Do you think any aliens exist in the universe?

[aupmanyav]

I foresee worms that eat ziplocks, crocks, grocery bags, plastic peanuts, candy wrappers and dry cleaning bags, growing to tremendous size, emerging from the landfills and heading for town, protected by their lexan-like exoskeletons …

Won't that be nice?

There is a thing that amuses me more and more as I age. It’s how we humans are confident of our species’ survival to cosmic ages. I see no reason not to expect us to eventually number among the VAST majority of species - more than 99% of all species ever on earth - that are kaput.

Has not God created us for a special purpose .. to worship him. So, we will survive.

A bit of atheist fun. Won't it be nice if ice creme or kebabs become twice as large.

 

[aupmanyav]

Has not God created us for a special purpose .. to worship him. So, we will survive.

Well, NO. Humans created gods ... to scam other humans.

Aouth American will come closer to India.

You do know that map is of 250 million years AGO (in the past), right? Not where India will be in the future.
I'm thinking we'll be closer to the Mariana Trench in 250 million years.

Ah, you forget! God is testing us. That is why he had given us free-will.

Why would god test us? Doesn't he trust his handywork? Testing is what an imperfect mortal would do. god is too human to be a real god.

1. That is true for atheists, and not for theists.
2. Yeah I know, we were close to Africa and Madagaskar was practically a part of India (or vice-versa).
So easy to find on internet. The latest news is that Tibet may be breaking into two portions.
3. Fun, sarcasm for those who think so.

.

 

[Swammerdami]

Long ago I came across an interesting sci-fi story whose title I don't remember ("[Something] Andromeda" maybe?); I don't remember if it was a book or a movie.

Anyway, the enemy aliens have no intention of arriving at all. They just send a radio message which, when decoded, is detailed blueprints for a big computer system. The humans eagerly build this super-computer ... which turns out to be very powerful, in control of Earth and forcing the humans to build more copies of itself!

... Or something like that. Anyone know what my vague memory remembers?

 

[Elixir]

I foresee worms that eat ziplocks, crocks, grocery bags, plastic peanuts, candy wrappers and dry cleaning bags, growing to tremendous size, emerging from the landfills and heading for town, protected by their lexan-like exoskeletons …

Won't that be nice?

There is a thing that amuses me more and more as I age. It’s how we humans are confident of our species’ survival to cosmic ages. I see no reason not to expect us to eventually number among the VAST majority of species - more than 99% of all species ever on earth - that are kaput.

Has not God created us for a special purpose .. to worship him. So, we will survive.

Oh bullshit. Any old vertebrate can worship a god better than humans. Human worship is always undergirded by the fleeting awareness that god is a fantasy.

 

[Tannhäuser Rover]

Elon Musk talking about aliens:

1:39

I think it was Carl Sagan that said there either are a lot of aliens or none and they're equally terrifying

Elon Musk has also said he thinks we're probably in a simulation/video game:


Then there is this:

Exoplanet - Wikipedia

en.wikipedia.org

it can be hypothesized that there are 11 billion potentially habitable Earth-sized planets in the Milky Way

As a believer in the video game explanation my explanation for the apparent absence of aliens is to keep the costs of the video game low. I mean if you're looking at a typical distant star that apparently involves 10^57 atoms it can be approximated to us viewing it a lot more cheaply than if it had a Matrioshka brain attached or some nearby civilizations even though it might involve less than double the apparent atoms of the star on its own.

It is related to how likely evolution is. Either it is highly unlikely meaning that it rarely happens (e.g. once in the universe or our galaxy) or it is quite likely.... (or in-between)

My belief is that our simulation only started relatively recently and a virtual evolutionary history is worked out later on e.g.

View attachment 38724

Hello. This is my first post on this forum so I'm choosing a 'light' topic... I have often thought that maybe we are just part of a video game, with the alien version of a teenager playing SimUniverse II, or Planet Maker IV

On a more serious note, I always felt quite skeptic about the existence of Alien civilizations, and I always thought that the Drake Equation is flawed. However the sheer size of the Universe makes me conclude that, even if extremely rare, some Alien civilization probably does exist, or has existed, or it will. Current evidence suggests that the universe is flat, and considering the margin of error some astronomers have estimated that it is at least 250 times larger than the observable universe. Another estimate gives a minimum diameter of 23 trillion light years. That's a lot of universe... And it is not ruled out that it is actually infinite.

 

[pood]

I think the preponderance of empirical data is that it is probably spatially infinite, which means we ought to expect an infinite number of alien civilizations no matter how rare they are.

 

[WAB]

If there were no alien life forms in the universe other than on Earth, I would consider that more of a miracle than divine creation.

 

[Loren Pechtel]

I think the preponderance of empirical data is that it is probably spatially infinite, which means we ought to expect an infinite number of alien civilizations no matter how rare they are.

I'm not convinced it's infinite.

However, look at Earth. Life appears to have evolved as soon as conditions were tolerable. Something that happens fast is probably reasonably likely (given the time scale involved.) Is there anything stupendously unusual about Earth? No. (And note that Jupiter has been discredited--yes, it sweeps away some threats, but it creates more than it averts.) Thus the reasonable conclusion is that life should be abundant. Civilizations, though?

It took a long time for life to go from simple to more complex. While that does not say it's impossible it suggests that for many planets it might take too long.

It took a long time to go from more complex stuff to intelligence. Again, maybe time.

And there's a strong reason to think time might be relevant: We are at about the 99% mark on the time when Earth could develop an intelligent species. Soon CO2 will go as low as the plants can tolerate, the mercury will rise anyway, hugely favoring stuff with fast reproductive cycles.

But there's also the possibility that civilization destroys itself. Unfortunately, it certainly looks like that's going to be our fate.

 

[pood]

I think the preponderance of empirical data is that it is probably spatially infinite, which means we ought to expect an infinite number of alien civilizations no matter how rare they are.

I'm not convinced it's infinite.

However, look at Earth. Life appears to have evolved as soon as conditions were tolerable. Something that happens fast is probably reasonably likely (given the time scale involved.) Is there anything stupendously unusual about Earth? No. (And note that Jupiter has been discredited--yes, it sweeps away some threats, but it creates more than it averts.) Thus the reasonable conclusion is that life should be abundant. Civilizations, though?

It took a long time for life to go from simple to more complex. While that does not say it's impossible it suggests that for many planets it might take too long.

It took a long time to go from more complex stuff to intelligence. Again, maybe time.

And there's a strong reason to think time might be relevant: We are at about the 99% mark on the time when Earth could develop an intelligent species. Soon CO2 will go as low as the plants can tolerate, the mercury will rise anyway, hugely favoring stuff with fast reproductive cycles.

But there's also the possibility that civilization destroys itself. Unfortunately, it certainly looks like that's going to be our fate.

The evidence suggests it is flat at very large scales, which suggests but does not prove it is infinite. If it is not, it must have negative or positive curvature. However, all this would be way beyond the observable universe and is immune to verification or falsification.

I just read that it is now thought that the Hycean worlds probably are not water worlds as previously thought.

Who knows? But in a universe as vast as this, even if not infinite, there must at least be some inhabited worlds besides our own. Technological intelligence is a different matter.

But as noted in another thread, scientists say they have the clearest evidence so far of possible ancient Mars life, so we will see. I only regret I almost certainly will not live long enough to see extraterrestrial life confirmed.

 

[bilby]

Is there anything stupendously unusual about Earth?

It has a single very large moon.

https://xkcd.com/3135

 

[bilby]

But in a universe as vast as this, even if not infinite, there must at least be some inhabited worlds besides our own.

Sure; But it doesn't matter. Distance is as important as existence. A civilisation outside the observable universe is indistinguishable from non-existent.

And how close a civilisation needs to be depends on what our objective is. Mere detection is beyond our abilities for a civilisation more than a few tens of ly away, or for life (civilised or not) more than a few hundred*.

To interact with aliens (even by exchange of messages, not physical meetings) would require them to be practically on our doorstep - which restricts the number of possible locations so much that it is far from surprising that they aren't here. After all, we aren't there, either.







* Depending on how rigorous we feel the need to be. If we accept detection of water and O₂ as 'detecting life' we can do that at very long range; But bear in mind that Mars life is still neither confirmed nor disproven, and we are only 0.000005 ly away from that planet.

 

[Shadowy Man]

Is there anything stupendously unusual about Earth?

It has a single very large moon.

https://xkcd.com/3135

Even crazier is that that large moon has almost exactly the same angular size as the Sun as seen from the surface of the Earth in modern times.

 

[bilby]

Even crazier is that that large moon has almost exactly the same angular size as the Sun as seen from the surface of the Earth in modern times.

That makes for some impressive visuals once in a while, but I hardly think their importance can eclipse that of the tides.

 

[Shadowy Man]

Even crazier is that that large moon has almost exactly the same angular size as the Sun as seen from the surface of the Earth in modern times.

That makes for some impressive visuals once in a while, but I hardly think their importance can eclipse that of the tides.

But the question was what might be stupendously unusual about the Earth. the existence of a moon of that size may be unusual (we don't really know yet), but tides as a result are perfectly reasonable physical result.

However, the coincidence of the angular sizes seems quite remarkable to me, even if there are other Earth like planets with large moons, given that the distance between a planet and its singular natural satellite would seem to be a continuous possibility.

 

[bilby]

But the question was what might be stupendously unusual about the Earth. the existence of a moon of that size may be unusual (we don't really know yet), but tides as a result are perfectly reasonable physical result.

If current ideas about how the moon formed are correct, we should expect planets with oceans, and also with large moons able to cause large tides, to be fairly rare.

It doesn't seem like much of a stretch to hypothesise that large tides might be necessary for, or might massively accelerate, the movement of life from water onto land.

Land based life is likely a prerequisite for technology - even the most intelligent aquatic life is going to struggle to harness fire as a tool.

Our large tides provide a plausible reason to think that Earth might be the first planet within communications distance of here to develop civilisation, and therefore to explain why we see no other civilisations - they haven't arisen yet.

However, the coincidence of the angular sizes seems quite remarkable to me, even if there are other Earth like planets with large moons, given that the distance between a planet and its singular natural satellite would seem to be a continuous possibility.

Indeed. Though my "objection" was on two grounds:

1) The context of the discussion is the development of technologicslly advanced life, and the unstated criterion in @Loren Pechtel's post was that the unique feature should assist somehow in achieving that end. I am struggling to see how eclipses could assist with that, though once such a civilisation has arisen, they do make it much easier to study the Sun's corona.

And (much more importantly);

2) I needed to make some kind of pun, however feeble, on the word 'eclipse'.

 

[Shadowy Man]

But the question was what might be stupendously unusual about the Earth. the existence of a moon of that size may be unusual (we don't really know yet), but tides as a result are perfectly reasonable physical result.

If current ideas about how the moon formed are correct, we should expect planets with oceans, and also with large moons able to cause large tides, to be fairly rare.

It doesn't seem like much of a stretch to hypothesise that large tides might be necessary for, or might massively accelerate, the movement of life from water onto land.

Land based life is likely a prerequisite for technology - even the most intelligent aquatic life is going to struggle to harness fire as a tool.

If history has proven anything, it's that any ideas we have about this subject are based on very little evidence, and when evidence has come in it has been paradigm defying. When I was first getting into astronomy there were essentially zero confirmed exoplanets but there was a basic understanding of how a planetary system would form and why it would look like our Solar System. Now, those ideas are exceedingly quaint. So, I don't put a lot of stock in thoughts like "if current ideas about how the moon formed are correct, we should expect..." I think we need data and it's going to be a while before we have enough to make any kind of statistical assessment of moon sizes around earth-like planets. That's basically what I'm saying.

The idea that large tides may be *necessary* for the development of intelligent/technological life, seems even more of a stretch based on extremely little information.

However, the coincidence of the angular sizes seems quite remarkable to me, even if there are other Earth like planets with large moons, given that the distance between a planet and its singular natural satellite would seem to be a continuous possibility.

Indeed. Though my "objection" was on two grounds:

1) The context of the discussion is the development of technologicslly advanced life, and the unstated criterion in @Loren Pechtel's post was that the unique feature should assist in achieving that end. And (much more importantly);

Fair enough... I tend to drop into conversations without spending a lot of time reading all the precursor posts.

2) I needed to make some kind of pun, however feeble, on the word 'eclipse'.

having a compulsion to make a pun is tight!

 

[bilby]

The idea that large tides may be *necessary* for the development of intelligent/technological life, seems even more of a stretch based on extremely little information.

That's true, but unavoidable; By necessity all of our thoughts on the subject are highly speculative and woolly, and are more likely than not to be contradicted by future observations and data. It's hard to imagine a scenario in which moons like ours are common, though, however they may arise.

If they are, we have a slightly bigger mystery of why Mercury, Venus and Mars lack large moons to explain. Phobos looks like ephemeral junk, captured by Mars fairly recently and destined to become a meteor fairly soon; It's not even big enough to be approximately spherical. Deimos is even smaller. Mercury and Venus apparently lack moons completely.

Whatever process it is that makes big moons orbiting close to rocky planets, it didn't make one for three out of the four inner rocky planets in our solar system.

If our solar system is fairly typical, that strongly hints that such moons are at least moderately rare; And of course, if our solar system is highly atypical, then Loren's question doesn't arise at all.

 

[bilby]

Venus raises questions about how rare life might be too. It's a pretty close twin for Earth, but is obviously hostile to life (and frankly, to everything else). The assumption is that this is due to being just too close to the Sun, and therefore just outside the 'goldilocks zone'; But there may be more to it (indeed, it would be almost surprising if the complete explanation were so simple).

Does/did Venus simply have too much carbon to become a habitable planet, with a runaway greenhouse effect being a consequence that would still have occurred at a more Earthlike distance from the Sun? Could large tides have helped to scrub CO₂ from her atmosphere by increasing the rate at which the crust turns over through tectonic drift? Might such carbon sequestration have been a necessary part of Earth's early development to allow sufficient cooling for life to start - or to allow it to get going so early on?

The answers to these questions are probably "no". But we don't know that for sure.

And if any thread were ripe for wild assed speculations, surely this is that thread.

 

[Spacetime Inhabitant]

Elon Musk talking about aliens:

1:39

I think it was Carl Sagan that said there either are a lot of aliens or none and they're equally terrifying

Elon Musk has also said he thinks we're probably in a simulation/video game:


Then there is this:

Exoplanet - Wikipedia

en.wikipedia.org

it can be hypothesized that there are 11 billion potentially habitable Earth-sized planets in the Milky Way

As a believer in the video game explanation my explanation for the apparent absence of aliens is to keep the costs of the video game low. I mean if you're looking at a typical distant star that apparently involves 10^57 atoms it can be approximated to us viewing it a lot more cheaply than if it had a Matrioshka brain attached or some nearby civilizations even though it might involve less than double the apparent atoms of the star on its own.

It is related to how likely evolution is. Either it is highly unlikely meaning that it rarely happens (e.g. once in the universe or our galaxy) or it is quite likely.... (or in-between)

My belief is that our simulation only started relatively recently and a virtual evolutionary history is worked out later on e.g.

View attachment 38724

Hello. This is my first post on this forum so I'm choosing a 'light' topic... I have often thought that maybe we are just part of a video game, with the alien version of a teenager playing SimUniverse II, or Planet Maker IV

On a more serious note, I always felt quite skeptic about the existence of Alien civilizations, and I always thought that the Drake Equation is flawed. However the sheer size of the Universe makes me conclude that, even if extremely rare, some Alien civilization probably does exist, or has existed, or it will. Current evidence suggests that the universe is flat, and considering the margin of error some astronomers have estimated that it is at least 250 times larger than the observable universe. Another estimate gives a minimum diameter of 23 trillion light years. That's a lot of universe... And it is not ruled out that it is actually infinite.

It was Arthur C. Clarke who created the quote:
"Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.”
Personally I believe ET life is common, based on the Copernican Principle.

In regard to the Drake Equation, I read a book in the 1990s, which was a collection of articles by scientists involved in CETI and SETI. In one chapter the author discussed the Drake Equation and concluded that most of the factors cancel out leaving. N = L.
I also own a book by Frank Drake & Dava Sobel called "Is Anyone Out There? The Scientific Search for Extraterrestrial Intelligence", along with other books on this, as it is a topic of much interest to me.

 

[bilby]

In regard to the Drake Equation, I read a book in the 1990s, which was a collection of articles by scientists involved in CETI and SETI. In one chapter the author discussed the Drake Equation and concluded that most of the factors cancel out leaving. N = L.

Well, L (the length of time for which [technological] civilizations release detectable signals into space) may be very short indeed.

The assumption that any sufficiently advanced technological civilisation would be increasingly "radio loud" seemed very reasonable in 1961, when radio signals had been increasing in power exponentially since the first Marconi sets, but technology has moved on.

TV and communications are now transmitted by cable or fibre-optic rather than radio; The leaking of radio frequency radiation to space is dramatically reduced since the mid-C20th, and is still falling. The radio we do still transmit is increasingly low power, purely because new technology allows it to be less wasteful.

Radio is increasingly old hat; Listening for alien radio might be as outdated as trying to spy on the US Army by tapping into their telegraph wires.

The only human radio signals likely to be strong enough to detect at several lightyear's range (should an alien be listening for them) are the Distant Early Warning (DEW) radar signals from the Cold War era. We broadcast these between 1957 and 1988, at which time the system switched to phased array radars with much lower power, and much narrower sweep; The new signals were more effective at the ranges required, but wasted far less power into deep space.

If L for humans is estimated at 30 years, and the Copernican principle applies, then we would be very lucky to spot even a fairly nearby civilisation.

I envisage a future in which a bug-eyed being on a planet orbiting Tau Saggitarii, clutching in one tentacle a printout from a radio telescope that was pointed at Sol in 2097, with the DEW radar pulses encoded as 6EQUJ5, and the tentacle scrawled annotation "Wow!"

Despite finally securing more radiotelescope time in the year 2130, no further such signals have been detected from the Sol system, leading most bug-eyes to write this signal off as random noise, or (on the other tentacle) perhaps interference from a local Saggitariibound transmitter.