Ribose, a sugar needed for life, has been detected in meteorites

Prawnapple

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Space rocks that fell to Earth contain ribose, an essential molecule for life’s genetic machinery, and other related sugars. The finding, reported online November 18 in Proceedings of the National Academy of Sciences, lends support to the idea that many of life’s ingredients were delivered to Earth by interplanetary debris.

Many organic molecules have been found in space. Comet Lovejoy, for example, carts around sugar and alcohol, the base ingredients for a decent interplanetary cocktail (SN: 10/23/15). But until now, no one had confirmed an extraterrestrial source for ribose. This molecule forms part of the sugar-phosphate backbone of RNA, molecular workhorses within cells responsible for reading and carrying out instructions encoded in DNA.
Further reading:
 

Ponderer

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Did the meteorites have/contain traces of Ribose before they entered the atmosphere?
Is it possible that they were "contaminated" with Ribose after they entered the atmosphere?
 

Asgard85

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Did the meteorites have/contain traces of Ribose before they entered the atmosphere?
Is it possible that they were "contaminated" with Ribose after they entered the atmosphere?
From the NASA article:

Since Earth is awash with life, the team had to consider the possibility that the sugars in the meteorites simply came from contamination by terrestrial life. Multiple lines of evidence indicate contamination is unlikely, including isotope analysis. Isotopes are versions of an element with different mass due to the number of neutrons in the atomic nucleus. For example, life on Earth prefers to use the lighter variety of carbon (12C) over the heavier version (13C). However, the carbon in the meteorite sugars was significantly enriched in the heavy 13C, beyond the amount seen in terrestrial biology, supporting the conclusion that it came from space.
 
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Ponderer

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From the NASA article:

Since Earth is awash with life, the team had to consider the possibility that the sugars in the meteorites simply came from contamination by terrestrial life. Multiple lines of evidence indicate contamination is unlikely, including isotope analysis. Isotopes are versions of an element with different mass due to the number of neutrons in the atomic nucleus. For example, life on Earth prefers to use the lighter variety of carbon (12C) over the heavier version (13C). However, the carbon in the meteorite sugars was significantly enriched in the heavy 13C, beyond the amount seen in terrestrial biology, supporting the conclusion that it came from space.
The "Ribose from space" survived the incinerating heat generated by the carrier meteorite burning through the atmosphere?
This article is not the first (nor will it be the last) that be a load of hogwash.
 
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Prawnapple

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Did the meteorites have/contain traces of Ribose before they entered the atmosphere?
Is it possible that they were "contaminated" with Ribose after they entered the atmosphere?
Did the meteorites have/contain traces of Ribose before they entered the atmosphere?
Yes, that's what it's all about. Panspermia

Is it possible that they were "contaminated" with Ribose after they entered the atmosphere?
Not sure, I'd wager unlikely as it's found inside the core of the meteorite as well.

The "Ribose from space" survived the incinerating heat generated by the carrier meteorite burning through the atmosphere?
This article is not the first (nor will it be the last) that be a load of hogwash.
The "Ribose from space" survived the incinerating heat generated by the carrier meteorite burning through the atmosphere?
Yes it did, here's the explanation:
Most iron-nickel meteorite chunks found swiftly after landing are covered in frost. The atmospheric heating melts and ablates the outer layer such that the inner portion does not heat. The extreme cold of the inside means that once it lands, the heat on the remaining outside is quickly equalized and the surface is nearly as cold as it was in space. It begins warming overall as it sits in a warm atmosphere and on warm ground.
 

Ponderer

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It is highly probable (almost certain) that the meteorite was simply "contaminated with Ribose" at some or other stage after it entered the atmosphere.
 

3WA

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It is highly probable (almost certain) that the meteorite was simply "contaminated with Ribose" at some or other stage after it entered the atmosphere.
It's a real pity PNAS didn't call on your expertise to review the article. Real missed opportunity and now the scientific literature, like the meteorite in question, is needlessly contaminated.

On a serious note, if the ribose is from earth, how do you explain the carbon isotope signature? Why doesn't it have light carbon enrichment?
 

Ponderer

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It's a real pity PNAS didn't call on your expertise to review the article. Real missed opportunity and now the scientific literature, like the meteorite in question, is needlessly contaminated.

On a serious note, if the ribose is from earth, how do you explain the carbon isotope signature? Why doesn't it have light carbon enrichment?
Firstly.
How long after entry was the test performed.
What be the length of time that the meteorite laid on the ground.

Secondly.
How porous is the meteorite.
Mosses for example readily penetrate porous rock.

Thirdly.
Has it been confirmed that the core of the meteorite was indeed shielded from the incendiary heat the meteorite was subjected to when it entered the atmosphere.

Fourthly.
What is the average % of C13 measured in meteorites.
When a meteorite passes through the atmosphere, it is obviously exposed to the gasses of/in the atmosphere.
As C13 is formed in the upper atmosphere, the upper atmosphere would naturally have higher levels of C13.
One would therefore expect meteorites that passed through the upper atmosphere to contain higher levels of C13.
 

3WA

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Firstly.
How long after entry was the test performed.
What be the length of time that the meteorite laid on the ground.

Secondly.
How porous is the meteorite.
Mosses for example readily penetrate porous rock.

Thirdly.
Has it been confirmed that the core of the meteorite was indeed shielded from the incendiary heat the meteorite was subjected to when it entered the atmosphere.

Fourthly.
What is the average % of C13 measured in meteorites.
When a meteorite passes through the atmosphere, it is obviously exposed to the gasses of/in the atmosphere.
As C13 is formed in the upper atmosphere, the upper atmosphere would naturally have higher levels of C13.
One would therefore expect meteorites that passed through the upper atmosphere to contain higher levels of C13.
All your questions are asking me to report numbers that are widely available in the public domain. Can I suggest you read the resources below, which will answer all your questions (I won't trouble myself with reposting the numbers here) and allow us to move beyond basic questions to more advanced points of discussion (for example, instead of simply asking me to report the number, we could discuss whether the way in which the number was determined is accurate).

Furthermore, doing the pre-reading will help you realise that people have been thinking about the contamination problem since the 60s and have fairly sophisticated ways of addressing it.

1.) The peer-reviewed paper:


2.) The supplementary information attached to the paper:


3.) J. M. Hayes, Organic constituents of meteorites—A review. Geochim. Cosmochim. Acta 31, 1395–1440 (1967)

4.) J. R. Cronin, C. B. Moore, Amino acid analyses of the Murchison, Murray, and Allende carbonaceous chondrites. Science 172, 1327–1329 (1971)

5.) C. M. O. Alexander, M. Fogel, H. Yabuta, G. D. Cody, The origin and evolution of chondrites recorded in the elemental and isotopic compositions of their macromolecular organic matter. Geochim. Cosmochim. Acta 71, 4380–4403 (2007)

6.) M. A. Teece, M. L. Fogel, Stable carbon isotope biogeochemistry of monosaccharides in aquatic organisms and terrestrial plants. Org. Geochem. 38, 458–473 (2007)

If you have trouble getting any of the papers above, try Sci-Hub. I know it's a lot of reading, but unfortunately, this is simply the entry price to intelligibly discuss modern science.


To get to the crux of your contamination argument, if the meteorite is contaminated by terrestrial matter, why are the contaminants dissimilar to organic matter? If you find dog sh*t in your yard, you don't assume the contamination came from a cat.
 

Ponderer

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All your questions are asking me to report numbers that are widely available in the public domain. Can I suggest you read the resources below, which will answer all your questions (I won't trouble myself with reposting the numbers here) and allow us to move beyond basic questions to more advanced points of discussion (for example, instead of simply asking me to report the number, we could discuss whether the way in which the number was determined is accurate).

Furthermore, doing the pre-reading will help you realise that people have been thinking about the contamination problem since the 60s and have fairly sophisticated ways of addressing it.

1.) The peer-reviewed paper:


2.) The supplementary information attached to the paper:


3.) J. M. Hayes, Organic constituents of meteorites—A review. Geochim. Cosmochim. Acta 31, 1395–1440 (1967)

4.) J. R. Cronin, C. B. Moore, Amino acid analyses of the Murchison, Murray, and Allende carbonaceous chondrites. Science 172, 1327–1329 (1971)

5.) C. M. O. Alexander, M. Fogel, H. Yabuta, G. D. Cody, The origin and evolution of chondrites recorded in the elemental and isotopic compositions of their macromolecular organic matter. Geochim. Cosmochim. Acta 71, 4380–4403 (2007)

6.) M. A. Teece, M. L. Fogel, Stable carbon isotope biogeochemistry of monosaccharides in aquatic organisms and terrestrial plants. Org. Geochem. 38, 458–473 (2007)

If you have trouble getting any of the papers above, try Sci-Hub. I know it's a lot of reading, but unfortunately, this is simply the entry price to intelligibly discuss modern science.


To get to the crux of your contamination argument, if the meteorite is contaminated by terrestrial matter, why are the contaminants dissimilar to organic matter? If you find dog sh*t in your yard, you don't assume the contamination came from a cat.
Did you note the technique that was used to extract the sample from the meteorite?
 

Splinter

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I already know the answer to that.
Yep. Also, he woouldn't answer. Like when I asked him half a dozen times or more if he had ever fully read a book from Dawkins (yes, again he was dismissing something out of hand).
 
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