Do aliens exist?

[donglepuss]

I personally don’t think they do. I’d love to hear your guys’ opinions.

 

[russ_watters]

Probably.

 

[donglepuss]

Probably.

Why?

 

[russ_watters]

Why?

It's too easy and there are too many opportunities, for it not to.

 

[donglepuss]

It's too easy and there are too many opportunities, for it not to.

Life started exactly once in 4.5 billion years on earth. The strongly implies that it’s a one off event.

 

[russ_watters]

Life started exactly once in 4.5 billion years on earth. The strongly implies that it’s a one off event.

It started basically as soon as it became possible (the Earth became habitable). That strongly implies it was easy/inevitable. The fact that it happened only once doesn't mean anything since once it starts, that form of life dominates. Indeed if it started 50 other times but all of them were short-lived, we would never know.

 

[Chunkythunk]

I personally don’t think they do. I’d love to hear your guys’ opinions.

Yes, the universe is most definitely vast enough for more life harbouring plants to exist.

 

[anorlunda]

Life started exactly once in 4.5 billion years on earth. The strongly implies that it’s a one off event.

We don't know that. It might have started more than once independently here on Earth.

There could be a new life form forming on Earth today. It might be dead by tomorrow. We'll never know about it.

 

[phinds]

Life started exactly once in 4.5 billion years on earth.

Do you have evidence of that? How do you know that it didn't start in more than one place and/or at more than one time? You have great confidence in something that you have no evidence of. That sounds more like religion than science.

 

[PeroK]

I personally don’t think they do. I’d love to hear your guys’ opinions.

The honest answer is that no one knows. The statistical argument that it's inevitable as there are so many other stars is actually not valid. It may be that the evolution of life has an extremely low probability that outweighs the large number of opportunities.

If you look for videos by David Kipping, he explains the weaknesses in the purely statistical argument.

I should say I used to believe the statistical argument. But, I think Kipping is correct and it's not a watertight argument.

 

[donglepuss]

The fact that it happened only once doesn't mean anything since once it starts, that form of life dominates.

Do you have any evidence for that claim?

 

[nuuskur]

Life started exactly once in 4.5 billion years on earth. The strongly implies that it’s a one off event.

Please elaborate.

I believe at least more primitive life exists elsewhere, but I have nada to back that up.

 

[Vanadium 50]

If there were ever an "overly speculative" thread, this would be it. Come and draw conclusions from insufficient data! Come and draw conclusions from insufficient data!

Isn't this supposed to be a science forum?

 

[Astronuc]

Life started exactly once in 4.5 billion years on earth.

"It started 'at least' once" would be a more accurate statement; we know it started at least once, since we exist to ponder our existence and whether or not it could happen elsewhere in he universe. How it started and how it continued/evolved, or started, then stopped, then restarted, . . . . one can only speculate.

One might however conclude that the probability is very low consider the seemingly unique conditions under which our solar system developed and evolved, and the seemingly unique conditions under which we exist now.

If there were ever an "overly speculative" thread, this would be it. Come and draw conclusions from insufficient data! Come and draw conclusions from insufficient data!

Well, we could turn it around and apply an objective and critical analytical method to the question to look at evidence from earth and other planets, consider the pros and cons, and may be make a statistical estimate, or at least consider the variables.

 

[Vanadium 50]

Do you have any evidence for that claim?

Seriously? You're asking for evidence?

This whole thread - which you started - is people drawing conclusions from skimpy or missing data. Why are you surprised that you are getting replies like this?

One could draw exactly the opposite conclusion from yours - it happened quickly, therefore it's common.

But in any event, asking people for ill-supported opinions is going to produce ill-supported opinions. Pretty much no way around that.

 

[russ_watters]

Do you have any evidence for that claim?

This is behind a paywall, but the thesis follows what I'm saying:
https://www.newscientist.com/articl...sily-that-it-started-not-once-but-many-times/

There's multiple ways for it to happen that many became one, with strong (something drove it) and weak (it was coincidence) methods.

 

[russ_watters]

If there were ever an "overly speculative" thread, this would be it. Come and draw conclusions from insufficient data! Come and draw conclusions from insufficient data!

Isn't this supposed to be a science forum?

What we can do with this is ensure the question is properly framed and explored. There aren't overly speculative topics, only overly speculative approaches to investigating them.

 

[Vanadium 50]

Sure, we can write down the Drake equation. But that just moves the problem one back. "I think this term is 0.9". "I think it is 0.1". "I think it's 0.0000000001".

And we're quickly back in "everybody is entitled to his own opinion" land.

FWIW, I like broccoli.

 

[russ_watters]

Sure, we can write down the Drake equation. But that just moves the problem one back. "I think this term is 0.9". "I think it is 0.1". "I think it's 0.0000000001".

And we're quickly back in "everybody is entitled to his own opinion" land.

The Drake equation's value is in identifying what the parameters are/what needs to be investigated to answer the question. It's undeniable that we've made progress on that front in the 60 years since it was invented.

 

[Vanadium 50]

And yet whether N =1, N>1, or N >>1 is still a matter of opinion.

The facts are mighty slim:

1. Life appeared on earth at least once, and it happened pretty much right away.
2. Mars is not Barsoom.

 

[DaveC426913]

Life is not a magical, ineffable thing. It is "just" chemistry (albeit very complex chemistry), but it didn't start out complex.

There are only so many elements to mix into a soup (simple life only needs, what, four or so of the most common elements?). It is mostly a question of how many times environments crop up that are conducive to mixing them.

I'd think lipids can form pretty spontaneously in such primordial soup. Lipids can form enclosed membranes, which is (or may be) the first step on the path to a controlled inner environment.

So the other side of the OP question is: given the apparently huge number and variety of exo-planets, surely there are plenty that have liquid water and primordial soup - so how would chemical processes not follow a similar path to what happened here?

 

[anorlunda]

So the other side of the OP question is: given the apparently huge number and variety of exo-planets, surely there are plenty that have liquid water and primordial soup - so how would chemical processes not follow a similar path to what happened here?

Life starting and life surviving to evolve are very different propositions.

 

[DaveC426913]

Tru dat.

 

[PeroK]

Life is not a magical, ineffable thing. It is "just" chemistry (albeit very complex chemistry), but it didn't start out complex.

There are only so many elements to mix into a soup (simple life only needs, what, four or so of the most common elements?). It is mostly a question of how many times environments crop up that are conducive to mixing them.

I'd think lipids can form pretty spontaneously in such primordial soup. Lipids can form enclosed membranes, which is (or may be) the first step on the path to a controlled inner environment.

So the other side of the OP question is: given the apparently huge number and variety of exo-planets, surely there are plenty that have liquid water and primordial soup - so how would chemical processes not follow a similar path to what happened here?

How many advanced civilizations do you think there are currently in the Milky Way?

a) 1 - Only us.
b) 2-9
c) 10-99
d) 100-999
e) > 999

Justify your answer.

 

[Algr]

a) 1 - Only us, due to fermi paradox.

What "Happened quickly" is reproducing molecules and single celled organisms. That suggests that only life on that level is common on other planets. The development of anything with a brain took the vast majority of Earth's history. From there, human-level intelligence is an equally small fraction of the time left. So it is reasonable to assume that even animal-level intelligence is very rare, and human level might indeed be unique.
The consequences of the alternative are rather dangerous for human survival. Only about 800 years separated the technology of the Native Americans to that of the Europeans. An intelligence with a 10,000 year advantage might see us as we see single celled organisms.

 

[DaveC426913]

How many advanced civilizations do you think there are currently in the Milky Way?

a) 1 - Only us.
b) 2-9
c) 10-99
d) 100-999
e) > 999

Justify your answer.

I can't justify any answer I might give.

My personal hypothesis though is that the complexity of Earthly evolution over 3.5 billion years of time might be a rough statistical yardstick to how complex life we might find over space.

In other words (assuming a "dumb" manual search) for every planet we find with an advanced civilization, we will first have to encounter:
- a hundred that are of mammalian complexity,
- a thousand of insect complexity,
- ten thousand of algal complexity
- a million of multi cellular complexity, and
- a billion of single-celled complexity.

They never talk much about these worlds in any science fiction stories I've read. They'd ought to be be hip deep in them! Why doesn't every "Federation of the Five Planets" span a million worlds covered in nothing but blue-green algae?

 

[Algr]

My personal hypothesis though is that the complexity of Earthly evolution over 3.5 billion years of time might be a rough statistical yardstick to how complex life we might find over space.

Yes, that is more or less what I was trying to say. I think you are a bit more concise.

Why doesn't every "Federation of the Five Planets" span a million worlds covered in nothing but blue-green algae?

Isaac Asimov's Foundation series is like this. Firefly also didn't have aliens. In Blake's 7, the only aliens come from another galaxy, and are only in maybe one or two episodes. No aliens on other planets, just some fungi and things. In something like Star Trek, there are probably a limited number of stories you can tell about such planets.

 

[DaveC426913]

Digression into fiction:

Isaac Asimov's Foundation series is like this.

I just read that (finally) a few years ago, but I don't recall that.

Firefly also didn't have aliens.

They were really vague about just how large the 'verse was.

In something like Star Trek, there are probably a limited number of stories you can tell about such planets.

Yes, it would be more suited to world-building in a novel that has time to expound upon subtleties, where it can be talked about and exposited on, with taking up valuable screen time. Although, heck, it wouldn't have to be much more than a mention of "my time among algae-farming worlds out near the rim".

Even further digression:

Larry Niven wrote a short story "Bordered in Black" that, to this day, still haunts me. It was about a "food world" for an alien species consisting entirely of humanoids. Trillions of them - naked, tool-less without even houses; all flora and fauna had been exterminated, leaving the to just swarm the continents, eating and breeding. The other life was the algae-stocked oceans. The title "Bordered in Black" referred the black edges of all the continents where all the humanoids flocked to beaches to get at the only source of food.

Woe betide the spaceship that tried to land there. The humanoids swarmed them, climbing on top of each other by the tens of thousands, making flesh mountains like breaking storm waves. It was ghastly.

 

[PeroK]

Well, Aliens certainly exist in Sci-Fi novels. There's no doubt about that. Meanwhile, in the real universe ...

 

[DaveC426913]

Well, Aliens certainly exist in Sci-Fi novels. There's no doubt about that. Meanwhile, in the real universe ...

Yah Sorry bit of a tangent. I was riffing off the conjecture of what kinds of aliens we should expect to encounter. I think a realistic future scenario might be "Approaching Sirius B world Four. Oh look another algae world. Logged as Level 1 world, number 2,934,729. Going back to sleep".

 

[Algr]

Larry Niven wrote a short story "Bordered in Black" that, to this day, still haunts me. It was about a "food world" for an alien species consisting entirely of humanoids. Trillions of them - naked, tool-less without even houses; all flora and fauna had been exterminated, leaving the to just swarm the continents, eating and breeding. The other life was the algae-stocked oceans. The title "Bordered in Black" referred the black edges of all the continents where all the humanoids flocked to beaches to get at the only source of food.

I'm pretty good at technobabble explanations for sci-fi ideas, but this is hard to justify. Do the aliens eat sadism?

 

[Algr]

Yah Sorry bit of a tangent. I was riffing off the conjecture of what kinds of aliens we should expect to encounter. I think a realistic future scenario might be "Approaching Sirius B world Four. Oh look another algae world. Logged as Level 1 world, number 2,934,729. Going back to sleep".

Here is a question we won't know the answer to for a long time: For human settlement is an algae world better than a stone dead one? (Both with water). On the one hand, the algae would have created at least some free O². But what if there are 10,000,000 kinds of algae, and 1/1000 of them are deadly to humans?

 

[DaveC426913]

Do the aliens eat sadism?

What do you mean? The aliens didn't recognize the humanoids as sapient. It was no different from a cattle ranch or factory-farmed chickens.

*OK, there is one aspect that I left out: the aliens abandoned the world and it went feral in their absence. Still, the point remains: the humanoids didn't even have the tools or resources to make shelters.

 

[Algr]

The difference is that humans can take care of themselves and it would be far more efficient to let them do so. Also, if they have the technology to make it economical to transport meat from one planet to another, why use humans? Why not chickens or GMO mushrooms that taste just like human, but don't rebel or try to develop technology?

 

[DaveC426913]

The difference is that humans can take care of themselves and it would be far more efficient to let them do so. Also, if they have the technology to make it economical to transport meat from one planet to another, why use humans? Why not chickens or GMO mushrooms that taste just like human, but don't rebel or try to develop technology?

You'd have to read it and let the narrative tell you how it justifies its events. Admittedly, it's a short story in a larger Nivenesque universe, wherein the history and culture of the aliens is further explored.

Full disclosure: I self-reported my post 28, realizing that I dragged a (meta)science topic way off into sci-fi. Mods may delete or split thread at any time.