When Did Life First Emerge in the Universe?
scientificamerican.com
scientificamerican.com
> But life’s signatures will not last forever. The prospects for life in the distant future are gloomy. The dark and frigid conditions that will result from the accelerated expansion of the universe by dark energy will likely extinguish all forms of life 10 trillion years from now. Until then, we could cherish the temporary gifts that nature had blessed us with. Our actions will be a source of pride for our descendants if they sustain a civilization intelligent enough to endure for trillions of years.
Let’s hope we’re able to give the gift of wonder and awe to many more generations to come.
But rather soon after Earth has cooled down (i.e. about 1 billion years since the planet has formed), which is more relevant.
> seems to be a big fluke
So, no, it doesn't.
What really is necessary to know, I believe there is still debate, is whether main sequence supernovae can generate all the necessary elements. I believe gold and heavier are might not be possible with normal supernovae and may require neutron star mergers to generate.
I believe earth tectonics, not a small aspect of Earth's long term stability/cycle, need radioactives to maintain a liquid core (not to mention the magnetic shield provided by the core).
Still, an earth like world in a mostly stable/quiet area of a galaxy may be possible only a few billion years after the big bang with some luck with blue hypergiants and a lucky neutron star merger, if that is in fact necessary for heavy elements and radioactives.
> "We don't know ..."
Why does SA have to use such a clickbait-y title?
Because it's a good question, and the subject of the article.
> Our actions will be a source of pride for our descendants if they sustain a civilization intelligent enough to endure for trillions of years. Here’s hoping that we will act wisely enough to be remembered favorably in their “big history” books.
Obviously there is no way of knowing, but it was an amusing thought to consider for a moment.
There were millions of years when the universe was transparent and room temperature [1].
[1] https://www.cambridge.org/core/journals/international-journa...
But at that time, there must have been very few heavy elements so any life must have been "plasma life" and "room temperature" probably was very unpleasant for them.
Entire eons of civilizations could have arisen and disappeared, with their own "heat death" of the universe from their perspective. At some point, the universe would expand and cool to the point that the form of matter required for their existence would generally cease to exist, destroying everything from their civilization, utterly and completely.
In Roger Penrose's Conformal cyclic cosmology, another universe could arise after the heat death of our own, just at a different scale in time and space, where the cold, thin, red-shifted to oblivion photons left over from our universe would comprise a Big Bang in a far slower, cooler, and vaster universe.
Stephen Baxter's Xeelee series actually touches on quite a bit of that, but his writing is such that I'd honestly prefer to read it in outline form with the conceptual bits pasted in.
IIRC, the short story "The Quagma Datum" from Vacuum Diagrams deals with that most directly, and is similar the story your asking for, complete with an ark. Also the titular Xeelee are also survivors from the very early universe.
But I don't know what it is about his writing. It just isn't very gripping.
This opposed to f.e. Dragon's Egg by Robert L. Forward. Similar hard scifi, but much more fun to read.
He also reuses his "grand" ideas. For instance, I skimmed Xeelee Redemption because it's apparently the first book where he actually depicted a Xeelee, and a lot of the chapters were rehashes of ideas he'd previously explored (e.g. humans evolving into hive organisms, species surviving environmental destruction by becoming symbiotic composite organisms).
And suppose their replication had entailed production of entangled particles.
Without need for fast travel those particles would now exist everywhere in the universe. Having been carried here by expansion / inflation.
Many of those remnant particles / organisms would still be entangled, having never encountered another particle to cause their collapse.
This allows real-time (unconstrained by FTL) communication with arbitrary places in the universe.
We would communicate with this system using Earth-originated organisms at similar scale, collapsing those early entangled particles and watching the effect on our viruses' e.g. their spin.
[0] I grow ever more convinced that the Copenhagen interpretation is nonsense, but it's the easiest language to acknowledge the weirdness of spooky action at a distance.
EDIT: I misread what you wrote. It's not quite as related. But maybe only a little.
> Communication signals are not expected to be detectable across the universe, because the signal travel time would require billions of years in each direction and no participant would be patient enough to engage in such a slow exchange of information.
So effectively what we could search for is energy pollution from construction and transportation operations. Although it seems obvious in retrospect, it never occurred to me that intentional communication signals would not have the appropriate characteristics to be detectable across vast distances of space and time.
OTOH, also worse because it’s unlikely to be directional, so the output would have to be powerful even compared to the galaxy it’s part of for an intergalactic detection.
Then travel time to another star doesnt require antimatter, it just needs a long nap
Literally can do the same thing with unentangled pairs with all the benefits (except one) with none of the downsides! The reason to do so (which is an awesome reason) is secure communication.
A frequency so slow that the billions of years elapsed since the creation of the universe, used negligible computation power compared to the resources needed for a single second one century later when the simulation had to be halted having exhausted all computational credits.
It begs the question : how much information is there in a drop of water ?
Does the algorithm has to simulate every one of the water molecules, or can it adaptively only needs to preserve the macroscopic quantities while preserving the consistency of the microscopic level (aka information conservation).
Most physical phenomenons exhibit some degree of self synchronization, and self similarity, witness of some kind of information redundancy. It happens at all scales of the universe, from particles which self-organize into crystals, spinning rocks coalescing into planets, stars forming black-holes to store information on their surface instead of the volume.
All these physics rules allow huge speed-up in computation, because once a quantity doesn't change, a billion years for a billion stars can go in an instant.
Information is conserved, but information wants to diffuse. That is the cosmic entropic battle which life is fighting.
Life are the computations which can't be shortcutted.
I was watching a documentary and I heard about the problem of information does not disappear in the universe. What does this mean. I have a feeling that information in quantum physics has a different meaning but I don’t understand what it is.
(You can look at the technical concepts of "Fisher Information" and "conservation of probability", if you want more details for the quantum case)
It's then about, what you want to describe.
In quantum physics you want to describe the full state. In our world you want to describe statistics about the full state we have access to : the "observables".
Among those statistics there are some quantities which are expected to be conserved and easily accessible. In our day to day language information is about the value of these quantities, and the number of bits necessary to describe these values, which is a lower bound of the full state uncompressed information.
When we have the full state, the rules of evolution are reversible therefore you cannot lose information, if you know the full state at any one time, you can know it at any other time in the future or past, it's just a matter of computation to time-evolve the system.
What gets fun is that information can get compressed. Imagine dropping a piece of glass to the floor and it shatters.
Before the shattering it can easily be described as a uniform square of glass, but after, you have to describe the positions of every pieces. But because the system is deterministic there is the same information before and after : you can describe it simply by stating it's the time-evolution of uniform square of glass at time post-shattering.
But if you want to do some computation on it, you can't always work in compressed form. You then need to find a suitable representation which allows to perform the computation you need efficiently.
How much will need to be materialized will depend of the rules of your system.
That's one hell of a refutation.
> In particular, photosynthesis or chemosynthesis is needed to be independent from organic resources.
It's weird because the current estimation is that photosynthesis appeared like 1000 millions years after the fist cell. So if this article were correct and the initial cells population came from space, they probably would no have photosynthesis.
(With 1 molecule per cm^3, you get like 10 more bases in locations for random chains.)
It's actually more complicated, because shallow part of the sea or fumes near ocean rigs may have more concentration, and 1 molecule per cubic meter is a very low concentration. Anyway, extrapolating to 1 base is too extreme.
Also, they had a nice fit for DNA based life, and they discuss the RNA World hypothesis, but it's not clear that the fit for DNA can be extrapolated to the RNA or whatever was used before.
(There is a recent paper that propose a mix of RNA and DNA instead of a pure RNA word. We still don't know.)
On other hand good question is how much faster evolution of more "complex" life could have been.
My favorite thought experiment is imagining a future earth civilization that does check everywhere in the universe and then it finds no signs of life now or in the past.
After all, it took ~billions of years for life to evolve on Earth and we're not immensely different than a monkey or dog.
Also, we have very few genes compared to all other animals, we're like a 7zip of genetic information, each gene coding multiple proteins, a spaghetti dna code that's very good at what it does, but surely it limits evolution.
If there is anything at all to evolve at, intelligence/emotional wise.
What would a human or alien species with an iq of 1000 be able to achieve vs what we can achieve in the exact same Universe?
On the other hand, it is very easy to imagine an alien species that would have the same intelligence as humans, except that its thinking speed would be several orders of magnitude higher, because it would not be limited by the slow velocities of ions in liquids, like in the animal nervous systems.
The interactions between us and such aliens could be like the interactions between a sea star and us, even if they would not have a higher IQ.
~80% of time waiting for Oxygen Catastrophe, which was random (but was result of evolution, nonetheless). It wasn’t like start, billions of years, end. Organisms that we call non-bacteria non-algae are less than a billion years old, roughly.
For life to appear, about 1.
May 13th 1936; the date when "they" rolled out the "life" patch ocf
Some people, like what you say, do not have faith in free will.
I find it funny when nonbelievers profess to know the truth with such certainty.
Why did their carbon atoms have to type this on HN?