Note that this Olivine is significantly different in its composition to that expected from solar system formation, but in keeping with the predicted composition of ejecta from Type II supernovas.

There's even evidence of extrasolar olivine, dating back to at least 1998:

Astronomers at the universities of Amsterdam, Louvain, Groningen and Utrecht have found proof that planets can form around old, dying stars. In the vicinity of the Red Rectangle, an old binary star in the Monoceros constellation, they have detected a ring of matter constituting the first stage of planet formation. Their results will be published in Nature on 26 February. It had previously been assumed that planets can form only round new-born stars.

Young stars are frequently surrounded by a flattened ring of gas and particles left over from the star formation process. The particles can join together to form larger and larger pieces that eventually grow to the size of planets.
Observations made using the Dutch-German short wavelength spectrometer (SWS) on board the Infrared Space Observatory (ISO), a mission of the European Space Agency (ESA), have shown that such rings are rich in silicates. The particular form and composition of the silicate, crystalline olivine, occurs on the Earth and in comets, which are the remnants of abortive planet formation. It thus appears to be an important constituent in the formation of planets.

From SWS observations it now appears that the ring of matter around the Red Rectangle binary contains large particles with a great deal of crystalline olivine. The Red Rectangle consists of two old neighbouring stars, one of which was a red giant and is now in the process of becoming a white dwarf. This star is thus very old. The olivine is of the same type as that found in the rings round young new-born stars, on the Earth and in comets. It is the first time that this formative constituent of planets has been found in the ring round an old, dying star.

As far as the other ingredients of your comet go, I note that all of them (and maybe Olivine too, as it's a silicate) are believed to be found on Titan, a planet with much lower gravity than earth. Why assume that earth, with its high escape velocity, is the source of cometary material?

Why assume that hydroplate theory is the better explanation? Hydroplate theory has already been shown to be totally deficient, what with its impossible aerobraking physics and the vast amounts of energy released that would inevitably make life on earth completely unsustainable.

It's an attempt to make sense of an already incoherent young earth model, with all its many other apparently unsurmountable problems (such as its failure to make any sense of the fossil or geological record record, its incoherence in explaining the distribution and diversity of life, its inability to be reconciled with any known dating method, etc). Using Hydroplate theory to help out YEC is like giving a broken crutch to a double-amputee.

Comets should be low on the list of Walt Brown's priorities when it comes to making the case for YEC.

 

[Tyrathca]

Here's a quote from the show...

And the show was after the data came out, where is a source for him saying this BEFORE the data came out. What part of "prediction" don't you understand?

 

[Stripe]

I still fail to see how you've made a point. Are you focusing on just the surprise of the scientists involved in the Stardust program, or the actual data? If the data is indicative of something, then what and why?

I think the point is that comets started life on earth. And the evidence supports that assumption.

Just to get things rolling:
The identification of crystalline olivine is not really far fetched at all; neither is that of sulfides and other silicates. Remember that these minerals are common throughout the solar system and many constitute the makeup of other planets. Case in point, the moon: anorthosite (a major component of lunar highlands) is dominantly anorthitic plagioclase feldspar (high Ca end member). We also find anorthisite on earth (e.g., the Duluth Complex, Minnesota). Another example: I am currently holding a slice of a pallasite meteorite composed entirely of olivine phenocrysts in a nickle-iron matrix. Isotopic character of pallasites is quite different from anything we see here on earth, suggesting that I may be holding a fragment of an extra-terrestrial planet's core or lower mantle. Basically, the identification of the variety of silicates and sulfides in the Stardust samples suggests a host of new ideas about comet formation, composition and whatnot. I don't see how this implies Walt Brown's hypothesis.

That's a lot of conjecture that counters nothing. Olivine forms commonly on earth. To find it in space is evidence material could have been launched from earth.

Olivine is not one of the most abundant crustal minerals. It is an (igneous) ultramafic mineral, and is not associated with the predominantly granitic (felsic) components of the earth's crust. It is more readily associated (volumetrically) with deeper asthenospheric melts, and crystallizes as a cumulate phenocryst only at depth under high heat and pressures (regardless of Mg and Fe ratios). In fact, olivine is extremely unstable at the earth's surface (low pressure and temperature) and the few examples we find are either very altered or very young.

Nobody specified the location. It's either common on earth or it's not. Which is it?

 

[Stripe]

And the show was after the data came out, where is a source for him saying this BEFORE the data came out. What part of "prediction" don't you understand?

Not to get into a debate over who said what when, but the usefulness of a prediction doesn't fail after it is shown correct.

 

[Tyrathca]

Not to get into a debate over who said what when, but the usefulness of a prediction doesn't fail after it is shown correct.

But its not really a prediction when you already know the answer is it? The guy could very easily have just said comets are likely to be earth-like in composition and nothing more, then when olivine is found claim he predicted it (by saying olivine is common to earth). That would be disingenuous and thus I need a source from before to know he actually predicted it not retrospectively adapted his claims to fit the data. This isn't an unusual request for science so I fail to see what the problem is.

 

[gsweet]

I think the point is that comets started life on earth. And the evidence supports that assumption.

Right. I understand the point that was being made, but the data doesn't support it.

That's a lot of conjecture that counters nothing. Olivine forms commonly on earth. To find it in space is evidence material could have been launched from earth.

That is not conjecture, Stripe, it's multiple examples of why olivine found in space does not have to come from this planet. Furthermore, the isotopic character of olivine in meteorites is distinct from that which we find on earth, demonstrating that extraterrestrial olivine does exist (backed by Flipper's research).

Nobody specified the location. It's either common on earth or it's not. Which is it?

No, that's fairly well understood mineral physics; olivine does not form commonly on earth, but rather in earth. I'll quote Mr. Brown again:

Walt Brown: Olivine is one of the most common minerals [found in the crust of the earth].

Phenocrystic olivine is not that common in crustal rocks; it is more prominent in shallow asthenospheric rocks, where the TPX (temp, pressure, composition) environment for olivine crystallization is more sustainable. But whatever, that's just me nitpicking.

Without the isotopic data, the fact that phenocrystic olivine is found in asteroids in no way demands an origin from this planet. In fact, as olivine (and other silicates) are found on other stable bodies throughout the solar system, one might assume that the cumulative volume of a mineral such as olivine within our planet is vastly trumped by that of the remaining solar system. Add in the distinct discrepancies between isotopic data sets (again, Flipper's find) of terrestrial and extra-terrestrial samples, and that's pretty definitive evidence that the chondrite/pallasite/asteroid olivine is not of this planet.

 

[Flipper]

That's a lot of conjecture that counters nothing. Olivine forms commonly on earth. To find it in space is evidence material could have been launched from earth.

It doesn't explain how Olivine comes to be found in accretion disks around other stars. Just how big do you think the earth was in pre-flood days?

 

[Jefferson]

And the show was after the data came out, where is a source for him saying this BEFORE the data came out. What part of "prediction" don't you understand?

NASA's probe passed by the Wild 2 comet in 2004. Walt Brown's prediction came 3 years BEFORE that when his book was published in 2001. What part of "BEFORE" don't you understand?

You actually think the prediction is nullified just because we air a show discussing his (then 6 year old) prediction 3 years AFTER NASA's evidence came in? You're kidding, right? That would be like me saying, if you predicted 6 months ago that the Saints would win the Super Bowl, your prediction would be nullified if you ever talk about your prediction anytime AFTER the Super Bowl is over.

 

[Tyrathca]

NASA's probe passed by the Wild 2 comet in 2004. Walt Brown's prediction came 3 years BEFORE that when his book was published in 2001. What part of "BEFORE" don't you understand?

*sigh* The part where you provide a source that itself explicitly said was after the probe. You can say he said it before all you want but I require a source. What you have provided is the equivalent of a show in 2002 with a guest who said he predicted 9/11 in 1999, what I need is the 1999 prediction not the 2002 claim of prediction you keep supplying.

Not that it really matters now since as other posters have shown the presence of olivine is not necessarily (or even likely) of earth origin despite this being part of the claim.

You actually think the prediction is nullified just because we air a show discussing his (then 6 year old) prediction 3 years AFTER NASA's evidence came in? You're kidding, right?

No genius, I'm saying a show 3 years after the data is not evidence of making a prediction before the data. :duh

That would be like me saying, if you predicted 6 months ago that the Saints would win the Super Bowl, your prediction would be nullified if you ever talk about your prediction anytime AFTER the Super Bowl is over.

No. But if you can't provide a source of you talking about it before the super bowl then people are bound to be skeptical until you do, all I want (so far) is evidence he made his prediction before the data rather than him just saying he did afterwards.

 

[The Barbarian]

farenheight

Forget peer review; get a spell checker.

 

[Stripe]

But its not really a prediction when you already know the answer is it?

Actually, yeah, it is in a scientific context.

The guy could very easily have just said comets are likely to be earth-like in composition and nothing more, then when olivine is found claim he predicted it (by saying olivine is common to earth). That would be disingenuous and thus I need a source from before to know he actually predicted it not retrospectively adapted his claims to fit the data. This isn't an unusual request for science so I fail to see what the problem is.

The problem is you're all too eager to discuss matters pertaining to a guy's reputation rather than pertaining to actual facts.

Right. I understand the point that was being made, but the data doesn't support it.

I'm not sure that you do. You still don't seem to be responding in kind.

That is not conjecture, Stripe, it's multiple examples of why olivine found in space does not have to come from this planet.

Olivine in space doesn't have to come from this planet. It is merely assumed that the olivine in comets did. As far as I can tell you've nothing in the way of data that denies that possibility.

Furthermore, the isotopic character of olivine in meteorites is distinct from that which we find on earth, demonstrating that extraterrestrial olivine does exist (backed by Flipper's research).

I would not doubt that olivine in comets is different from olivine on earth. In fact it's not all that surprising. Are you claiming that the olivine found could by no means have formed on earth? I find that very unlikely.

No, that's fairly well understood mineral physics; olivine does not form commonly on earth, but rather in earth. I'll quote Mr. Brown again:

Oh dear. If your argument is based on a single preposition from a quote sourced from a radio show by a third party I'm afraid you're going to just get ignored by me.

Please tell me you're not making this argument.

Phenocrystic olivine is not that common in crustal rocks; it is more prominent in shallow asthenospheric rocks, where the TPX (temp, pressure, composition) environment for olivine crystallization is more sustainable. But whatever, that's just me nitpicking.

I'm sure a man who has written and studied extensively on the matter understands all this pretty well. With a quick search of his readily available material I found a quote you could use that you might not have such a problem with. Please, if you're interested in the idea, do some reading on it before nit picking on prepositional usage. :up:

Without the isotopic data, the fact that phenocrystic olivine is found in asteroids in no way demands an origin from this planet.

Sure. It could have come from another planet. You have any suggestions?

It doesn't explain how Olivine comes to be found in accretion disks around other stars. Just how big do you think the earth was in pre-flood days?

:doh:

Forget peer review; get a spell checker.

:yawn:

 

[gsweet]

I'm not sure that you do. You still don't seem to be responding in kind.

Olivine in space doesn't have to come from this planet. It is merely assumed that the olivine in comets did. As far as I can tell you've nothing in the way of data that denies that possibility.

See the stable and radiogenic isotope data...

I would not doubt that olivine in comets is different from olivine on earth. In fact it's not all that surprising. Are you claiming that the olivine found could by no means have formed on earth? I find that very unlikely.

I am in fact stating this; the bulk isotopic signature of earth's olivine is relatively unique, and the order of magnitude difference between it and extra-terrestrial olivine is pretty definitive. What we find in asteroids and meteorites could not have come from this planet...

Oh dear. If your argument is based on a single preposition from a quote sourced from a radio show by a third party I'm afraid you're going to just get ignored by me.

Please tell me you're not making this argument.

Well, given the layout of Mr. Brown's hydroplate theory, I consider this pretty important. Let me ask a few questions first, though:
-How far below the surface of the earth was the inferred "water layer"?
-What mechanism was proposed for the "eruption" of the water to the surface?

I'm sure a man who has written and studied extensively on the matter understands all this pretty well. With a quick search of his readily available material I found a quote you could use that you might not have such a problem with. Please, if you're interested in the idea, do some reading on it before nit picking on prepositional usage. :up:

I shall.

Sure. It could have come from another planet. You have any suggestions?

Sure: any other of the billions or trillions of planets in our galaxy. Or more specifically, fragments of them. The fact that asteroids seem to be composed of a variety of exotic minerals suggests that they have scavenged debris that is already floating around in space, composed of ice particles, dust, and fragments of various rocks and/or minerals from planets that are no longer present. I'll give you an example though; were pallasite slice I own to have come from this planet, it would have originated in the deep asthenosphere along the mantle-core boundary. The high Mg olivine and nickle-iron matrix implies element differentiation having taken place, and the heavier elements preferentially concentrating deeper in the planet (hence why we refer to a nickle-iron core for this planet).

So tell me then, what about the minerals found on the asteroid tell you that they originated on earth? Disregarding the isotope data even, why couldn't they have originated from pretty much anywhere else besides earth?

 

[Stripe]

I am in fact stating this; the bulk isotopic signature of earth's olivine is relatively unique, and the order of magnitude difference between it and extra-terrestrial olivine is pretty definitive. What we find in asteroids and meteorites could not have come from this planet...

What conditions would have to have been different for the earth to have produced the comets we see?

Well, given the layout of Mr. Brown's hydroplate theory, I consider this pretty important. Let me ask a few questions first, though:
-How far below the surface of the earth was the inferred "water layer"?
-What mechanism was proposed for the "eruption" of the water to the surface?

That's going to be a fairly in depth discussion. Have you the time for it?

I shall.

Sure: any other of the billions or trillions of planets in our galaxy. Or more specifically, fragments of them. The fact that asteroids seem to be composed of a variety of exotic minerals suggests that they have scavenged debris that is already floating around in space, composed of ice particles, dust, and fragments of various rocks and/or minerals from planets that are no longer present. I'll give you an example though; were pallasite slice I own to have come from this planet, it would have originated in the deep asthenosphere along the mantle-core boundary. The high Mg olivine and nickle-iron matrix implies element differentiation having taken place, and the heavier elements preferentially concentrating deeper in the planet (hence why we refer to a nickle-iron core for this planet).

The orbits of comets and meteorites preclude them from being extra-solar objects. I believe we are yet to detect an incoming object of a meteoric or comitic chuckle nature.

So tell me then, what about the minerals found on the asteroid tell you that they originated on earth? Disregarding the isotope data even, why couldn't they have originated from pretty much anywhere else besides earth?

I'm not the right man to be explaining mineralogy. Especially not to you.

I can explain some physical processes, so if you think mineralogy trumps the physics then I'd be eager to know why and how that might require an adjustment to my ideas.

 

[gsweet]

I'm going to preempt this with the comment that I'm not entirely sober (it's been a rough day with the new data sets and scotch was a necessity).

What conditions would have to have been different for the earth to have produced the comets we see?

Differentiation of isotopes within the earth is determined by quite a few chemical and physical parameters (many levels of partial melting and fractional crystallization). In this case we're looking at stable isotope geochemistry, so in order for the values we're seeing in "astro olivine" to be generated by the earth's mantle, we'd have to see significantly less elemental fractionation and differentiation. Basically, everything we see when it comes to earth's compositional variation suggests otherwise.

That's going to be a fairly in depth discussion. Have you the time for it?

Probably not We'll have to get back to it at some point...

The orbits of comets and meteorites preclude them from being extra-solar objects. I believe we are yet to detect an incoming object of a meteoric or comitic chuckle nature.

Say what now? This I have not heard...you'll have to provide some sources for this.

I'm not the right man to be explaining mineralogy. Especially not to you.

I can explain some physical processes, so if you think mineralogy trumps the physics then I'd be eager to know why and how that might require an adjustment to my ideas.

Mineralogy will never trump the physics; in fact, mineralogy and physics agree quite well...