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Another idea is those friendly conditions only seem to have occurred once here on Earth - everything living is descended from that one Thing.

That's the kind of train of thought that keeps me up at night.




At astronomical timescales even Earth's life is just a blink of an eye. It's not at all unlikely that life on other planets happened, is happening or will happen somewhere out there. The odds are just pretty good that we'll never be able to find out because we not only happen to be in the wrong place to observe it, but also in the wrong time.

That's pretty depressing IMO.


> At astronomical timescales even Earth's life is just a blink of an eye.

Age of the universe: ~13.8 billion years

Life on earth: ~4.1 billion years

That's a decent chunk, not the blink of an eye.


Yeah, it would be really fascinating if it turned out that life rare is in space, but not so rare in time.


> Age of the universe: ~13.8 billion years

If the age of the Universe is 13.8 billion years, I wonder, what was happening 13.9 billion years ago? What about 13.8^2 = 190 billion years ago and even before that ?

Kind of mind bending, but time seems to be infinite (at least to us) so at that scale, the life of Earth is really a blink of an eye or less.


As far as we know, time began 13.8 billion years ago. Talking about events before that is not meaningful.


Well, time is "synonymous" with change. So talking about events before "change" began is indeed not meaningful. But it is still meaningful to ask if there was change before the point where most people think there was no change.


Oh, it's more complicated. Talking about time gets weird when masses and energies are in the relativistic realm.


> As far as we know

What we 'know' is given to us by the mathematical models which we invented to describe the observed reality.

Currently, we have different models to describe reality based on the scale of observation.... Which is interesting because as you zoom into the microcosmos there's a point were the laws of physics magically 'switch' from relativity to quantum mechanics.

As a programmer who is not a physicist, I can smell a hack right there. Which brings me to the inevitable conclusion that maybe our model of reality is not entirely correct.

So if I were to bet on weather time existed before our model's mathematical moment zero or that our mathematical model is imprecise, I would definitely choose the infinity of time.

Our mathematical model is for us or future generations to adjust to whatever we discover in the future.


> Currently, we have different models to describe reality based on the scale of observation.... Which is interesting because as you zoom into the microcosmos there's a point were the laws of physics magically 'switch' from relativity to quantum mechanics.

There is no hack and there is no switch. QM and relativity are just abstractions at different scales over the same underlying principles. We do have a problem of stiching them together, but that's just us not having figured out the relevant math yet. But you're not free to notice a problem in one part of the model and then discard the parts that match the reality pretty well. Any updated, better, unified model invented will not differ in its predictions from QM at scales and precision levels where QM is applicable, because our present models are based on empirical observation. Transition from Newtonian to relativistic models didn't make apples fall up.

"Time" is also something we define and is valid only within that definition. For now, "time" starts with the universe, so the question of what was before is meaningless and will be, until we find a plausible way to extend the concept beyond the beginning of the universe.

The map and territory analogy is a really good thing. The territory doesn't change in any way when you make a better map.


Try as they might, physicists haven't found any way to adjust it that allows for an infinite time while also being consistent with so many observed phenomena. Of course we could make up an ad hoc model that says "It just is" but the big bang model is more consistent with observation than anything else we have.

We don't have freedom to just change it. We first have to find a possible valid way to change it and nobody has. Also nobody's found a way to fuel a car with water, fly on magic carpets or travel back in time to meet our grandparents. It might turn out to be impossible. Would you bet on those things happening one day? As another commenter said, your intuition is no match for nature - it's based on human's very narrow experience of the world, our inability to see how limited the concepts we can imagine are and our arbitrary biases for the ideas we like at the expense of ones we don't understand.


> As a programmer who is not a physicist

Let me stop you right there...


>What we 'know' is given to us by the mathematical models which we invented to describe the observed reality

So, do you have to propose anything better?

Mere intuition "but time seems infinite" is not that.


> So, do you have to propose anything better?

If I did, would anyone listen to it here ?

The point being that, throughout history humans always had a dominant theory about the origin of Universe and it was considered the truth at the time.

The bing bang theory is one such theory which is currently accepted as 'truth' by the scientific majority, but it is not the last and not the only theory explaining the origins of the Universe.

The man himself said it:

"We may now be near the end of the search for the ultimate laws of nature." - Stephen Hawking


> If I did, would anyone listen to it here ?

Maybe not here, but people would read a good paper on Arxiv.


Asking "what happened before the big bang?" isn't necessarily any more meaningful than asking "what's beyond the edge of the screen in a Pac-Man game?" or "what's the predecessor of a Garden of Eden configuration?"


Earth didn't exist 13 billion years ago. By most calculations Earth is only 4.5 billion years old.


Sorry, did you mix something up? I'm not even mentioning the age of the earth anywhere.


Not necessarily. For all we know, abiogenesis may have occurred many times on the early Earth, it's just that the lineage that lead to extant organisms is the only one that survived.


Nick Lane makes the argument that abiogenesis of our kind of life itself has very specific conditions involving warm alkaline thermal vents (not the hot super smokers, but the kind) and iron rich water oceans.

But he also points out that the development of eukaryotes, which are a class apart from prokaryotes (1000x the size and probably 1000x as complex) is even more of a mystery/fluke. And, again, looks to have happened just once in 4 billion.

Some series of unlikely events.




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