If humanity became extinct at some point in the future

[StringJunky]

Perhaps we are the only life that ever did or ever will form in the universe.

 

There could have been a recycling universe and after billions of iterations we are still the only place life has ever started.

 

Speculations are great fun, but when we look at actual data points, we still have evidence for only one start of life. Given the data thus far it is not unreasonable to suggest that abiogenesis may be a rare event.

Those were not idle speculations thought up by myself and your position on this is more unlikely. Chemical reactions are deterministic processes and will happen and have happened. The observable universe is 96 billion LYRS in diameter and we' are only just studying Mars - 3 light minutes away - in sufficient depth; a rather small and unrepresetative sample, don't you think?

[zapatos]

Found this interview with an evolutionary biochemist quite interesting.

I thank you for that. The interview you found regarding the chemistry of the ocean supports my position that started my conversation on this topic; "I suspect we either currently have the wrong environment for it, or it is simply extremely rare."

 

Frankly, I'm quite surprised this position has received so much pushback. If anyone would care to point out evidence that we do have the right environment for new life to form, or that abiogenesis is not extremely rare, I'd love to see it.

Those were not idle speculations thought up by myself and your position on this is more unlikely.

I'll concede my speculation is indeed more unlikely as I was simply countering one speculation with another.

 

But I've never claimed abiogenesis won't happen again. I only suggested that given the evidence thus far, it might be rare.

 

The fact that my speculation is less likely than yours, does not in any way suggest that abiogenesis is not rare.

 

 

Chemical reactions are deterministic processes and will happen and have happened. The observable universe is 96 billion LYRS in diameter and we' are only just studying Mars - 3 light minutes away - in sufficient depth; a rather small and unrepresetative sample, don't you think?

I think it is a mistake on your part to leave out our observations past Mars. There is a reason SETI uses their particular strategy in the search for life.

[dimreepr]

I thank you for that. The interview you found regarding the chemistry of the ocean supports my position that started my conversation on this topic; "I suspect we either currently have the wrong environment for it, or it is simply extremely rare."

 

Frankly, I'm quite surprised this position has received so much pushback. If anyone would care to point orut evidence that we do have the right environment for new life to form, or that abiogenesis is not extremely rare, I'd love to see it.

 

The problem with that argument is time; maybe abiogenesis is impossible now, but as previously pointed out oxygen would soon fall to zero without life, so at some point in the future, given the right conditions and our only data point, suggests it would almost certainly occur again.

Edited May 6, 2017 by dimreepr

[zapatos]

The problem with that argument is time; maybe abiogenesis is impossible now, but as previously pointed out oxygen would soon fall to zero without life, so at some point in the future, given the right conditions and our only data point would, almost dictate, life will occur again.

I don't mean to be rude, but will you please provide some scientific references to back up that assertion?

 

I am unaware of any science that supports your claim that life on earth is almost a certainty.

[StringJunky]

I don't mean to be rude, but will you please provide some scientific references to back up that assertion?

If the same local conditions exist, like oceanic vents, for instance, and bearing in mind chemistry is deterministic, it should happen again.

[dimreepr]

I don't mean to be rude, but will you please provide some scientific references to back up that assertion?

 

Which one?

We are one among billions upon billions of other planets/moons; probability dictates given enough iterations, it will happen again, that's axiomatic.

Edited May 6, 2017 by dimreepr

[zapatos]

If the same local conditions exist, like oceanic vents, for instance, and bearing in mind chemistry is deterministic, it should happen again.

Just as I asked of dimreeper, will you please provide some scientific references to back up that assertion?

 

 

Which one?

 

The one I highlighted for you.

 

"oxygen would soon fall to zero without life, so at some point in the future, given the right conditions and our only data point would, almost dictate, life will occur again."

 

We are one among billions upon billions of other planets/moons; probability dictates given enough iterations, it will happen again, that's axiomatic.

 

Then it's a good thing I'm not asserting it will never happen again anywhere in the universe. Do I really need to remind you that my only claim was that it may be a rare event?

[dimreepr]

Just as I asked of dimreeper, will you please provide some scientific references to back up that assertion?

 

 

The one I highlighted for you.

 

"oxygen would soon fall to zero without life, so at some point in the future, given the right conditions and our only data point would, almost dictate, life will occur again."

 

The one you highlighted contains two assertions:

 

"Oxygen would soon fall to zero without life" - I can't remember where I read this but IIRC oxygen is very reactive and oxidates everything it can, so without life to replenish free oxygen it would diminish, at least (I'll keep digging).

 

"at some point in future life will occur again" - It has happened once, so with infinite iterations, it will happen again.

[zapatos]

 

The one you highlighted contains two assertions:

 

"Oxygen would soon fall to zero without life" - I can't remember where I read this but IIRC oxygen is very reactive and oxidates everything it can, so without life to replenish free oxygen it would diminish, at least (I'll keep digging).

 

"at some point in future life will occur again" - It has happened once, so with infinite iterations, it will happen again.

 

I'm not used to you being the type to move the goalposts so much.

 

I'll drop out at this point.

[dimreepr]

 

I'm not used to you being the type to move the goalposts so much.

 

I'll drop out at this point.

 

My position hasn't changed, please be specific?

 

BTW there's nothing wrong in admitting you've learnt something, I've learnt from you many times.

[zapatos]

My position hasn't changed, please be specific?

 

The remaining duration of the earth does not allow for infinite iterations.

 

This started out as a conversation about the likelihood of abiogenesis occurring again on Earth if all life ends, and it keeps moving to whether or not abiogenesis can occur anywhere in the universe given an unlimited amount of time. I have never suggested that life is unlikely to occur somewhere in the universe, or even on Earth, given enough time, so there is really no point in people telling me it is possible.

 

If anyone can provide pragmatic support for the assertion that abiogenesis is again likely to occur on Earth if all life ends here, I'd love to see it. Otherwise we just seem to be going in circles.

[dimreepr]

Otherwise we just seem to be going in circles.

 

I agree, lets leave it there.

[Bender]

I won't leave it, since I didn't shift any posts

 

The remaining duration of the earth does not allow for infinite iterations.

We have only one data point, which states that life started within at most a couple of 100 million years after the conditions were there.

 

If it was rare enough that it would only happen, on average, after 5 billion years, then our single sample is pretty unlikely. It does not provide strong support of that hypothesis.

 

So, yes, it might be rare, and we might be on a planet where it happened extraordinarily quickly. It might also not be rare, a hypothesis which aligns better with our one data point.

Edited May 7, 2017 by Bender

[zapatos]

If it was rare enough that it would only happen, on average, after 5 billion years, then our single sample is pretty unlikely. It does not provide strong support of that hypothesis.

That makes no sense to me at all. You are saying that if it is rare enough to happen only once every 5 billion years, then it us unlikely that it would have happened here once after 5 billion years.

 

So, yes, it might be rare, and we might be on a planet where it happened extraordinarily quickly.

If something takes 200,000,000 years to occur when the conditions are correct, I think we should be careful about labeling that "extraordinarily quickly'.

 

It might also not be rare, a hypothesis which aligns better with our one data point.

 

 

I'll admit I'm no statistical expert, but can you please go into a bit more detail on how our one known occurrence in five billion years aligns better with the idea that abiogenesis is not rare? That seems like rather convoluted logic.

[Bender]

As far as we know, it happened only once in a couple of hundred million years. After that, the conditions were gone.

It might have happened more often, but one could have outcompeted the others or different rudimentary life forms might have merged somehow. It would be impossible to find any evidence of the former, and difficult to find any for the latter. For the arguments sake, let's just assume it happened once.

 

If it happens on average once every 5 billion years, then the probability of it happening in the first 250 million years is about 5% (it is actually less, but close enough).

 

If it happens on average once every 250 million years, the probability of it actually happening in those 250 million years is about 63%.

 

So which hypothesis is more likely? The one where our observations are pretty unlikely (5%), or the one where our observations are very likely (63%).

 

Compare it to going somewhere, and the day you arrive, it rains. If that is the only observation you have, will you conclude that rain is rare in that location?

 

Note that if the average occurrence is only once every 5 billion years, it is still pretty likely to happen within the lifespan of the Earth. If you want that to be unlikely, you have to decrease the likelihood to e.g. once every 50 billion years, which in turn decreases the likelihood of our observation to about 0.5%.

Edited May 8, 2017 by Bender

[zapatos]

Very good argument. +1

 

Unfortunately our one lousy data point leaves a lot to be desired, but your analysis lets me look at this with a better perspective.

[Bender]

Indeed you don't want to draw too much conclusions from one data point.

 

It is refreshing to see that some people can actually read an argument and allow their perspective to be changed . If you see some threads here, that must be a very difficult thing to do.

[Raider5678]

Note that if the average occurrence is only once every 5 billion years, it is still pretty likely to happen within the lifespan of the Earth. If you want that to be unlikely, you have to decrease the likelihood to e.g. once every 50 billion years, which in turn decreases the likelihood of our observation to about 0.5%.

Actually, anything above 5 billion years, and the sun would be a red giant and most likely consume Earth.

 

Wait. Stop. I KNOW THERE ARE OTHER POSSIBILITIES! But the most likely one, is that earth is consumed. I'm not turning this into a debate about what will happen to earth.

 

In the event that earth is consumed, no life will form.

So you have a 5 billion year window if life were to die off right now.

All life. Including bacteria.

If it happens every 50 billion years, then the likely hood of life happening ever again on earth is really slim.

I'll admit I'm no statistical expert, but can you please go into a bit more detail on how our one known occurrence in five billion years aligns better with the idea that abiogenesis is not rare? That seems like rather convoluted logic.

I still stand on the idea that abiogenesis never happened. Just letting you know. But ignoring that for now.

 

 

 

I would frankly agree with you, that life happening in 5 billion years is something I would consider rare. Given the idea that a random organism managing to show up would probably die off unless it just happened to have the right conditions. Even if those conditions were that it only needed one carbon atom a day to survive.

Abiogenesis suggests the chemicals and other things created the life form. Doesn't mean that that life form will form directly ready to live in the environment it's created in. The chemicals, I'd assume, would be pretty random on what they create so I doubt they'll specifically create a single celled organism with DNA adapted to it's environment. Unless I'm completely wrong and it does create it based on it's environment. I don't really know. And frankly nobody does.

Which lowers the rate of life showing up to extremely small chances.

Unless, it's happened often(1 million years maybe?) except the organism was rarely adapted to it's environment.

Abiogenesis, is a theory that's extremely hard to test. All we know, is that life showed up. Studying Abiogenesis and the likely hood of it happening, is hard to do.

[zapatos]

I still stand on the idea that abiogenesis never happened. Just letting you know. But ignoring that for now.

What is it that you think did happen?

[Bender]

Actually, anything above 5 billion years, and the sun would be a red giant and most likely consume Earth.

Which is why I said that in that case it is only "pretty likely" to happen, a probability somewhere in the neighborhood of 50%.

 

I would frankly agree with you, that life happening in 5 billion years is something I would consider rare. Given the idea that a random organism managing to show up would probably die off unless it just happened to have the right conditions. Even if those conditions were that it only needed one carbon atom a day to survive.

Abiogenesis suggests the chemicals and other things created the life form. Doesn't mean that that life form will form directly ready to live in the environment it's created in. The chemicals, I'd assume, would be pretty random on what they create so I doubt they'll specifically create a single celled organism with DNA adapted to it's environment. Unless I'm completely wrong and it does create it based on it's environment. I don't really know. And frankly nobody does.

Which lowers the rate of life showing up to extremely small chances.

Unless, it's happened often(1 million years maybe?) except the organism was rarely adapted to it's environment.

Abiogenesis, is a theory that's extremely hard to test. All we know, is that life showed up. Studying Abiogenesis and the likely hood of it happening, is hard to do.

There were a lot of molecules thermally vibrating around at the time of abiogenesis. Even a teaspoon of water contains about 10^23 water molecules. If the water contains only a tiny fraction of molecules of the kind that are required of life, that is still a very, very large amount of molecules. You are right that they probably died off. They might have died off millions of times, yet at one point, it didn't die off, because dying off is only very probable and there are a lot of molecules.

 

A nice example of spontaneous assembly can be found in this video, where some rudimentary blocks organise themselves in a sphere simply by shaking them, which represents thermal agitation.

 

Also, the fact that you (or anybody else) don't know has no influence whatsoever on the chance of the life showing up.

[StringJunky]

Abiogenesis, is a theory that's extremely hard to test. All we know, is that life showed up. Studying Abiogenesis and the likely hood of it happening, is hard to do.

However the story of early life is ultimately written, Abiogenesis is the title of that story.

Edited May 8, 2017 by StringJunky

[Bender]

I just saw an episode of "Human Universe" which raised some interesting points relevant to this discussion.

 

- Abiogenesis may have happened very quickly and may happen on billions of planets in our galaxy, but the transition from bacteria to complex life (Eukaryotes; symbiosis between cells and mitochondria) happened only once and it took several billion years to happen.

So while the universe might be thriving with bacterial life (or similar), complex, multicellular could be extremely rare.

 

- Von Neumann machines: in a couple of centuries, humanity could probably build autonomous interstellar probes that can travel to other stars, mine asteroids there and replicate themselves. Suppose they travel at 0.1% of the speed of light, and most stars are withing 50 000 light years from Earth, it would take 50 million years of travel.

There are about 100 billion stars, let's put them in a flat square lattice, 100 stars high and 30 000 stars across, so the Von Neumann machines would (at worst) need to replicate 15 000 times to span the entire galaxy. If a single replication takes 100 years, that is another 1.5 million years, so negligible on the total time.

Given that, if each Von Neumann machine replicates itself a number of time, this expansion will go exponential, a similar civilisation as ours could visit the entire galaxy in only 50 million years. Colonisation in generation ships probably takes longer, but perhaps only 500 million years.

None of this requires super fancy technology such as FTL travel.

The fact that there are billions of earth-like planets where life could have evolved, and many of them are older than our solar system, they should already have been here if intelligent life was likely. (or all of such civilisations have a prime directive)

[Thorham]

a similar civilisation as ours could visit the entire galaxy in only 50 million years.

Only 50 million years? Lol

[Moontanman]

I doubt it. Dolphins are smart but not that smart. I doubt a dolphin can understand quantum mechanics and general relativity.

 

Personally I think it would take at least 3 billion years before another species would be able to rediscover and reproduce everything which is about the same amount of time that it has take humans.

 

 

Why? How can you say what a dolphin can or cannot understand? Maybe sperm whales with their huge brains already know everything and spend their time hashing out the details..

Only 50 million years? Lol

 

 

Actually it's more like 250 million years, just a blink in cosmic time really...

[Delta1212]

Actually, anything above 5 billion years, and the sun would be a red giant and most likely consume Earth.

 

Wait. Stop. I KNOW THERE ARE OTHER POSSIBILITIES! But the most likely one, is that earth is consumed. I'm not turning this into a debate about what will happen to earth.

 

In the event that earth is consumed, no life will form.

So you have a 5 billion year window if life were to die off right now.

All life. Including bacteria.

If it happens every 50 billion years, then the likely hood of life happening ever again on earth is really slim.

I still stand on the idea that abiogenesis never happened. Just letting you know. But ignoring that for now.

 

 

 

I would frankly agree with you, that life happening in 5 billion years is something I would consider rare. Given the idea that a random organism managing to show up would probably die off unless it just happened to have the right conditions. Even if those conditions were that it only needed one carbon atom a day to survive.

Abiogenesis suggests the chemicals and other things created the life form. Doesn't mean that that life form will form directly ready to live in the environment it's created in. The chemicals, I'd assume, would be pretty random on what they create so I doubt they'll specifically create a single celled organism with DNA adapted to it's environment. Unless I'm completely wrong and it does create it based on it's environment. I don't really know. And frankly nobody does.

Which lowers the rate of life showing up to extremely small chances.

Unless, it's happened often(1 million years maybe?) except the organism was rarely adapted to it's environment.

Abiogenesis, is a theory that's extremely hard to test. All we know, is that life showed up. Studying Abiogenesis and the likely hood of it happening, is hard to do.

 

 

You're jumping way too far ahead. You don't get a single-celled organism spontaneously assembling in the primordial soup. All you need is a molecule that makes more of itself, which does not need to be nearly as complicated as cellular life.

 

Once it starts replicating, you get imperfect replications. That leads to differences in the copies. Some of the differences will mean that the copies can't replicate. Some will mean they replicate more poorly. And some will mean they replicate better. The better replicators will grow to outnumber the others because they are better at replicating and the same process will take effect with each round of copying.

 

 

The primary focus of life is not survival. It is that replication. The early precursors wouldn't need to maintain homeostasis (i.e. "live"). They'd just need to be in an environment that allowed them to replicate themselves. And they wouldn't crop up in the first place except in such an environment pretty much by definition. (A self replicating molecule isn't a self replicating molecule if it can't replicate itself). The rest of the stuff life does gets picked up along the way from lucky accidents in the way of replication errors that get selected for because they allow the replicating molecules to: replicate more accurately, maintain their own environmental bubbles that are suitable for replicating (i.e. cells), gather more raw materials and energy for fueling the replicating process and so on.