Slashdot is powered by your submissions, so send in your scoop

 



Forgot your password?
typodupeerror
Earth Space NASA News Science

Asymmetric Molecule, Key To Life, Detected In Space For First Time (yahoo.com) 56

schwit1 quotes a report from Yahoo News: Scientists for the first time have found a complex organic molecule in space that bears the same asymmetric structure as molecules that are key to life on Earth. The researchers said on Tuesday they detected the complex organic molecule called propylene oxide in a giant cloud of gas and dust near the center of the Milky Way galaxy. Akin to a pair of human hands, certain organic molecules including propylene oxide possess mirror-like versions of themselves, a chemical property called chirality. Scientists have long pondered why living things make use of only one version of certain molecules, such as the 'right-handed' form of the sugar ribose, which is the backbone of DNA. The discovery of propylene oxide in space boosts theories that chirality has cosmic origins. The scientists in the new study used radio telescopes to ferret out the chemical details of molecules in the distant, star-forming cloud of gas and dust. As molecules move around in the vacuum of space they emit telltale vibrations that appear as distinctive radio waves. Future studies of how polarized light interacts with the molecules may reveal if one version of propylene oxide dominates in space, the researchers said.
This discussion has been archived. No new comments can be posted.

Asymmetric Molecule, Key To Life, Detected In Space For First Time

Comments Filter:
  • by Anonymous Coward on Wednesday June 15, 2016 @02:15AM (#52320719)

    When I first read this, I thought they had found a non-50:50 ratio of enantiomers, but it appears that they have simply detected the presence of propylene oxide in some form, which doesn't seem terribly surprising to me. It would be fascinating if they did discover that one enantiomer was favoured but I'm not sure how this could be done short of collecting the chemical... are there any convenient sources of polarised light in space?

    • Re: (Score:1, Informative)

      by Anonymous Coward

      They look at light coming from the source. If there is any chirality, then the light is polarized into one plane and that plane is rotated 90 degrees left or right to the direction of the light.

      "In 1813 Jean Baptiste Biot noticed that plane-polarized light was rotated either to the right or the left when it passed through single crystals of quartz or aqueous solutions of tartaric acid or sugar. Because they interact with light, substances that can rotate plane-polarized light are said to be optically active

    • TFA was not that long....
      The complex signals tied to propylene oxide were not precise enough for the researchers to determine whether the molecules were orientated to the left or to the right.

      Like a hand's shadow, "it's impossible to tell if the left or the right hand is casting the shadow," said California Institute of Technology chemistry graduate student Brandon Carroll.

  • So Drake was right after all. There is life everywhere.
  • It's gone a long way in 6000 years.

    • by Empiric ( 675968 )
      Jesus said, "It is to those who are worthy of my mysteries that I tell my mysteries. Do not let your left (hand) know what your right (hand) is doing."

      --Thomas
  • by sugar and acid ( 88555 ) on Wednesday June 15, 2016 @03:53AM (#52320889)

    They've found that one of the simplest pair of chiral molecules can be created in space. Not surprising, and both the left and right enantiomers (the left and right handed molecules) are almost certainly present in a 50/50 ratio, so not enantiomerically pure. They have not shown anything at all interesting here.

    One of the defining things about chiral chemistry is that to have a pure enantiomeric compound you either have to start with an enantiomerically pure compound as a starting materials (biologically derived materials are the only known natural source) or have it interact with another enantiomericially pure catalyst (biological enzymes being the only known natural source of these) or purification medium. It is pretty much a signature of biology.

      What would be interesting is if there was found a chiral molecule in space that was significantly biased to one enantiomer. Depending on the context of what was found this would be proof of either extraterrestrial life, or a cosmic enantiomeric enrichment process that would have huge implications for understanding the origin of life.

    • by Dcnjoe60 ( 682885 ) on Wednesday June 15, 2016 @09:02AM (#52321791)

      What would be interesting is if there was found a chiral molecule in space that was significantly biased to one enantiomer. Depending on the context of what was found this would be proof of either extraterrestrial life, or a cosmic enantiomeric enrichment process that would have huge implications for understanding the origin of life.

      It would most certainly not be proof of either extraterrestrial life. It would only prove that there is some process going on in space producing a biased enantiomer. Could life be the process doing it? Yes, but unless we are claiming to know everything that occurs at the center of the galaxy where these enantiomers have been found, it would not be scientifically valid to claim it as proof of life.

      As for an enantiomeric enrichment process and the implication for understanding the origin of life, that too is pretty far fetched. It could help explain why there is a bias such as the immense gravitational fields, or heat or radiation or any number of things known and unknown. But, whatever that cause is, it would need to be determined if the bias had been the other way, would it had prohibited the formation of life? In otherwords, do all of our enantiomer exist in their current direction because the other direction would not be conducive to life (as we know it) or do they exist in their current direction because they are just made up of what happened to be the dominant version?

      If the answer of that question is the former, then there may be huge implications for understanding the origin of life. But only if we could determine what caused the bias in the beginning and whether or not that force still exists or the bias seen now is just an artifact (replicating molecules tend to replicate in the same pattern).

      • Re: (Score:2, Funny)

        by Anonymous Coward

        did you just take three paragraphs to say the exact same thing GP said in one sentence?

        Depending on the context of what was found this would be proof of either extraterrestrial life, or a cosmic enantiomeric enrichment process that would have huge implications for understanding the origin of life.

        You must be a social science major.

  • by robi5 ( 1261542 ) on Wednesday June 15, 2016 @04:08AM (#52320905)

    The news is interesting not so much for its contents, but for its illumination of a gap in my knowledge. I'm nowhere near astronomy, so I didn't know that in the past we were _not_ aware of the presence of asymmetric molecules in space. If someone asked, I'd have responded, "sure there are probably asymmetric molecules in space, why not" so in some sense, I might have given a more correct answer than someone who knew more about space. The downside is that when you not only learn from a piece of news, but it highlights a gap in your understanding before, then it's quite humbling. It's a bit like waking up in Vegas, and you're told you divorced while you were drunk, yet you aren't aware of getting married in the first place.

    • It's a bit like waking up in Vegas, and you're told you divorced while you were drunk, yet you aren't aware of getting married in the first place.

      Oh no, not another one of those nights....

      Origin of life? Man, how about the origin of what the hell happened last night?

  • From freshman chemistry class I keep hearing this "mirror image" molecules, and only one form is found in anything biological and it is very strange. As far as chemical reactions go, both left handed and right handed forms work equally well. I even remember a puzzler from Discover magazine, where the answer was, "take a biopsy sample of the alleged alien life form and check if it is the right handed or left handed version of the molecule. 50% chance you will get a definite answer".

    While biologists are fin

  • Has anyone else read the Expanse series and thought of the protomolecule when they read this?

  • One has to be careful with wording. Dextrorotatory ("right-handed") forms of various amino acids do occur in various roles in living organisms, just not commonly in protein synthesis.
    http://www.ncbi.nlm.nih.gov/pm... [nih.gov]
    http://www.ncbi.nlm.nih.gov/pm... [nih.gov]
  • by LeDopore ( 898286 ) on Wednesday June 15, 2016 @07:23AM (#52321349) Homepage Journal

    TFA suggests a beautiful idea: that life bears the imprint of handedness derived from cosmic dust. The idea may be beautiful, but it's wrong. It's much more likely that the chirality of biomolecules we see on Earth came from spontaneous symmetry breaking on Earth itself than by space seeding any preferred chirality.

    Complex molecules in living beings are assembled from consistent smaller molecules, known as monomers. Some of these monomers have a handedness (they have two enantiomers), and in that case living things will almost always use just one of the enantiomers. The best explanation for why living things tend to use just one enantiomer is the same reason you would hate to have two slightly different kinds of Lego blocks with incompatible pitch: this diversity usually just gets in the way of assembling complex macromolecules without providing any compelling value.

    Thus, we know even given no seeding of chirality from space, life would pick one chirality since having just one is usually useful. Add to that the facts that we haven't yet found a non-racemic mixture of anything in space, and that even if we did the fraction of space-derived non-racemic molecules on the Earth's surface would hardly noticeably change the balance of chiralities found in proto-life Earth, and it's pretty clear that the chirality of biomolecules in living things is totally independent of biased enantiomers from space.
     

    • Excellent explanation! I've had trouble explaining this before, but the Lego explanation should have legs with lay people.
    • There have been theories for some years that explain the preferred chirality of biological molecules (the ones which are chiral) because of the inherent asymmetry of the weak nuclear force. I've seen arguments that because of the weak force one enantiomer of a chiral molecule will be very slightly more tightly bound than the other and then due to biological selection (as you describe) and amplifying feedback effects during the rise of the first set biological molecules that the chirality we see today was p

      • I've seen this work too, and I don't buy it. The effects are far too subtle to influence chemistry enough for life to care. Once one chirality started getting used by an early microbe, there's no compelling reason to start experimenting with the other, and the chances that the weak force's minuscule influence had any significant influence on which enantiomer was chosen are pretty much nil.

  • Scientists have long pondered why living things make use of only one version of certain molecules, such as the 'right-handed' form of the sugar ribose, which is the backbone of DNA.

    The left-handed version of the sugar ribose (and other things) is used in the mirror [wikipedia.org] universe where the evil versions of ourselves are - Kirk and Dr. McCoy know what I'm talking about.

  • Does this mean that the yin-yang symbol must be drawn slightly differently?

Just go with the flow control, roll with the crunches, and, when you get a prompt, type like hell.

Working...