Why Haven't Aliens Contacted Us Yet? (Fermi Paradox)

[flannel]

Could most life elsewhere have evolved to take nutrients directly from minerals and energy without the stage where some organism somewhere "decided" on the shortcut of consuming something else or feeding off of its corpse?

There's a fictional example of this in Project Hail Mary by Andy Weir (The Martian) where a 'microbe' in space 'lives' off the sun's energy.

 

[eburacum]

I can't stress enough that there are no planets that resemble Earth very closely among the 4000 planets already found, which suggests to me that human-like life is relatively rare.

We might find planets full of intelligent plant-like organisms, or intelligent crab-like organisms, or intelligent fish-like organisms, but they won't closely resemble anything we are familiar with, since their planets will be different to our own in many significant ways.

 

[Tunn11]

There's a fictional example of this in Project Hail Mary by Andy Weir (The Martian) where a 'microbe' in space 'lives' off the sun's energy.

There are also IIRC the Czill in Jack L Chalker's Well of Souls series who are intelligent plants but I don't know whether they fed on decaying organic matter. Hoyle's Black Cloud may qualify and various "energy" beings in Star Trek although the actual science/metabolism isn't clear in any of them.

Larry Niven has Earth type worlds as satellites of gas giants (Although radiation could be an issue) and we have an example in Titan with a methane/ammonia atmosphere. I don't know what current thinking on slow metabolism life is for worlds like this.
Would Triton (a probable Edgeworth Kuiper belt object) have an atmosphere if it was warmed up?

Of course Niven's answer to the Fermi paradox was a huge galactic scale war between the Slavers and Tnuctpun where they virtually wiped each other out leaving room for a second wave of intelligent beings who hadn't yet spread through the galaxy.

 

[eburacum]

One interesting consequence of life on a Titan-like planet, with a slow metabolism and low gravity, is that their slow metabolism would make gravity appear (to them) to act more rapidly. This would make their experience of life on a low-grav planet resemble our own experience more closely, although to an Earthling they would seem to be moving in treacle.

 

[Paul_Exeter]

Well then issue seems to be that 40 billion is still too far small a number to make intelligent life likely. I mean, what are the odds of life starting? What are the odds of multicellular life forming? What are the odds that intelligence evolves? What are the odds this all happens without extinction?

I guess with a set of one we don't know. Maybe it is so vastly unlikely that even 100 billion is far too small. Maybe its trillions to one. Who knows.

But since there is no clear evidence of any intelligent life anywhere at anytime, it seems more likely that its exceptional than common.

Edit: on a side note, regarding Morris argument, approx how many earth like planets are out there with both a gas giant nearby and an earth sized moon in their orbit? Both are necessary for him to have intelligent life.

I personally believe we will eventually find molecular life - living or fossilised - within our own solar system, seeded by comets:

"The ESA’s Rosetta spacecraft has found complex, solid organic molecules in dust particles coming off 67P/Churyumov-Gerasimenko, giving more weight to the theory that organic compounds and even life itself came from the stars"

https://www.borntoengineer.com/complex-organic-molecules-found-rosettas-comet

 

[Ronnie Jersey]

There are strange flying vehicles in our skies all the time, not saying that all of them are alien civilizations, but they are quite aware of this planet and have been watching us for some time. Whether they are from another dimension, another time, or another galaxy is the question.

 

[Delightful]

I personally believe we will eventually find molecular life - living or fossilised - within our own solar system, seeded by comets:

"The ESA’s Rosetta spacecraft has found complex, solid organic molecules in dust particles coming off 67P/Churyumov-Gerasimenko, giving more weight to the theory that organic compounds and even life itself came from the stars"

https://www.borntoengineer.com/complex-organic-molecules-found-rosettas-comet

For single celled life I think it inevitable. But intelligent life? I think if they were common we wouldn't be having this chat

 

[Delightful]

There are strange flying vehicles in our skies all the time, not saying that all of them are alien civilizations, but they are quite aware of this planet and have been watching us for quite time. Whether they are from another dimension, another time, or another galaxy is the question.

I dont know. I'm probably too sceptical. But maybe. I think it's be exciting to have nonhuman intelligence visit us. But I haven't yet seen anything that convices me that exists and is engaging with us.

 

[Ronnie Jersey]

I dont know. I'm probably too sceptical. But maybe. I think it's be exciting to have nonhuman intelligence visit us. But I haven't yet seen anything that convices me that exists and is engaging with us.

Once you see one of these strange vehicles, you cannot unsee it. That's a problem - and now I cannot discount the reports of others who have seen these things.
Thinking about it, the one I saw was in 1997, and that technology was unknown to us, and was also unknown back in 1947, when Kenneth Arnold saw those flying machines.
Also, how do we know that these things are not time machines? We don't, and we cannot catch them, their speed is phenomenal.

 

[Delightful]

Once you see one of these strange vehicles, you cannot unsee it. That's a problem - and now I cannot discount the reports of others who have seen these things.
Thinking about it, the one I saw was in 1997, and that technology was unknown to us, and was also unknown back in 1947, when Kenneth Arnold saw those flying machines.
Also, how do we know that these things are not time machines? We don't, and we cannot catch them, their speed is phenomenal.

I would love to have a close encounter.

 

[charliebrown]

Well Delightful,

In my younger days I had two major close encounters, and I realized a few things.

First, I know we are not alone.

Second, you start to wonder that it was really rare you had a chance to see this situation and wonder why me.

Third, no one will ever believe your story.

Fourth, seeing a UFO will not change your life or benefit you in any way.

Fifth, you will develop a weird depression from the experience.

 

[Delightful]

Well Delightful,

In my younger days I had two major close encounters, and I realized a few things.

First, I know we are not alone.

Second, you start to wonder that it was really rare you had a chance to see this situation and wonder why me.

Third, no one will ever believe your story.

Fourth, seeing a UFO will not change your life or benefit you in any way.

Fifth, you will develop a weird depression from the experience.

Where do you think the weird depression comes from?

 

[charliebrown]

I grew up in the 1950s in a poorer, more rural area of Nashville, Tennessee which is crazy because today because it is considered a richer area of Nashville.

My mom and I when I was about 11 years old saw a UFO at night on the lonely road to our house and she told me I could tell no one not even my father because people would think we were completely crazy.

That left me with a secret that left me looking at the world in a stranger way.

 

[Ronnie Jersey]

I grew up in the 1950s in a poorer, more rural area of Nashville, Tennessee which is crazy because today because it is considered a richer area of Nashville.

My mom and I when I was about 11 years old saw a UFO at night on the lonely road to our house and she told me I could tell no one not even my father because people would think we were completely crazy.

That left me with a secret that left me looking at the world in a stranger way.

I believe that there are many more ufo experiences and sightings than what we are aware of, because of all the ridicule and non-belief.
And it seems that these vehicles are more common in sparsely populated areas - I bet there are quite a few farmers and ranchers who have seen some odd things!

 

[Xanatic*]

Even if we assume such vehicles are zooming through the sky, seeing them more in sparsely populated areas might simply be due to lower levels of light pollution.

 

[charliebrown]

I kinda miss the rural area I lived in as a boy because at night I could see the Milky Way.

The seven mile trip to the nearest grocery and fuel station was really dark at night.

So, maybe that is why we don’t today notice UFOs at night is because of what Xanatic just said, bad light pollution.

With all the planes, drones, and light pollution as Ronnie Jersey said we just don’t notice all the UFOs wizzing by us.

 

[Paul_Exeter]

For single celled life I think it inevitable. But intelligent life? I think if they were common we wouldn't be having this chat

But it would act as a multiplier: that there are two distinct forms of life in just one solar system would make us have to recalculate upwards our estimates of life elsewhere .

However, if a life form in the deep soil of Mars (for example) was seeded from Earth or vice-versa it is perhaps even more exciting given it would be proof of panspermia

 

[Ronnie Jersey]

But it would act as a multiplier: that there are two distinct forms of life in just one solar system would make us have to recalculate upwards our estimates of life elsewhere .

However, if a life form in the deep soil of Mars (for example) was seeded from Earth or vice-versa it is perhaps even more exciting given it would be proof of panspermia

And if one - just one - of the many abduction cases (the Hills, Pascagoula, Allagash, etc.) is true, then we have to admit that we are not alone in the universe.

 

[Tunn11]

And if one - just one - of the many abduction cases (the Hills, Pascagoula, Allagash, etc.) is true, then we have to admit that we are not alone in the universe.

Or, we're not alone on Earth.

 

[eburacum]

However, if a life form in the deep soil of Mars (for example) was seeded from Earth or vice-versa it is perhaps even more exciting given it would be proof of panspermia

Panspermia is a complex subject. Life may be transferred between planets within a solar system quite readily; we have numerous meteorites from Mars and Venus on Earth, and presumably Mars and Venus both have meteorites which originated on Earth. So it seems possible that life may have transferred spontaneously between any or all of these three planets, and potentially between these planets and various moons, asteroids and comets within our system and vice versa. Indeed, I'd be very disappointed if this has not happened at some point in the long history of our star.

But the chances of transferring life between different solar systems is many orders of magnitude more difficult. Not only are stars very far apart and offer a very small target indeed for potentially life-bearing rocks, but the journey times between stars at typical meteoric speeds are very long indeed. This means that any lifeforms that might find themselves on an interstellar meteor would need to persist for many millions of years before approaching another solar system, making survival very unlikely. This sort of interstellar panspermia might happen on extremely rare occasions, but would probably not result in a galaxy filled with inter-related lifeforms.

One factor could increase the odds of interstellar panspermia; nearly all stars are created inside relatively compact molecular clouds which condense into stellar clusters. These stellar clusters disperse after a period of a few tens or hundreds of millions of years; but while the stars are still close together, life-bearing objects could transfer between their planets more readily. The problem with this is that most planets in young stellar clusters are hot and inhospitable., so this might reduce the odds considerably

Finally there is the possibility that advanced alien civilisations may have moved species around from star to star, which could rapidly increase the habitability of a galaxy by artificial means. I should point out that there is no evidence of this happening on Earth, since we can trace our molecular genetics back for around four billion years, but it may have happened elsewhere in the galaxy on a regular basis.