Interstellar travel?

[Hrothbern]

It looks like that all life we know today, (the two prokaryotes Archaea, Bacteria and the Eukaryotes) makes use of the same subset of 23 proteins.
These 23 proteins catalyse the same very basic processes.
It could be that this comes also from convergent evolution. Meaning that different common ancestors evolved the same (optimal) proteins for the same features.
But that chance is very low, indicating all life we know today, exists today, has probably a common ancestor.

The oldest fossils we have found so far are BTW dated between 3.77-4.22 billion years ago (Canada, Hudson Bay, Nuvvuagittuq)
This leaves wide open that there could have been an essential and short window at that time for the origin of life, if the special circumstances at that time disappeared because of the end of the bombardments and in general the geological stage of the Earth at that time.

 

[Thorgalaeg]

Interesting stuff. Stellar material from before planetary formation left unheated is full of organic material. Sounds like The Integral Trees might be history instead of science fiction.

Thanks for pointing to something interesting.

It is really interesting. I wonder why the Milller experiment is so famous but these meteorites are relatively unknown.

 

[Berzerker]

In fact Murchison meteorite is a kind of meteorites supposed to be older than Earth itself.

From the link:

The meteorite belongs to the CM group of carbonaceous chondrites (see meteorite classification). Like most CM chondrites, Murchison is petrologic type 2, which means that it experienced extensive alteration by water-rich fluids on its parent body[2] before falling to Earth.

The Earth was - and is - a water rich body. The Earth's age is estimated based on meteorite ages since the early Earth didn't produce (many) rocks that survived the late heavy bombardment and plate tectonics. But the 'rocks' we do have - zircon crystals - formed in water and the oldest so far are in the 4.3 byo range. The Moon forming impact supposedly happened around 4.45 bya and there is evidence the Earth had water even then.

It seems rock formed as dust particles stuck to each other via static electricity and possibly the eddies within the solar magnetic field followed by lightning that melted and solidified the material. Gravity took over and built planetismals and finally planets via accretion.

 

[Timsup2nothin]

It is really interesting. I wonder why the Milller experiment is so famous but these meteorites are relatively unknown.

My complaint about the Miller experiment is that it stopped too soon. Rather than drying out the organic material to identify what it contained (okay, I'd have done that too, but on a second run...) they should have just kept it running until something came to life and broke loose. I think that the fact you never see any reports on that experiment indicate that it didn't go as hoped (create life) rather than reflecting that no one tried it.

 

[Hrothbern]

My complaint about the Miller experiment is that it stopped too soon. Rather than drying out the organic material to identify what it contained (okay, I'd have done that too, but on a second run...) they should have just kept it running until something came to life and broke loose. I think that the fact you never see any reports on that experiment indicate that it didn't go as hoped (create life) rather than reflecting that no one tried it.

The Miller experiment did not deliver the building blocks for RNA or DNA, the nucleotides.

 

[Timsup2nothin]

The Miller experiment did not deliver the building blocks for RNA or DNA, the nucleotides.

No matter how long it ran? I'd still be perking that muck if I were him...and not dead.

 

[Berzerker]

yeah, I'm skeptical a lab experiment on a short term basis could duplicate pre-life conditions

A recent docu on the Earth speculated life began as massive tides concentrated the necessary ingredients in layers over eons.

 

[Hrothbern]

No matter how long it ran? I'd still be perking that muck if I were him...and not dead.

No chance at all: nucleotides formation need a reducing environment. And the Miller test was in a neutral environment (as most likely the Earth atmosphere was as well).

 

[Timsup2nothin]

yeah, I'm skeptical a lab experiment on a short term basis could duplicate pre-life conditions

A recent docu on the Earth speculated life began as massive tides concentrated the necessary ingredients in layers over eons.

That brings to mind a science fiction proposition, in which life on earth was actually unique...a product of a one in a zillion confluence of the earth to single moon mass ratios and orbital length producing exactly the right tidal engine to properly stir the soup.

 

[Timsup2nothin]

No chance at all: nucleotides formation need a reducing environment. And the Miller test was in a neutral environment (as most likely the Earth atmosphere was as well).

So introduce oxygen. I wouldn't care if it was "cheating," and so long as it worked I doubt that anyone else would either. Come up with a process to cook up self replicating protein strands and whether it's accurate 'primal earth' or not it makes 19 pages of dispute moot.

 

[Hrothbern]

Perhaps good to throw in the pond of all considerations:
chemical processes need energy and some quite a lot.
making nucleotides, making ATP or predecessors, cost a lot of energy.

So you need temperature and either biochemical catalysts. Normally proteins but RNA/DNA can have calytic propereties as well.
Or you need temperature and other catalysts like the surface of anorganic materials.
Experiments done in simulated hot earth cracks with organic materials "attached" to clay, have resulted in results that look similar to parts and properties of living cells.

 

[Thorgalaeg]

Mother nature always prefers the refined ways of kinetics, with catalyzers, surface reactions and that sort of weird things. It is really complicated. Chemists prefer the bunsen burner way.

 

[Hrothbern]

So introduce oxygen. I wouldn't care if it was "cheating," and so long as it worked I doubt that anyone else would either. Come up with a process to cook up self replicating protein strands and whether it's accurate 'primal earth' or not it makes 19 pages of dispute moot.

With enough food, which there was in the beginning, the key elements are: replicating, catalyst action and some kind of membrane to lock the toolkit together.
Food: If somewhere on Earth, in some hot ocean vulcanic crack, the circumstance were perfect for generating nucleotides, and another spot perfect for converting those to nonsense RNA, we would have a supply of nucleotides.
Food: If somewhere else the circumstances were optimal for generating amino acids. Great. And if some circumstances would favor some di-peptides or smaller multi-peptides. Fantastic.
Food ?: The last one, the membranes is tricky. The most primitive bacteria, the Archaea, do not use fatty acids to make their cell membranes. They miss one protein needed to make them as all other life makes them. And that probably means that the ocean soup did not have many fatty acids and the first life forms were without cell membranes to keep their toolkit together, and needed clay pores or so to have everything nearby, until they could code for the proteins to catalyse the generation of fatty acids.

Once you have random nonsense RNA, in an adequate pool of food, it is waiting for a random that does code for something that enhances the duplication of that RNA.
That could go extremely primitive.
Once that RNA is there it only needs a further random to favor certain small proteins that enhance further duplication rate.
Many, many random small steps.
I think that both the tests as the simulations are being done.
The investigation of common chartacteristics of living organisms is part of that (those 23 base proteins, and ofc also those "only" 20 amino acids).
Because the less components Real Life used, the less ingredients are needed in our RL tests and simulations.

There are people that believe that proteins were the first duplicating machines, but RNA does it already in very short chains and proteins can only duplicate when their catalyst spot favors their own amino acid composition.
So I do not believe that.

 

[Thorgalaeg]

With enough food, which there was in the beginning, the key elements are: replicating, catalyst action and some kind of membrane to lock the toolkit together.
Food: If somewhere on Earth, in some hot ocean vulcanic crack, the circumstance were perfect for generating nucleotides, and another spot perfect for converting those to nonsense RNA, we would have a supply of nucleotides.
Food: If somewhere else the circumstances were optimal for generating amino acids. Great. And if some circumstances would favor some di-peptides or smaller multi-peptides. Fantastic.
Food ?: The last one, the membranes is tricky. The most primitive bacteria, the Archaea, do not use fatty acids to make their cell membranes. They miss one protein needed to make them as all other life makes them. And that probably means that the ocean soup did not have many fatty acids and the first life forms were without cell membranes to keep their toolkit together, and needed clay pores or so to have everything nearby, until they could code for the proteins to catalyse the generation of fatty acids.

Once you have random nonsense RNA, in an adequate pool of food, it is waiting for a random that does code for something that enhances the duplication of that RNA.
That could go extremely primitive.
Once that RNA is there it only needs a further random to favor certain small proteins that enhance further duplication rate.
Many, many random small steps.
I think that both the tests as the simulations are being done.
The investigation of common chartacteristics of living organisms is part of that (those 23 base proteins, and ofc also those "only" 20 amino acids).
Because the less components Real Life used, the less ingredients are needed in our RL tests and simulations.

There are people that believe that proteins were the first duplicating machines, but RNA does it already in very short chains and proteins can only duplicate when their catalyst spot favors their own amino acid composition.
So I do not believe that.

The membrane probably was the first thing. You only need some heat and very basic organic compounds to get fatty acids, and fatty acids can spontaneously form a lipid bilayer, so basically a cell memabrane. Probably the sea was full of little fatty bubbles, many empty and many containing amino acids and nucleotides or at least nitrogenous bases.

 

[Hrothbern]

The membrane probably was the first thing. You only need some heat and very basic organic compounds to get fatty acids, and fatty acids can spontaneously form a lipid bilayer, so basically a cell memabrane. Probably the sea was full of little fatty bubbles, many empty and many containing amino acids and nucleotides or at least nitrogenous bases.

I dig into that
What I knew I said in that post: that the oldest/most primitive life form the Archaea cannot make the cell membrane fatty acids and are also not using them (independent factors as such).
And bacteria are far more enhanced: they can even change the average lenghth and isomers of the fatty acids of their cell membranes as function of the temperature they live in.
(which make sense becauise you need a certain viscosity range of your membrane and that means that adapting to temperature changes is an advantage)

I dig in

 

[Hrothbern]

On that self replicating RNA I tried to find some stuff that gives the up to date status
It has been done in a lab test but it needs in that experiment two strands that work together.
https://www.sciencedaily.com/releases/2009/01/090109173205.htm

Ultimately, this process enabled the team to isolate an evolved version of the original enzyme that is a very efficient replicator, something that many research groups, including Joyce's, had struggled for years to obtain. The improved enzyme fulfilled the primary goal of being able to undergo perpetual replication. "It kind of blew me away," says Lincoln.

The replicating system actually involves two enzymes, each composed of two subunits and each functioning as a catalyst that assembles the other. The replication process is cyclic, in that the first enzyme binds the two subunits that comprise the second enzyme and joins them to make a new copy of the second enzyme; while the second enzyme similarly binds and joins the two subunits that comprise the first enzyme. In this way the two enzymes assemble each other — what is termed cross-replication. To make the process proceed indefinitely requires only a small starting amount of the two enzymes and a steady supply of the subunits.

"This is the only case outside biology where molecular information has been immortalized," says Joyce.

 

[Berzerker]

No chance at all: nucleotides formation need a reducing environment. And the Miller test was in a neutral environment (as most likely the Earth atmosphere was as well).

I googled reducing environment and they talked about removing oxygen from a system. Is that about right? The theory I saw on TV said tides continually built up a layer of stuff concentrating the right ingredients on land so tidal ponds were a likely source for life. I guess the pond 'scum' literally gave rise to life...according to the theory anyway. The repeated saturation and drying of stuff, maybe in clay, was how life began. Thats interesting, that would mean we had to have land for life. Wouldn't need to be a continent like today, but something above water for at least part of the day that could survive the tides. You mentioned volcanic vents as a possibility, if thats the case land isn't even needed and Europa could harbor life.

 

[Hrothbern]

I googled reducing environment and they talked about removing oxygen from a system. Is that about right?

decreasing oxygen or increasing hydrogen is reducing.
(reductor vs oxidator)

The theory I saw on TV said tides continually built up a layer of stuff concentrating the right ingredients on land so tidal ponds were a likely source for life. I guess the pond 'scum' literally gave rise to life...according to the theory anyway. The repeated saturation and drying of stuff, maybe in clay, was how life began. Thats interesting, that would mean we had to have land for life. Wouldn't need to be a continent like today, but something above water for at least part of the day that could survive the tides. You mentioned volcanic vents as a possibility, if thats the case land isn't even needed and Europa could harbor life.

It looks like clay is important
Clay near a volcanic crack both hot (catalyst) and having metals (catalyst) and having surface (cartalyst) and having compartments (keep the toolkit together).

And if life did indeed evolve around 4 billion years ago.... at that moment the tectonic process, creating our landmasses, had hardly started.
So perhaps most of that clay was pulverised meteorites.

Here a vid starting 3.3 billion years ago:

 

[Berzerker]

that was so cool...and soothing. I gotta watch it again, I lost track of the continents colors

 

[Timsup2nothin]

that was so cool...and soothing. I gotta watch it again, I lost track of the continents colors

Lava lamp, hipster.