Deep beneath earth's surface, clues to life's origins • Hacker News Board

Re: Deep beneath earth's surface, clues to life's origins

#11

Post by syllablehq » Sun, Jan 07, 2024, 5:26 PM UTC

orangepinyata wrote: post #4

olddustytrail wrote: post #2

This is something I wondered about the idea of life beginning in the oceans and spreading to dry land. If approximately 70 percent of the total number of microbes on the planet live underground today (number I googled) wouldn't it make more sense that life began underground and slowly spread to the surface? Is this a theory anywhere?

It's an interesting suggestion but I think given what we know of life it's unlikely. I guess (obviously this is all speculation - none of us were there!) the origin of life can sort of be thought of as going from chemistry/geochemistry to biochemistry. And purely from a rate of reactions perspective, in a nice solvent like water that's likely to be more conducive to the origin of life than deep underground (in solids…

I posted another comment above about recent discoveries that the Earth has enormous quantities of hydrogen deep underground which is constantly bubbling to the surface - and in fact, flowing all the way up to the upper atmosphere and even escaping into space (!). So this would indeed seem to provide a flux even deep underground. Understanding this geologic hydrogen cycle is a fascinating new field.

Re: Deep beneath earth's surface, clues to life's origins

#12

Post by orangepinyata » Sun, Jan 07, 2024, 5:31 PM UTC

freedomben wrote: post #8

orangepinyata wrote: post #4

Earlier quoted context omitted.

It's an interesting suggestion but I think given what we know of life it's unlikely. I guess (obviously this is all speculation - none of us were there!) the origin of life can sort of be thought of as going from chemistry/geochemistry to biochemistry. And purely from a rate of reactions perspective, in a nice solvent like water that's likely to be more conducive to the origin of life than deep underground (in solids…

I bought "The Vital Question" last year, but haven't read it yet. I started "Oxygen" by the same author though and found it a real slog. It felt like it occupied a hard position, assuming a fair amount of relevant scientific background in the reader, and wasn't really a book meant for general consumption. It's definitely possible I just wasn't in the right mental state for it. Did you find his books to be like that?…

I'll admit I haven't read them that recently but from what I recall the Vital Question is slightly more readable than Oxygen. That said, all of his books are very 'thorough' in the sense that he's definitely posing them as trying to make an argument as opposed to just educational, which does definitely make them less readable than they could be. Less bedtime reading and more something to actually make time for I guess?

I have seen him give talks in person before and they've been a lot clearer - maybe there's some on youtube? He's been on a few of the 'In Our Time' podcast episodes, so they might be interesting too?

Re: Deep beneath earth's surface, clues to life's origins

#13

Post by ninkendo » Sun, Jan 07, 2024, 5:37 PM UTC

JoeAltmaier wrote: post #3

olddustytrail wrote: post #2

This is something I wondered about the idea of life beginning in the oceans and spreading to dry land. If approximately 70 percent of the total number of microbes on the planet live underground today (number I googled) wouldn't it make more sense that life began underground and slowly spread to the surface? Is this a theory anywhere?

I favor the idea that a planet with a moon in a slightly eccentric orbit (earth) you have oceans washing minerals over every grain of sand on every beach, depositing then washing away different concentrations of everything, wetting and drying and applying sunlight and shade, warming and cooling. A billion billion petri dishes over a billion years. Eventually bingo! organic molecules then life.

I don’t even think it’s the eccentricity that does it, all it matters is that the earth isn’t tidally locked with the moon, that’s what gives you the tides: Earth is rotating faster than the moon orbits and so different parts of the earth face the moon within a day. It also helps that the moon is a significant fraction of the mass of the earth, which means its gravitational influence is significant to the oceans.

Re: Deep beneath earth's surface, clues to life's origins

#14

Post by comboy » Sun, Jan 07, 2024, 5:37 PM UTC

olddustytrail wrote: post #2

This is something I wondered about the idea of life beginning in the oceans and spreading to dry land. If approximately 70 percent of the total number of microbes on the planet live underground today (number I googled) wouldn't it make more sense that life began underground and slowly spread to the surface? Is this a theory anywhere?

All life is made out of cells. All cells are filled with water. Phospholipids which make cells membrane arrange themselves into membrane because one part of them is hydrophobic and the other hydrophilic. Although I guess some water is present underground too.

Re: Deep beneath earth's surface, clues to life's origins

#15

Post by adrian_b » Sun, Jan 07, 2024, 5:52 PM UTC

olddustytrail wrote: post #2

This is something I wondered about the idea of life beginning in the oceans and spreading to dry land. If approximately 70 percent of the total number of microbes on the planet live underground today (number I googled) wouldn't it make more sense that life began underground and slowly spread to the surface? Is this a theory anywhere?

The essential ingredient for the origin of life is a source of energy.

The use of solar energy did not become possible until at least a few hundred million years after the appearance of life, perhaps only after more than a billion years, because the trans-membrane ionic pumps powered by solar light are extremely complex structures that could not have been created out of non-living substances.

The only known energy source that can cause the appearance of life is the reaction between dihydrogen (elemental hydrogen) and carbon monoxide or carbon dioxide. Carbon dioxide exists in huge quantities everywhere on any planet without living beings (Earth is an anomaly, because most of the original carbon dioxide has been reduced and incorporated in living matter), so what is necessary for the appearance of life is a source of free dihydrogen. A gradient of ionic concentration in water is also helpful.

Such conditions are present where either volcanic gases are released in water or in the so called alkaline vents, where rocks rich in iron are oxidized by water, releasing the hydrogen from water as dihydrogen (this is the "serpentinization" mentioned in the parent article).

Both kinds of conditions are more typical for certain places on the bottom of the ocean, but they can be also encountered under ground, with the condition that there must be water infiltrated through the rocks, without water there is no source of free dihydrogen.

Re: Deep beneath earth's surface, clues to life's origins

#16

Post by olddustytrail » Sun, Jan 07, 2024, 6:01 PM UTC

comboy wrote: post #14

olddustytrail wrote: post #2

This is something I wondered about the idea of life beginning in the oceans and spreading to dry land. If approximately 70 percent of the total number of microbes on the planet live underground today (number I googled) wouldn't it make more sense that life began underground and slowly spread to the surface? Is this a theory anywhere?

All life is made out of cells. All cells are filled with water. Phospholipids which make cells membrane arrange themselves into membrane because one part of them is hydrophobic and the other hydrophilic. Although I guess some water is present underground too.

Well that relates to something I heard a few years ago about there being more water in the earth's crust and mantle than in the oceans. Isn't there some SciFi book along those lines with the water rising up? Not something I've actually read, but I'm pretty sure I heard about it.

Re: Deep beneath earth's surface, clues to life's origins

#17

Post by pixl97 » Sun, Jan 07, 2024, 6:29 PM UTC

syllablehq wrote: post #10

Very cool research. On the topic of hydrogen deep underground: I'm not an expert, just a fascinated amateur, but I've been fascinated by the recent discovery that there is enormous amounts of hydrogen below the earth. In fact, this article mentions hydrogen forming by serpentinization, and says that the researchers were shocked to find so much hydrogen. Recent research indicates that hydrogen may exist deep in the ea…

If the Earth didn't have a huge internal geological reserve of hydrogen (and other gaseous chemicals) we'd effectively be a dead planet. It's easy to lose hydrogen to space, which is one reason we don't see much of it in the atmosphere. When we start talking about geologic timescales it would lead to the disassociation and lose of almost all atmospheric gasses. Luckily we have the tectonic plate cycle that puts new gasses in the atmosphere and kicks our eventual extinction down the road a bit farther. This also leads to earth shrinking over these very long time periods.

Re: Deep beneath earth's surface, clues to life's origins

#18

Post by adolph » Sun, Jan 07, 2024, 6:38 PM UTC

ninkendo wrote: post #13

JoeAltmaier wrote: post #3

Earlier quoted context omitted.

I favor the idea that a planet with a moon in a slightly eccentric orbit (earth) you have oceans washing minerals over every grain of sand on every beach, depositing then washing away different concentrations of everything, wetting and drying and applying sunlight and shade, warming and cooling. A billion billion petri dishes over a billion years. Eventually bingo! organic molecules then life.

I don’t even think it’s the eccentricity that does it, all it matters is that the earth isn’t tidally locked with the moon, that’s what gives you the tides: Earth is rotating faster than the moon orbits and so different parts of the earth face the moon within a day. It also helps that the moon is a significant fraction of the mass of the earth, which means its gravitational influence is significant to the oceans.

Eccentricities also contribute to long duration cycles of tides. Instead of all the Petri dishes following a single cycle, there is also another dimension of longer cycle dishes.

Re: Deep beneath earth's surface, clues to life's origins

#19

Post by jl6 » Sun, Jan 07, 2024, 6:56 PM UTC

syllablehq wrote: post #10

Very cool research. On the topic of hydrogen deep underground: I'm not an expert, just a fascinated amateur, but I've been fascinated by the recent discovery that there is enormous amounts of hydrogen below the earth. In fact, this article mentions hydrogen forming by serpentinization, and says that the researchers were shocked to find so much hydrogen. Recent research indicates that hydrogen may exist deep in the ea…

Let’s hope we don’t find and extract so much subterranean hydrogen that we burn it into water and cause sea level rise.

Re: Deep beneath earth's surface, clues to life's origins

#20

Post by queuebert » Sun, Jan 07, 2024, 7:07 PM UTC

olddustytrail wrote: post #16

comboy wrote: post #14

Earlier quoted context omitted.

All life is made out of cells. All cells are filled with water. Phospholipids which make cells membrane arrange themselves into membrane because one part of them is hydrophobic and the other hydrophilic. Although I guess some water is present underground too.

Well that relates to something I heard a few years ago about there being more water in the earth's crust and mantle than in the oceans. Isn't there some SciFi book along those lines with the water rising up? Not something I've actually read, but I'm pretty sure I heard about it.

The water exists in the rock mostly like water exists in the silica packets in everything you buy these days -- chemically bound in hydrated forms of crystals. That means it must be taken into account in any chemistry models, but not that there's a giant reservoir underground waiting to burst out in a flood.