5 ms·
That omits what I consider to be a key part of the insight: that the conditions might no longer be able to give rise to new life because today existing organism
by mcherm 6y ago
That omits what I consider to be a key part of the insight: that the conditions might no longer be able to give rise to new life because today existing organisms would exploit the rich molecules before they had an opportunity to produce proto-living things.
- mannykannot 6y agoThat is very plausible, and it might even be the case that once free oxygen started building up in the atmosphere (from about 2.5 bn years ago, accelerating after 1 bn ya), the environment had become chemically unsuitable. Another consequence of free oxygen is the formation of an ozone layer, reducing the UV flux at the surface. I guess the significance of that depends on whether UV helped or hindered the process.
- libraryatnight 6y agohelped or hindered, does that mean there was basically a window of opportunity and life made it?
- mongol 6y agoPerhaps not in this particular example. Without the oxygen, a bi-product of life, no ozone and no limitation of UV radiation. However other windows of opportunity may have closed. Such as seems to have happened on Mars and Venus.
- nextaccountic 6y agoNote that the oxygen in atmosphere was created by life itself. Oxygen molecules are highly reactive and without a process that continually produces them they would eventually disappear.
- cblconfederate 6y agoWhat about Mirror Life? These wrong-handed molecules would be transparent to all existing life https://en.m.wikipedia.org/wiki/Mirror_life https://en.m.wikipedia.org/wiki/Mirror_life
- hannasanarion 6y agoProteins, DNA, and other life structures could be mirrored, but sunlight, minerals, water, and acids can't, and right-handed life has already monopolized them.
- cblconfederate 6y agoi think they can all be mirrored, naturally (light or water isn't chiral). none of them exists in one form more than the other
- gus_massa 6y ago"Transparent" is an exaggeration. If the mirror components were abundant, some bacteria would have learn to eat it, and we would have a chiral war. (Perhaps this happened, and we won!) For example from https://en.wikipedia.org/wiki/Amino_acid https://en.wikipedia.org/wiki/Amino_acid > These are all L-stereoisomers ("left-handed" isomers), although a few D-amino acids ("right-handed") occur in bacterial envelopes, as a neuromodulator (D-serine), and in some antibiotics. > Although D-isomers are uncommon in live organisms, gramicidin is a polypeptide made up from mixture of D- and L-amino acids. Other compounds containing D-amino acids are tyrocidine and valinomycin. Some bacteria can produce the D- version of the amino acids, and use them in peptides that are natural antibiotics because other bacteria don't know how to destroy them. (Anyway, some other bacteria can are resistant, because they developed a way to destroy them.)
- JuliusPullo 6y agoThis should be easy to observe. If this process of creation of rich-complex molecules is happening today, we should be able to find some of these "ponds" where bacteria feeds on newly created rich molecules. If this found, then we would know why every bit of life on earth today descends from one single common ancestor (Last universal common ancestor)--The more complex of the first lifeforms to exist simply ate every other that arose afterwards.
- gus_massa 6y agoThe efficiency of these reactions is much less than photosynthesis, so don't expect to find this now. Also, it probably requires an ambient with a lot of methane or some similar compound, but probably other bacteria are eating the methane, or oxygen is destroying it.