Occasionally I’ll wake up from a dream and have a question that will make me think: Fascinating question, I’ll have to ask the Dope. Only to find in the morning that it is really quite dull. However, after waking up this morning I thought that the question was still interesting. I too often phrase these poorly and someone comes in and accuses me of having English as a second language or something, so let me see if I can do it right this time:
If all the conditions that were on earth when life began were also in some place that lacked gravity, could “life” have happened? Is there anything in “life” that requires gravity?
Well… the very existence of both the Earth and the Sun requires gravity (to hold them together)… so a universe lacking gravity seems like a complete non-starter to me regarding the emergence of life (or anything more than single particles, for that matter)
Without gravity the sun wouldn’t work and stars wouldn’t form. The universe would be made up of hydrogen and helium because no heavier elements would form.
Am I right?
I think the first two answers are correct, and that a universe without gravity would be extremely thin cold gas getting thinner and colder. There’d be nothing bigger or more complicated than an atom or maybe a Hydrogen molecule.
If you want to posit a more synthetic setup, like a sterile chamber on a floating spacecraft that has various complicated chemicals and sunlight and warmth like early or present Earth, and maybe electrical discharges or other stimuli that people suspect of helping start life, I don’t think there’s anything prohibitive about the 0 g environment, but am not sure.
This is where I always get into trouble - not being precise enough.
We can assume gravity for the sun. I guess I’m thinking: if all the things that were required were somehow in a container in space - but still exposed to sunlight - would we be able to see life emerge? (On preview - I think **Napier **sums it up)
I think the question the OP is proposing is more along the lines of “Could life arise in a locally zero-G environment?” rather than “Could life arise in a zero-g universe?”. In that case you probably need something like Niven’s “Smoke Ring”. That is a vapour-air toroid constrained by nearby massive objects, as opposed to an atmosphere/ocean on the surface of a planet. I’ve no idea what the possibility of such a system arising with Earthlike temperature, air pressure, and primordial composition, but if abiogenesis is possible anywhere, I suppose it would be as possible there as here.
The only big thing I can think of that gravity does for prebiotic mixtures is speed the concentration of low density material like fatty acids at air/water interfaces. Without gravity the process would be slower, driven only by hydrophobic effects, but it’d still happen.
That might slow down the development of membranes/micelles which are necessary for life to develop. Of course, those membranes might also have arisen through interactions at the surface of clay particles, in which case the absence of gravity might would have little effect.
Everything else about life happens on such a small scale that electrostatic forces dominate gravity.
According to current theoretical physics thinking, gravity seems to be an inherent part of mass. Thus if something exists as matter, it exerts a gravitational attraction toward other matter.
Thus to say like the OP does “some place that lacked gravity” means that it also lacks mass, or matter. So not even the lightest elements could exist.
Obviously the problem with questions like this and cube earth are the fact that you have to determine which parts of reality you are going to accept. Even if we were to accept that complex matter exists without gravity. Even if we were to accept that planets exist somehow. There would be no atmosphere because nothing holds it in. Without an atmosphere you certainly have no oceans.
So if we then accept that planets, the atmosphere and oceans exist due to some other phenomenon we end up with an answer like Squink had proposed. I would even go so far as to say that chemical reactions are essentially unaffected by gravity. As squink mentioned there would not be concentration of denser material at the base, but this might actually increase the soluble ions by not allowing concentrated layers to develop on top of the ocean floor. Molecules that form miscelles will concentrate at the edges of the oceans (ocean floor, ocean surface, and shorelines) not because of gravity, but because of their hydrophobicity.
Of course some theories of abiogenesis suggest that hydrothermal vents are necesary for life to develop. Without gravity, there would be no volcanic activity.
Almost certainly. The Miller-Urey experiment demonstrates that life in a jar, given the right ingredients, is obscenely easy. As long as the hypothetical container has enough density and energy, organic compounds and eventually life will form, independent of gravity.
There is no factual answer to this questions, it’s pure guesswork.
No, and no.
The Miller-Urey experiment is interestng but it didn’t produce life, it didn’t produce anything remotely like life and Stanley Miller himself is quite open in admitting that it never could possibly poduce life.
So it in no way demonstrates that generating life is obscenely easy.
And it in no way demonstrates that life will eventually form. The fact is that the Miller-Urey apparatus, and indeed all hypothetical pre-biotic environments, suffer from the same flaw: complex organic molecules are destroyed far faster than they are created. IOW given enough time and energy the systems will never produce more than trace amounts of organic materials and never produce life.
And that is the problem with trying to answer the question. We have absolutely no idea how life came to be and as such it is imposisble to say what role gravity plays. Life may well be totally impossible in a gravity free environment. Then again it may be that gravity was a major impediment to the generation of life and that the whole process occurs much faster and much more regularly without it.
In a nutshell it demonstarted that you could get molecules associated with life from simple inorganic mixes in the right conditions. The original produces amino acids, later modifications producef other molecules including fatty acids. That’s pretty significant by itself since until then there was a conception that you couldn’t even get the basic stuff without pre-existing life.
The reason it could never have produced life is that the rate that the amino acids joined together was far slower than than the rate at which they were being destroyed. The entire atmosphere was inhospitable to complex organic molecules. If we assume that it would take a million years on average for a functional protein to form we run into the problem that any protein would be destroyed within 15 minutes. IOW there is simply no chance of any molecule hanging around long enough to become functional much less reproducing. Of course the entire setup was never desigend to produce life, or even mimic a primitive atmosphere very well. It was done to show that under some conceiveable circumstances we can get organic molecules without pre-existing life.
The big probelm is that to join monomers together you either need alot of energy or very reactive and unstable monomers, yet polymers are far less stable than monomers. So if you have alot of energy availble then that energy will rattle the polymers to pieces far more rapidly than it joins them together. It’s like trying to construct a lego castle by throwing the blocks into a cement mixer. If you’ve got enough energy to join even two blocks together then you have far enough energy to smash them apart more rapidly. And if you have reactive monomers then they will be reacting with evreything, nocluding the water itself, and the chances more than two of them ever existinglong enough to joing is effectively nil. Then we have the problem that Miller himself has often pointed out, which is that even under ideal circumstances the rate at which molecules would be put through boiling volcanic vents or destroyed by meteor impacts was far more frequent than the rate at which they could possibly be created.
So it remains a massive mystery.
We simply have no hypotheses that are even vaguely plausible about how life came to be. The hypothesis that life came from outer space is considered at least as strong a contender as any hypothesis of autochthonous development. That says a lot for the state of abiogenesis as a science.
This is almost entirely wrong. Anybody familiar with recent work by Kobayashi knows that simple surfactants can catalyze the formation of amide linkages in water. No reactive intermediates or high temperatures required. Polymers are less stable than monomers? Can we get a cite for this? If you’ve ever done any chemistry you would know that polymers are what form when you let your reaction get to hot. Under the right conditions you can’t stop polymers from forming, and its nothing like throwing leggos into a cement mixer. You are obviously not familiar with the concept of molecular self-assembly. Its a very hot topic these days because molecules do it all the time. Peter Stang does an excellent job of designing systems that spontaneously form ordered complexes. Miller is just plain wrong on this.
