Is there life in the universe, and if so has it visited Earth?

[mikelepore]

Why would they visit us in person?

Since they're another species, we have no reason to expect them to have behaviors that seem to demonstrate "reasons" or "motives" to us, just as it makes no sense to us that salmon migrate the way they do, or mosquitos fly into flames. For example, perhaps the extraterrestrials have only one emotion and it is: "If you can possibly leave the world, then leave" -- and that has motivated everything else -- eat and reproduce in order to survive so that we can later leave -- invent tools and go through industrial development so that we can later leave. It doesn't have to make any sense to us. Our own set of reasons for doing things (scientific curiosity, aesthetic appreciation, sensation of comfort, sex drive, etc.) could be accidental and found only on earth. Space travelers anywhere in the universe only need to have evolved due to any reason whatsoever for becoming tool-makers with dexterous limbs and powers of abstraction. Their "why" might be incomprehensible to us.

I offer the same answer to those who ask, "If E.T. came here, why didn't it land at the United Nations and announce itself?" or "What would be the point of making a kaleidoscopic pattern in a cornfield?" The inquirer is projecting human motivations onto something that is not known to be remotely similar to human life. I give the same answer to Neil deGrasse Tyson, who doubts the existence of interstellar explorers who travel for many generations, because, he said, "Scientifically, we have a rule: you want to be alive at the end of your experiment, not dead." Yes, humans do, but we don't know that other intelligent beings think like us.

I don't assert that any of these things have actually happened. I'm only citing these examples to caution that the imputation of human motives to alien life would not be justified.

 

[shredder666]

I think its highly probable that aliens exist, but probably really far away.

Probability of alien life form existing in the universe would be, imho, irrelevant, because what are the chances of them developing means interstellar travel?

But if, in some science fictions... they travel on motherships, then I guess it would only be a matter of time before they enslave us..

 

[Ivan Seeking]

Probability of alien life form existing in the universe would be, imho, irrelevant, because what are the chances of them developing means interstellar travel?

That is an interesting question. Do we know?

If interstellar travel is possible but we just haven't discovered the required physics, it may be a near certainty that we have been or will be visited many times. On the other hand, it may be that we already recognize the limits of travel and the chance of visitations is zero. We can't really talk about the odds of a visitation unless we can calculate the odds that future discoveries will or could be made. So it seems to me that we can't know the odds [probability]; the range is 0 to 1.

 

[HarryDaniels]

On the subject of motives, assuming they would send a probe so many light years away from them, why? If we took this to a human motive for this, you could say it was for an energy source. If they could travel at the speed of light they would have to have a huge amount of to sustain the speed of light for four years or more. This would be impossible. The same rule would apply for an unmanned (or unaliened ;)) probe, they would still need a huge amount of energy.

Also, there are so many stars in the sky with so many planets orbiting them. How could the aliens find us, probe or not. I am not debating that aliens exist, if we looked at the figures, it is very likely for life to exist just in our galaxy, let alone the hundreds of millions of other galaxies. Though the likelihood of them reaching here is almost zero, and breaks many laws of physics as well as time. As I said in my last post, if they traveled at light speed for four years at the least, imagine how slow they would be going in time, if they decided to visit us when we were just becoming human, they may take four years in there perception, but they would take perhaps the human races lifetime to get here in our time. Its very unlikely.

And finally, no matter how incredible the ET life is, I very much doubt that it could break the laws of physics.
-Harry

 

[Ivan Seeking]

And finally, no matter how incredible the ET life is, I very much doubt that it could break the laws of physics.
-Harry

We just have to be careful when we invoke the "laws of physics". To which laws in particular do you refer?

Even with our undestanding of physics today, exotic forms of transportation, say in the form of a wormholes, for example, might be possible given enough energy. So do we mean the laws of physics or the practical limits of technology? Also, physics is not complete. We cannot state with certainty what limits do exist even within the existing framework. The recent interest in Heim's work is just one example of how quickly our perception of the possibilities can change. Suddenly we were talking about a practical hyperspace drive that could EXCEED the speed of light as viewed from our frame of reference, without violating the "laws of physics".

There are also ideas like the Alcubierre metric, or "Warp Drive".

 

[bobquantum]

Well, there are a hell of a lot of stars out there, so it is almost for sure that there is intelligent life out there. The problem is, the chance of them visiting a simple star system such as us out of a quadrillion other star systems is pretty mch close to nil.

 

[Ivan Seeking]

Well, there are a hell of a lot of stars out there, so it is almost for sure that there is intelligent life out there. The problem is, the chance of them visiting a simple star system such as us out of a quadrillion other star systems is pretty mch close to nil.

Is it? I can imagine scenarios that might motivate an alien species to investigate us. For one, perhaps life is rare. In that event, one might imagine advanced technolgies that allow alien scientists to find us. Note that in the time that I have moderated this forum, our ability to detect earth-like planets has improved dramatically. We are doing things now once thought to be impossible because scientists years ago could not imagine the electronics revolution and the resulting computing power now possible. How much better at this might we be in a million years? Also, life may be common, in which case we might expect to have neighbors [in galactic terms].

So how exactly do you calculate your odds?

 

[HarryDaniels]

Again, it is all relevant to energy and where would the energy to open a worm hole come from, assuming that they are real and can be opened. Where would this energy come from.

 

[Ivan Seeking]

Again, it is all relevant to energy and where would the energy to open a worm hole come from, assuming that they are real and can be opened. Where would this energy come from.

That is certainly a problem. That is why I pointed out that we may be talking about the limits of technology and not limits of physics. But I also look to potential cracks in the lining. Until the picture is complete [if a unified theory can ever be found], one can always argue that the door is open to discoveries that fundamentally change the game. The best example of this recently is probably the stuff related to Heims work.

I want to be clear that at best, Heim's work is under consideration, and at worst it may already be known to be hopelessly flawed. However, as the reports of his work emerged, the immediate potential ramifications of his theory were nothing short of astounding. In fact we saw NASA and two other agencies [I think the USAF was one] announce plans to test the concept. But the point is not to say Heim's work is relevant, rather that our expectations can change very quickly.

To the best of my understanding, according to one take on Heim's theory, it may be possible to shift a craft into another "space" in which the speed of light is relatively greater than in our space. Now I don't claim to understand the meaning of that, but that was the basic idea. I believe his theory provides for several higher dimensions that somehow allegedly makes this possible. It was also stated that one could artificially drive the speed of light to higher values in that space by adding energy to the engine or drive. By doing this, one could exceed the speed of light relative to our space while not exceeding the speed of light in the alternate space.

This is an example of how one might imagine a crack in the lining - a way around the problem of distance without violating the known laws of physics. The Alcubierre drive proponents seek to circumvent the speed of light limit in a somewhat similar fashion - by moving through a space that is moving through space [as near as I can recall, and whatever that means]. The point is not that any of these ideas will work, rather that we can already imagine ways that approaches like these might work.

Here is one old thread about Heim's theory. I want to stress again that I'm pretty sure that people have found problems with his work. It was believed by some serious scientists to be a unified theory.
https://www.physicsforums.com/showthread.php?t=106059

Even worse for those who do not favor this line of thought: Even with a unified theory, the possibility of future discoveries cannot be excluded.

 

[Ivan Seeking]

A correction to the statement about the alcubierre drive: The idea there is to contract space in the direction of motion while expanding space behind it, or something along those lines. Sorry, I have to be vague as I haven't reviewed this sort of thing for a long time. Here are a couple of threads about that subject.

https://www.physicsforums.com/showthread.php?t=255507
https://www.physicsforums.com/showthread.php?t=365753

I think I was describing how the warp drive operates on the Enterprise , but there are a few serious, exotic ideas, floating around.

 

[VooDooX]

http://www.esa.int/esaCP/SEM72XRJR4G_index_0.html

well it can defiantly travel thru space

 

[Dembadon]

I believe it would be unscientific to definitively claim 'yes' or 'no'. I believe "we don't know" is the appropriate answer to this question, at this point in time.

 

[DaveC426913]

I believe it would be unscientific to definitively claim 'yes' or 'no'. I believe "we don't know" is the appropriate answer to this question, at this point in time.

You miss the point of the thread.

As a poll, its intent is to get an idea of the opinions of individuals. The "I believe that..." is implicit in every vote.

 

[baywax]

http://www.esa.int/esaCP/SEM72XRJR4G_index_0.html

well it can defiantly travel thru space

This is a great article about some outstanding experiments... thank you VooDooX!

 

[Dembadon]

You miss the point of the thread.

As a poll, its intent is to get an idea of the opinions of individuals. The "I believe that..." is implicit in every vote.

*puts on his party-pooper t-shirt*

 

[GreenLantern]

my vote is on maybe maybe not but its more towards the Probably not.

If there is intelligent life with the technology to travel here then I'd just as much assume that there really isn't anything on Earth worth seeing. Chances are if they have the technology to travel here then they have seen way more interesting things than what exists on our rock (they probably have seen other Earth's even making ours that much less interesting)
just what I feel when comparing our little planet to the vast numbers of awe inspiring things that exist in the universe.
-GL

 

[qraal]

my vote is on maybe maybe not but its more towards the Probably not.

If there is intelligent life with the technology to travel here then I'd just as much assume that there really isn't anything on Earth worth seeing. Chances are if they have the technology to travel here then they have seen way more interesting things than what exists on our rock (they probably have seen other Earth's even making ours that much less interesting)
just what I feel when comparing our little planet to the vast numbers of awe inspiring things that exist in the universe.
-GL

My vote is for They're probably Out There - and They're probably here amongst us. As our surveillance technology shrinks and becomes more capable I think a reasonable extrapolation to ETIs much older than us would be that ETIs can monitor us without our knowing about it - any sighting or encounter would be deliberate not accidental.

But will They be composed of matter as we know it? Or is there another kind of embodiment?

 

[Ivan Seeking]

eh, okay, we aren't getting into "other kinds of ebodiments", whatever that means. Let's keep it real.

 

[qraal]

eh, okay, we aren't getting into "other kinds of ebodiments", whatever that means. Let's keep it real.

I didn't mean anything flakey. Just stuff like plasma structures, positronium, electromagnetic solitons, quantum-fields (which are real in some QM interpretations) and correlated structures in space-time foam. All physical, just non-baryonic.

 

[DaveC426913]

I didn't mean anything flakey. Just stuff like plasma structures, positronium, electromagnetic solitons, quantum-fields (which are real in some QM interpretations) and correlated structures in space-time foam. All physical, just non-baryonic.

In terms of life building blocks, those're flakey.

 

[Count Iblis]

Why would these beings with giant brains build machines that would turn on them? That seems dumb.

Initially, they won't turn on them. Economic competition combined with technological innovation leads to a Darwinian evolution of better and better designs of tools, machines, etc. If you compare this with biology, then the phase we are in today is similar to the primordial soup phase life was in more than 4 billion years ago. I.e. while the whole soup can maintain itself and is capable of growing, it does not contain autonomous parts that can grow and replicate themselves on their own.

Sooner or later this will change and you'll have the first single cell organisms. For the civilization, this means that you've automated an entire part of a production process, including maintaining and building of the factories. This will happen for obvious reasons: You can the produce astronomical quantities for certain goods at extremely low costs.

E.g. consider a small solar cell factory with an area of one square millimeter that makes a copy of itself every week. Then after just 1 year and four months, the whole Earth would be covered by these machines. You could think of sending one such machines to the Moon to convert part of the Moon to solar panels and capturing a significant fraction of the entire solar output of 10^26 Watt.

Once the technique of using self replicating machines is mastered, one can think of building astronomically large supercomputers that are capable of solving complex problems by brute force computation. You can then cook up optimal designs of extremely complex machines using genetic algorithms starting from nothing, including the production process which starts from the machines that already exists.


It is from here that machines with intelligence will arise. We know that human beings are essential in our economy. It is thus reasonable to expect that when you cook up the best design for a self replicating factory on such a giant supercomputer, you will typically get a design that includes artificial intelligence. Of course, only a huge supercomputer that is large enough to simulate the artificialy intelligent agents can arive at such a design.

 

[DaveC426913]

Initially, they won't turn on them. Economic competition combined with technological innovation leads to a Darwinian evolution of better and better designs of tools, machines, etc. If you compare this with biology, then the phase we are in today is similar to the primordial soup phase life was in more than 4 billion years ago. I.e. while the whole soup can maintain itself and is capable of growing, it does not contain autonomous parts that can grow and replicate themselves on their own.

Sooner or later this will change and you'll have the first single cell organisms. For the civilization, this means that you've automated an entire part of a production process, including maintaining and building of the factories. This will happen for obvious reasons: You can the produce astronomical quantities for certain goods at extremely low costs.

E.g. consider a small solar cell factory with an area of one square millimeter that makes a copy of itself every week. Then after just 1 year and four months, the whole Earth would be covered by these machines. You could think of sending one such machines to the Moon to convert part of the Moon to solar panels and capturing a significant fraction of the entire solar output of 10^26 Watt.

Once the technique of using self replicating machines is mastered, one can think of building astronomically large supercomputers that are capable of solving complex problems by brute force computation. You can then cook up optimal designs of extremely complex machines using genetic algorithms starting from nothing, including the production process which starts from the machines that already exists.


It is from here that machines with intelligence will arise. We know that human beings are essential in our economy. It is thus reasonable to expect that when you cook up the best design for a self replicating factory on such a giant supercomputer, you will typically get a design that includes artificial intelligence. Of course, only a huge supercomputer that is large enough to simulate the artificialy intelligent agents can arive at such a design.

It took you ten weeks to write that?

 

[qraal]

In terms of life building blocks, those're flakey.

Another CHON chauvinist!

 

[DaveC426913]

Another CHON chauvinist!

Never mind CHON, let's just start with atom-chauvinist for now.

 

[Ivan Seeking]

I didn't mean anything flakey. Just stuff like plasma structures, positronium, electromagnetic solitons, quantum-fields (which are real in some QM interpretations) and correlated structures in space-time foam. All physical, just non-baryonic.

Any such discussion is far too speculative for this forum. When it comes to possibilities within the range of knowledge, we always look to published material. We can entertain exotic ideas but only if we have a published paper.

 

[Count Iblis]

It took you ten weeks to write that?

I was too lazy to check for any replies in this huge thread at the time.

 

[Chronos]

ET is a tough nut to crack. The spaniards did not bother to conceal their arrival or presence in the new world. The were technologically superior, bent on conquest and exploitation, and rather easily subdued the natives of the new world. Any alien species capable of interstellar travel is obviously, and hugely more technologically advanced than us. We can only hope they do not share the spaniards objectives. A civilization so far advanced is likely morally advanced as well. Surely there are no resources on Earth they could not have derived from the untold number of planets whose paths they crossed during the journey here. As fairly smart critters in their own right, they would immediately recognize they discovered a very rare planet, found it interesting and are entirely capable of observing us without being noticed. That is the part that doesn't make sense - why UFO behavior is often weird and inexplicable. If they view us as ants, they would land wherever, whenever and do whatever they damn well pleased. If their intent is to covertly observe us, then their methods are naive, incompetent and bumbling at best. I wouldn't doubt we have been 'visited', I merely doubt they had any 'flat tires", or abandoned any crashed ships.

 

[qraal]

In some respects the technological distance between the Spaniards & the Amerinds really wasn't too great. At most a millennium, though the ideological dimension is hard to quantify.

ETIs OTOH may well be billennia ahead of us and there would be no reason why we'd even be aware of their monitoring. If they wanted conquest we wouldn't stand a chance. Tailored nano-plagues would suffice to send us all to a speedy extinction if so desired. 'Bug spray'.

Of course that assumes a monolithic effort by the ETIs. If this planet was contested by two different advanced groups, then perhaps they're locked into a dance of move/counter-move, leaving us none-the-wiser. Heaven help us if one gets the upper-hand...

 

[DaveC426913]

If their intent is to covertly observe us, then their methods are naive, incompetent and bumbling at best. I wouldn't doubt we have been 'visited', I merely doubt they had any 'flat tires", or abandoned any crashed ships.

Happens on Star Trek all the time.

I thought they nicely addressed it. There was an ep where they were observing a primitive race from a holo duck blind. Something failed and exposed them to the people. Much hijinks ensued.

I think the lesson is that even the most advanced civilization is not perfect.

 

[CEL]

Happens on Star Trek all the time.

I thought they nicely addressed it. There was an ep where they were observing a primitive race from a holo duck blind. Something failed and exposed them to the people. Much hijinks ensued.

I think the lesson is that even the most advanced civilization is not perfect.

I saw this episode and I agree with you that sh*t happens. But given the number of sightings of alleged alien spacecraft s, if the aliens are really covertly observing us, they must be incredibly incompetent.
In the Star Trek episode, after they failed to conceal their existence, Picard allowed one of the leaders of the primitive society to visit the Enterprise in order to provide sound information and end speculations of the existence of a powerful deity.
If aliens are visiting us and they know they have being detected, why don't they make overt contact?

 

[DaveC426913]

I saw this episode and I agree with you that sh*t happens. But given the number of sightings of alleged alien spacecraft s, if the aliens are really covertly observing us, they must be incredibly incompetent.

I don't know about that.

1] "incredibly incompetent" is a ratio. It's a ratio of successes vs. failures. Multiple failures combined with high competence means a very high number of attempts. The implication is that they are very active in observing us, such that the small fraction of failures result in a significant number.

2] We never forget. If, in the entire history of that race, the scientists had only failed failed twice, they'd remember them both forever.

3] And they'd be on knife-edge looking for more. Every ball of gas in a swamp, every shooting star, would be tossed into the fray as evidence, artificially building up the apparent size of the list.

If aliens are visiting us and they know they have being detected, why don't they make overt contact?

Why don't our own leaders admit they had sex with those underage girls?

You never admit. There is no up side to coming forth with the truth.

 

[Ivan Seeking]

But given the number of sightings of alleged alien spacecraft s, if the aliens are really covertly observing us, they must be incredibly incompetent...

If aliens are visiting us and they know they have being detected, why don't they make overt contact?

This is too speculative to be discussed. We have no way to anticipate the motives, capabilities, or sensabilities of any alleged alien species. If a species is mostly like us, then we might fathom a guess. But we have no way to know what an alien species might be like. So until I can at least understand the motivations of my cats, I'm not about to take on aliens.

At times we can't even explain the actions of humans.

 

[GODISMYSHADOW]

ET is a tough nut to crack. The spaniards did not bother to conceal their arrival or presence in the new world. The were technologically superior, bent on conquest and exploitation, and rather easily subdued the natives of the new world. Any alien species capable of interstellar travel is obviously, and hugely more technologically advanced than us. We can only hope they do not share the spaniards objectives. A civilization so far advanced is likely morally advanced as well. Surely there are no resources on Earth they could not have derived from the untold number of planets whose paths they crossed during the journey here. As fairly smart critters in their own right, they would immediately recognize they discovered a very rare planet, found it interesting and are entirely capable of observing us without being noticed. That is the part that doesn't make sense - why UFO behavior is often weird and inexplicable. If they view us as ants, they would land wherever, whenever and do whatever they damn well pleased. If their intent is to covertly observe us, then their methods are naive, incompetent and bumbling at best. I wouldn't doubt we have been 'visited', I merely doubt they had any 'flat tires", or abandoned any crashed ships.

I don't really know, but I'd like to think there has always been life.
Primitive seeds of life arrived on Earth from space billions of years
ago. From that simple beginning, Darwin's evolution took over.

 

[Ivan Seeking]

Note also that the question, "Has intelligent alien life visited earth?", does not assume that humans even existed at the time.

 

[Anticitizen]

I don't really know, but I'd like to think there has always been life.
Primitive seeds of life arrived on Earth from space billions of years
ago. From that simple beginning, Darwin's evolution took over.

Why would you choose to believe that? There's no evidence for it and it doesn't provide any answers about the origin of life.