13.8 Billion years ago, the universe was created in a magical moment that we have yet to understand.
370,000 years after that, it cooled down enough to finally let protons bind to electrons, and the first atoms formed (99% hydrogen, 1% helium).
100M years after that, much of that hydrogen gas collapsed into stars, which underwent nuclear fusion to produce helium, carbon, nitrogen, oxygen, and other heavier elements up to iron. Some of those stars went supernova and released their enriched guts out into the universe.
After billions of years of that, we had enough heavier elements to form rocky planets, of which one is the planet we're on now.
Somehow on this wet rock, organic molecules formed and found ways to replicate themselves inside of membranes. A billion years after this wet rock came into existence, some of these replicating membranes bound to each other and started to act in harmony to ensure the continued replication of the whole group of membranes.
For another billion years, these groups of self-replicating membranes got larger and more complex. Eventually, one of them grew opposable thumbs, a large brain, and started to make tools. Those hairy apes, my ancestors, against all odds, for millions of years, fought against wolves, tigers, the elements, starvation, and each other to form an unbroken lineage that led to the existence of my parents.
36 years ago, my parents made love, and from half a billion sperm, I was the fastest. I was an accident, in both the unplanned pregnancy sense of the term and the truly cosmic nature of my improbable existence.
You want me to justify my existence? My amigo, after all that, I don't need to justify anything. I won the lottery of lotteries. My moral framework is OMG WTF I'M HERE. I'm just here to make the most of it and enjoy my 80+ (cross my fingers) trips around this boring run-of-the-mill hot pulsing orb of gas.
> I think it's not unreasonable that we are sort of early to the party. Earth has existed for about 1/3 of the lifetime of the universe
Universe begins
| 9.2 billion years
Earth formed
| 0.5 billion years
First life
| 0.5 billion years
First photosynthesis
| 3.0 billion years
Enough oxygen in air for macroscopic life
| 0.5 billion years
Now
The main work was:
(1) Supernovas creating heavy elements. At first, the universe is all hydrogen (and helium). It takes some generations of stars forming, and exploding as supernovas to create and spread around heavier elements, so that a planet like Earth can form, with all the minerals we have. Do we need 9 billion years for this, or could there have been planets with heavy elements, how much earlier? Is Earth among the first possible?
(2) It took 3 billion years of photosynthesis, by single-cell microbial life, to produce and accumulate enough oxygen. First the oxygen released into air would go and oxidize the minerals on Earth's surface. Only after the whole rocky surface was oxidized, would oxygen start to accumulate into the atmosphere. Somewhere around 10% or 13% atmospheric oxygen, it was enough that also other than flat, single-cell-layer multicellular macroscopic life could start to form, without the inner cells being starved of oxygen. 3 billion years of repetitive, grunt work by the microbes. (Then it took 0.5 billion years of evolution from the Cambrian evolutionary explosion, to humans.)
Compared to these two, the other steps took much less time.
But our galaxy and solar system is relatively young compared to the universe. Plus the universe is massive. There's approximately 10 billion galaxies in the observable universe with and average of 100 billion stars per galaxy. At that scale the processes that created life on Earth would have happened countless times before. The building blocks for life are common in the universe but weren't common on the early, inhospitable Earth. It was brought to our planet from comets which is where the Earth's water came from.
Eh? What about the lack of heavier elements at this stage of the universe? Or the fact that it wasn't this warm for the next 3-4 billion years (about the time it took to form complex life here)?
Also:
>By demonstrating that life could have formed so early, Loeb may even have delivered a blow to so-called anthropic arguments about life in the universe.
The Earth is only 4.5 billion years old and the Universe is 13.75 billion - doesn't that give rather a long time for a generation or two of stars to cook up the suitable elements for life and give it an opportunity to develop before the Solar System was formed?
[Reminds me of the ending of the novel "Heart of the Comet"]
>" A mix of random chance and physical laws happened to create the right environment for hydrogen and oxygen and carbon and nitrogen to exist in the same place at stable temperatures for a couple billion years, and we got life."
That sentence just skipped over the most important part of the whole question! :)
> For one thing, if you were an advancing species some 12 billion years ago (an era where there’s reason to think that biological life as we know it might have already been possible)
This was eyebrow-raising for me, as I thought the consensus was advanced civilization was only "recently" possible due to the lack of heavy elements in the first generations of stars. The article fleshes out this claim a bit at the end...
> During the period when biochemistry could have first got underway—some 100 million years after the Big Bang—the heaviest elements were woefully scarce as the first generations of stars forged new atomic nuclei.
> Bereft of those atoms, terrestrial-sized planets might have wound up as “carbon worlds,”4 chemically rich in some ways, but with a severe shortage of some of the heavier elements that today’s life fully relies on. Life could have gotten going, but with different restrictions and imperatives.
...but still seems to be making a giant unsupported leap from "life may have been possible without heavy elements" to "advanced civilization may have been possible without heavy elements"
Our Universe may support life for at least a trillion years. If so, our existence a mere 14 billion years after its creation is so improbable that we may well be the first
> Next take the entire volume of Earth's primordial oceans and multiply by a few hundred million years, roughly the period during which life arose on Earth.
Multiplied by more than two to the power of each quantum event of a certain type, if the Everret interpretation of quantum mechanics is true.
> i hear this argument constantly, but i've never been able to understand it. you say the universe is big and has existed for a long time, but compared to what?
I think compared to how long it took for somewhat intelligent life to evolve on Earth, from the point of first life. Assuming* a comparable evolutionary cadence, the question then becomes - how often does life begin?
*This I assume because the cadence of living things on Earth is at the very least tied to the day/night cycles, winter/summer seasons, and lunar tides, none of which are especially unique.
I understand where you're coming from. You're talking about stellar dispersion of elements-- which is true. Somehow this isn't relevant to forming life? I guess that's why none of the people shitting all over my musings in this thread are actually working in Physics and not just recounting what they read in a Pop Sci article. Dunning-Kruger effect, I guess.
> each planet as a specific combination of chemistry composition
But with any combination you try in the laboratory you get a very similar brown goo with a similar chemical composition. There are few atoms that are common and like to stick together to form molecules, so you get mostly some molecules with C, O, N, S, P, and H. Carbon atoms are happy to form long molecules. If you add a lot of Nitrogen atoms in a molecule, it is usually a good explosive and will react spontaneously (at low concentrations it only self destruct, it is difficult to get high concentrations and get an explosion). If you add a lot of Oxygen atoms two of them may decide to pick a Carbon atom and go away, something like
molecule --> CO2 + smaller molecule
So after a while you get brown goo a mix of molecules with more Carbons and a few of the other atoms. If you start with different mixes and different energy sources, you get a similar composition. There is some mix of molecules that are the result of random chemistry.
In this mix you get the building blocks of a lot of important current biological molecules, IIRC you get all the building blocks of RNA. RNA is a weird kind of molecule because they can induce reactions in other molecules and they can sorta self replicate like DNA. So one of the hypothesis is that the first life like thing has/was a bunch of RNA.
Life on Earth needed like 1 billon year to appear https://en.wikipedia.org/wiki/Life#Origin . So for an undirected a
experiment you need 1E9 years x 5E14 m^2, instead of a graduate student that has only 4 years x 1m^2 x 1m if s/he is running the experiment in a giant reactor instead of a beaker. That is a difference of more than 23 magnitudes orders.
For a directed experiment, nobody really knows. Perhaps the firs step is to get a lucky RNA of length 20 and you must try the 4^20 combinations until you get a crappy first version of a self reproductive RNA, that is not very good and only can make a good copy per year. Can you call it alive? Is this really the first step? Perhaps its length is 40, that needs exponential more combinations. The initial RNA had probably more than 4 bases, so the search space is even bigger and more difficult to estimate.
Perhaps the first step is to create small soap-like balls and put them near something like a thermal vent that release H2? Perhaps the first "life" form use some sulfur compound to get energy? Nobody is sure.
> There are things we still don't understand about it, but we understand some, and it's not magic.
> What's difficult to comprehend is the immense vastness of the universe.
We know a whole lot about ways life changes once it's there but we haven't observed life emerging from non-life and our hypotheses for how life emerged on earth has more holes than swiss cheese and it doesn't have to be magic in order to be exceedingly improbable. And magnitudes work in both ways, if it is sufficiently improbable for life to emerge, let's say 1 chance in 1E100 against then even if you had dice rolls in proportion to all the subatomic particles in the universe (~1E80) multiplied by the number of seconds since the big bang (~4E17) then it would still be about 3 orders of magnitude against the likelihood of life emerging even once. In this scenario if the probability was 4E97 then we'd expect for life to have emerged once. Until we have the data to infer what the probability actually is we can't determine which scenario is the case.
My understanding is the time when the universe was at life supporting temperatures, was long before the formation of the first stars and fusion of heavier atoms than hydrogen.
It is hard to imagine life without a large variety of atoms.
It is quite possible that we are one of the first ones. The universe as we know it is rather new. Our planet exists for a significant chunk of its total lifetime, and it needed heavier elements to be produced before it could coalesce.
The universe is expected to be teeming with purposeful matter eventually.
We'll learn much in the effort, but discover that humanity is not only the apex predator on Earth but also universally unique in attaining our level of self-awareness and escaping the cradle.
Restated: the quantum accidents that transitioned the periodic table of elements to self-replicating organic life are so gnarly and unique that we DO NOT find them recurring.
Subsequent theistic arguments are optional. Merely stating that all the Sci-Fi stays precisely that: fiction.
370,000 years after that, it cooled down enough to finally let protons bind to electrons, and the first atoms formed (99% hydrogen, 1% helium).
100M years after that, much of that hydrogen gas collapsed into stars, which underwent nuclear fusion to produce helium, carbon, nitrogen, oxygen, and other heavier elements up to iron. Some of those stars went supernova and released their enriched guts out into the universe.
After billions of years of that, we had enough heavier elements to form rocky planets, of which one is the planet we're on now.
Somehow on this wet rock, organic molecules formed and found ways to replicate themselves inside of membranes. A billion years after this wet rock came into existence, some of these replicating membranes bound to each other and started to act in harmony to ensure the continued replication of the whole group of membranes.
For another billion years, these groups of self-replicating membranes got larger and more complex. Eventually, one of them grew opposable thumbs, a large brain, and started to make tools. Those hairy apes, my ancestors, against all odds, for millions of years, fought against wolves, tigers, the elements, starvation, and each other to form an unbroken lineage that led to the existence of my parents.
36 years ago, my parents made love, and from half a billion sperm, I was the fastest. I was an accident, in both the unplanned pregnancy sense of the term and the truly cosmic nature of my improbable existence.
You want me to justify my existence? My amigo, after all that, I don't need to justify anything. I won the lottery of lotteries. My moral framework is OMG WTF I'M HERE. I'm just here to make the most of it and enjoy my 80+ (cross my fingers) trips around this boring run-of-the-mill hot pulsing orb of gas.
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