by 0x000xca0xfe
18 subcomments
One longstanding theory is that life first began on Earth when asteroids carrying fundamental elements crashed into our planet long ago.
I'm no expert but this sounds strange. Surely those fundamental elements would also form in vast quantities on their own on an entire planet with volcanoes and oceans? Wouldn't a couple asteroids be the literal drop in the ocean in comparison?The missing part is how do they form self-replicating mechanisms capable of evolution. I doubt an asteroid with a bit of organic dust is enough for that. If such small amounts suffice we should see the formation of new life forms from scratch, today, left and right I think?
by Amorymeltzer
1 subcomments
- I'm in the middle of reading Peter Brannen's The Story of CO2 Is the Story of Everything—it's excellent and goes deep into the (bio)geochemistry of Earth—and he presents a good case for a metabolism-first development of life, taking advantage of "a disequilibrium that needed to be relieved at the vents, an unending stream d free energy to dissipate," rather than the RNA information-first theories.
It fits his overall narrative but it was an interesting way to think about life "as a thermodynamically necessary mechanism to relieve the continuous production of free geochemical energy on Earth... more efficiently than abiotic processes could." (Brannen quoting complex-systems scientist Anne-Marie Grisogono) I highly recommend the book.
- It contains nucleobases. But does it contain ribose, or ribose linked to the nucleobases, or to phosphates? And more generally, does it also contain a grab bag of related chemicals that are not building blocks? The existence of such blocks as minor constituents of a soup of random chemicals doesn't mean much, especially as the concentration of any such constituent declines exponentially with its complexity.
- I wonder how they prevent contamination of the containers used to collect and store samples.
I assume they have to be ultra clean in every sense of the word 'clean' with the cavity pulled to a vacuum. And also the equipment that collects the sample and puts it into the canister has to be clean as well.
The logistics aren't obvious to me at all
by stevenjgarner
1 subcomments
- Ummm ... the "Victoria University of Wellington in Australia"? Please. Victoria University is located in Wellington, New Zealand [1]. Nothing to do with Australia. Dr. Morgan Cable is a Senior Lecturer in Space Science at Te Herenga Waka, Victoria University of Wellington in New Zealand [2]. Can't believe that phys.org would publish such an error.
[1] https://www.wgtn.ac.nz/
[2] https://www.psi.edu/staff/profile/morgan-cable/
by Shitty-kitty
0 subcomment
- The most important question we all want answered is just how rare life is in the Universe.
The fact that the building blocks are there just floating around on asteroids makes it that much more likely that its quite common.
- If you look at the paper, the nucleobases were present at concentrations of about 1 nanomole per gram. So, maybe 200 ppb by mass for each. They are in a sea of other random organic stuff that is at best tangentially relevant to life as we know it.
- Are these building blocks not evaporated on impact?
by hmokiguess
2 subcomments
- How are samples collected? In space or as debris?
- So what?! This does not prove anything! There are stones all around us, but they don't assemble themselves into beautiful, majestic stone buildings! All ingredients of concrete are around us, but we don't see them turning into concrete and pouring themselves into freeways, bridges, and all kinds of much less complex than living organisms!
- Fred Hoyle suggested this back in the seventies and eighties and was berated for it.
by shevy-java
2 subcomments
- That's not really new. It seems as if some people try to project "there is life outside of planet Earth". Well, the thing is ... is this question important? You already have life here. Synthetic biology will also progress. So why is it important if life is anywhere else? I don't understand it.
There is nothing magic in RNA or DNA. Granted, right now we can not easily explain how life gets "bootstrapped", but recently there was a paper of self-propagating RNA even of a kind of semi-random sequence; this RNA can just amplify itself. I am sure you can find many more similar examples eventually as well as biochemical reaction processes that can be "bootstrapped" - and I am also sure none of these work on an asteroid. So why is there this strange focus on "life outside of planet Earth"? Some people want research money, that is clear now.
- Doesn't multi-world interpretation pretty much answer how life originated?
I mean, even if the starting state require to bootstrap life have impossibly low chance to happen random, multi-world interpretation implies that there will be some worlds where it happened, and observation of life is only possible in such worlds..
by brcmthrowaway
2 subcomments
- Anyone else think a universal intelligence is behind seeding planets with these rocks?
- I’ve wondered before if the idea that life originated on Earth might be the last geocentrism to fall.
Speculation of course, but it would fit a certain historical pattern.
Maybe life is all over the damn place, just a thing that happens under certain thermodynamic constraints, and it arrived on board comets or some similar mechanism.
Maybe space contains spores of minimal super simple organisms that can survive being vacuum freeze dried for incredibly long periods of time. When they land somewhere suitable they do stuff.
Maybe life originated long, long ago. The wildest speculation I have is that it originated shortly after the big bang during a brief period when the temperature of the universe was temperate, but that’s very far fetched for numerous reasons. More likely that it pops up from time to time and spreads over cosmic time scales.
But it only evolves to high levels of complexity in environments that are very friendly to a lot of life, have abundant energy, and are stable enough for a very long time. That may be the rare thing.
by johnsmalles
2 subcomments
- Fascinating that all five nucleobases were found in Ryugu samples. The fact that these formed abiotically in an asteroid environment strengthens the case that the building blocks of life are common throughout the solar system. The amino acid findings from the same samples were already compelling, but having the complete nucleobase set is a different level of evidence.
by zenon_paradox
0 subcomment
- [dead]
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