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Protein discovered inside a meteorite

phys.org

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Re: Protein discovered inside a meteorite

#41

Post by undersuit »

qubex wrote: post #18
westmeal wrote: post #2

Proponents of panspermia are pretty happy about this finding I bet.

To be perfectly honest, you’ve drawn my attention to an ambiguity I had never before noticed: does panspermia’s hypothesis that “life” came from space require that life arrive fully formed and functional, or does it advocate that complex organic chemicals arrived from space and assembled on earth into a working configuration? I have always found the idea of panspermia to be a bit of a cop-out as it totally sidesteps…

I think a complex molecule could accepted. We don't know why our biological systems settled on their chirality, but maybe it was from a massive bump of molecules with all the same chirality from an extra-solar source.

https://en.wikipedia.org/wiki/Chirality_(chemistry)#In_bioch...

Re: Protein discovered inside a meteorite

#42

Post by shartshooter »

I read a comment on HN or Reddit a while back about how some molecules were found in a meteorite that were left-handed where every molecule on earth is right-handed or something to that extent.

If my memory serves it was as if molecules fit together like a lock and key except this molecule's key/lock combo was inverted.

Apologies if I'm bungling it up but it felt as though it was significant. As if the molecule found was unlike any molecule on earth due to its lock/key orientation.

Re: Protein discovered inside a meteorite

#43

Post by T-A »

VT_Dude wrote: post #30

Before we even get into the role of expert peer reviewers, does the article pass basic tests of authenticity, let alone extraordinary claims requiring extraordinary proof? The third author of the referenced paper does have a page at Harvard, here: http://www.people.fas.harvard.edu/~mcgeoch/index.html where she says she is at the "Department of Molecular and Cellular Biology, Harvard University" but she's not listed a…

You can look up McGeoch, Julie here:

https://www.directory.harvard.edu/

Associate of the Department of Molecular and Cellular Biology.

Previous papers on arxiv (just click the author name on the abstract page):

https://arxiv.org/search/astro-ph?searchtype=author&query=Mc...

I am all for healthy skepticism, but insinuating a hoax based on an ad hominem without even spending a few seconds to do a quick check is not.

Re: Protein discovered inside a meteorite

#44

Post by anorwell »

shartshooter wrote: post #42

I read a comment on HN or Reddit a while back about how some molecules were found in a meteorite that were left-handed where every molecule on earth is right-handed or something to that extent. If my memory serves it was as if molecules fit together like a lock and key except this molecule's key/lock combo was inverted. Apologies if I'm bungling it up but it felt as though it was significant. As if the molecule found…

I think the homochirality of amino acids might be what you're referring to:

https://en.wikipedia.org/wiki/Chirality_(chemistry)#In_bioch...

"The origin of this homochirality in biology is the subject of much debate.[12] Most scientists believe that Earth life's "choice" of chirality was purely random, and that if carbon-based life forms exist elsewhere in the universe, their chemistry could theoretically have opposite chirality. However, there is some suggestion that early amino acids could have formed in comet dust. In this case, circularly polarised radiation (which makes up 17% of stellar radiation) could have caused the selective destruction of one chirality of amino acids, leading to a selection bias which ultimately resulted in all life on Earth being homochiral."

Re: Protein discovered inside a meteorite

#45

Post by jleahy »

shartshooter wrote: post #42

I read a comment on HN or Reddit a while back about how some molecules were found in a meteorite that were left-handed where every molecule on earth is right-handed or something to that extent. If my memory serves it was as if molecules fit together like a lock and key except this molecule's key/lock combo was inverted. Apologies if I'm bungling it up but it felt as though it was significant. As if the molecule found…

You are talking about chirality. Biologically produced molecules are all of the same "handedness", but molecules produced by other means (normal chemical reactions) tend to have 50/50 chance to be either handedness (although selective reactions are possible).

So you'd expect to see both at a 50/50 ratio in a meteorite, if you see any at all. That's just chemistry.

Re: Protein discovered inside a meteorite

#46

Post by rolph »

jessaustin wrote: post #40
rolph wrote: post #6

A team of researchers from Plex Corporation, Bruker Scientific LLC and Harvard University > has found evidence of there is a mismatch between the title of that article and the level of confidence these researchers were expressing. the preprint is here: https://arxiv.org/abs/2002.11688

One of the cites at the link is a previous paper on similar investigations of one of the same meteorites plus one other, that was published in 2015 in Meteoritics & Planetary Science , a journal with a long publication history. That paper is cited by two other papers from different authors. [0] At some level, these researchers seem to be doing basic chemistry. Maybe they're not characterizing the implications correct…

this is proper research as depicted by the publications linked to ref. [0].

the origin of the elements composing the organic compounds is very likely non terrestrial as indicated by isotopic ratios.

the time and nature of the assembly of these compounds is not apparent.

assembly may have been primordial involving cometary CN and production of polyglycine.

assembly may have been metallo-organic catalysis, at any time from formation of the parent "rock" chondrite, upto the time circa. discovery

a biological process may have been involved with assembly, after impact of the meteoric subject with earth.

the suitability of this material for exploitation by chemolithotrophic organisms in the past should not be overlooked

Re: Protein discovered inside a meteorite

#47

Post by kens »

shartshooter wrote: post #42

I read a comment on HN or Reddit a while back about how some molecules were found in a meteorite that were left-handed where every molecule on earth is right-handed or something to that extent. If my memory serves it was as if molecules fit together like a lock and key except this molecule's key/lock combo was inverted. Apologies if I'm bungling it up but it felt as though it was significant. As if the molecule found…

Interestingly, the protein described in the article is made out of glycine, the only amino acid that doesn't have handedness (i.e. it is achiral). So you can't tell if this protein is terrestrial or not based on its handedness.

Re: Protein discovered inside a meteorite

#48

Post by rolph »

jessaustin wrote: post #40
rolph wrote: post #6

A team of researchers from Plex Corporation, Bruker Scientific LLC and Harvard University > has found evidence of there is a mismatch between the title of that article and the level of confidence these researchers were expressing. the preprint is here: https://arxiv.org/abs/2002.11688

One of the cites at the link is a previous paper on similar investigations of one of the same meteorites plus one other, that was published in 2015 in Meteoritics & Planetary Science , a journal with a long publication history. That paper is cited by two other papers from different authors. [0] At some level, these researchers seem to be doing basic chemistry. Maybe they're not characterizing the implications correct…

>> At some level, these researchers seem to be doing basic chemistry what it looks like to me is that a couple just received a good research grant set up a laboratory in started putting it to good use. we need to find these polymers on samples that are still off world, or we need to be able to demonstrate such polymerization in an environment mimmicking conditions off planet.

Re: Protein discovered inside a meteorite

#49

Post by lovemenot »

andrewflnr wrote: post #35
qubex wrote: post #18

Earlier quoted context omitted.

To be perfectly honest, you’ve drawn my attention to an ambiguity I had never before noticed: does panspermia’s hypothesis that “life” came from space require that life arrive fully formed and functional, or does it advocate that complex organic chemicals arrived from space and assembled on earth into a working configuration? I have always found the idea of panspermia to be a bit of a cop-out as it totally sidesteps…

A panspermia theory that involved non-living chemicals coming to Earth would be pretty useless. There's no real doubt that it's possible to generate those chemicals on Earth, and AFAIK it's still believed to be easier to make them on Earth than in space. Organic chemicals from space would just mix with all the ones that were already here.

>> it's still believed to be easier to make them on Earth than in space

I don't mean to be glib, but space is very large and time before our planet was formed is very long.

I assume that if it was easy here in those first few hundred million years, it had already been even easier in many elsewhere places. Any one, or multiples of which could have seeded us with as yet locally unavailable precursors and possibly even life.

Re: Protein discovered inside a meteorite

#50

Post by driverdan »

rolph wrote: post #6

A team of researchers from Plex Corporation, Bruker Scientific LLC and Harvard University > has found evidence of there is a mismatch between the title of that article and the level of confidence these researchers were expressing. the preprint is here: https://arxiv.org/abs/2002.11688

It's bad writing. They also have this gem:

> but once the findings are confirmed...

which should be "but if the findings are confirmed"

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