# Intelligent alien life



## The_African (Jun 27, 2010)

Even if there is only a .01% chance of there being other intelligent life in the universe, with billions of habitable planets, wouldn't it be inevitable?

edit : I was going to post an article but I can't do that with less than 15 posts. Anwyays, do you think Earthlings are alone in the universe?


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## Doctor Crankenstein (Jun 27, 2010)

The .01% arbitrary figure is a bit unrealistic to me, I realise that you only came up with it for the purpose of the thread but anyway. 

Scientists have discovered a great number of planets and moons in the 'Goldilocks zone' that they believe are capable of supporting life. If there is such a large number of these planets capable of supporting life it's a logical conclusion that some of them do. 

I can't comment on the credibility of the following because I only saw the news reports, I didn't look at any research or journal articles but: Hasn't NASA discovered evidence of microscopic bacteria that use to exist on Mars? There is also talk of the possibility of the oceans on Jupiter's moons having life. If there is "evidence" of life other than earth in just our solar system imagine what we could find in just our galaxy let alone the entire universe. 

Just to get in before someone brings it up; current scientific consensus is that the universe is not infinite (See steady state theory) so the argument that because the universe is infinite all probability limits approach 1 is flawed. 

I know your question specified Intelligent life but the 'seed' of any life whatsoever would be enough to potentially develop into intelligent life. It also depends upon your definition of intelligence. What qualifies as intelligent life? People argue that dolphins, pigs, dogs etc. are Intelligent. Would this sort of qualification apply to alien life as well? 

It also depends upon what counts as life (The Hooloovoo from Hitchhiker's Guide to the Galaxy comes to mind). Alien implies just that... Alien. 

The 15 post limit sure is irritating... I wanted to post in the photo  competition but...


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## Urien (Jun 27, 2010)

There is, alas, as of yet no evidence of life anywhere else but Earth. 

In other words we have as of yet no sample set to realistically assess the frequency of life on other worlds.

However, we do have a little of a sample set to speculate about intelligent life on other worlds. We as intelligent life have sent out spacecraft as well as signatures of intelligent life (radio waves, tv transmissions). Other intelligent species over the long span of billions of years might do the same. We have found no evidence of intelligent alien life, no artifacts, no satellites, no transmissions... where is everybody? This is known as the Fermi Paradox...

Fermi paradox - Wikipedia, the free encyclopedia

Imagine how many probes humanity will be sending out in say two hundred years, small, near light speed, and possibly self-replicating. The galaxy would be aswarm with out signiture... so far we've found nothing.


There are reasons (see article) why this may be so, however, no alien presence is perhaps a small piece of evidence arguing against intelligent life in the galaxy.


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## Starbeast (Jun 28, 2010)

*Photographs of the same object which changes direction, shape and turns on lights*​ 







 
*U.F.O.s captured on Infared - object exits the wooded area after 4 mins.*
*Notice how well the objects mimic our aircraft by utilizing blinking lights*​


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## Karn Maeshalanadae (Jun 28, 2010)

You have to realize that "intelligent" life does not necessarily have to be on par with ours-it could be there's a race out there in an era identical to our Medieval era, a race that wouldn't be able to respond to human-sent probes.

And as far as this "goldilocks" zone thing, that's crap too, in my opinion. The mistake human scientists are making is that any race out there would be in any way similar to us. We evolved the way we did because our planet became the way it did. It could be that there are races out there that have evolved to withstand temperatures of -400 degrees Fahrenheit or 600 degrees Fahrenheit, races that have evolved to breathe methane or carbon dioxide rather than oxygen, races like that in the movie Signs-remember how water was damaging to the aliens?

Human scientists need to get their arrogant heads out of their arrogant rears and consider the possibility that just because there aren't very many "Earth-like" planets out there doesn't mean that there isn't a possibility of an intelligent life form drastically different than our own.


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## Doctor Crankenstein (Jun 28, 2010)

> You have to realize that "intelligent" life does not necessarily have to  be on par with ours-it could be there's a race out there in an era  identical to our Medieval era, a race that wouldn't be able to respond  to human-sent probes.



That's exactly the point I was trying to make by questioning what qualifies as intelligent.



> The mistake human scientists are making is that any race out there would  be in any way similar to us.



Again, Hooloovoo's.

The talk that there has been about the possibility of silicon being the basis for life instead of carbon has been quite interesting.


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## J Riff (Jun 28, 2010)

There must be millions of them out there, but perhaps we missed them by a few million or billion years, which is the blink of an eye, cosmically.


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## ktabic (Jun 28, 2010)

Karn Maeshalanadae said:


> You have to realize that "intelligent" life does not necessarily have to be on par with ours-it could be there's a race out there in an era identical to our Medieval era, a race that wouldn't be able to respond to human-sent probes.



But for the purposes of communicating with them, across interstellar distances, they need to be at at least our level of technology. And quite close to us (distance wise). A planet that supports life with the technology of 100 years ago would appear very similar to a planet with the technology of 100 million years ago, when viewed from a different star altogether.



Karn Maeshalanadae said:


> And as far as this "goldilocks" zone thing, that's crap too, in my opinion. The mistake human scientists are making is that any race out there would be in any way similar to us. We evolved the way we did because our planet became the way it did. It could be that there are races out there that have evolved to withstand temperatures of -400 degrees Fahrenheit or 600 degrees Fahrenheit, races that have evolved to breathe methane or carbon dioxide rather than oxygen, races like that in the movie Signs-remember how water was damaging to the aliens?



Goldilock zones are perfectly fine. All it means is that there is the possibility of liquid water on the surface of a planet. And that increases the chance that the surface can support lifeforms that require water. Such as carbon-based life. And currently that is the only type of life we would be able to detect without going there. The goldilock zones certainly aren't a hard and fast rule, and I doubt you could find a planetary scientist who would claim it is, but they are a starting point. And we are only just starting. 
As for the other types: -400F is 33K. Chemical reactions at that temperature would be virtually non-existent, not a good indicator for life. At 315C (600F) reactions are likely to be to energetic. This doesn't mean that life can't exist at those temperatures, just that we don't know enough about those extreme environments to know what can't and can't happen there. #
We have already speculated on methane based life, and are in a symbiotic relationship with carbon dioxide breathers (we call them things like trees, grasses, flowers. Stuff like that). 
As for Signs, if they where so sensitive to water, why where they running about unprotected in an atmosphere with water vapour in it?



Karn Maeshalanadae said:


> Human scientists need to get their arrogant heads out of their arrogant rears and consider the possibility that just because there aren't very many "Earth-like" planets out there doesn't mean that there isn't a possibility of an intelligent life form drastically different than our own.



1: The number of 'Hot Jupiter' planets that have been found is not an indicator that 'Earth-like' planets are rare, but an indicator that our current planet-hunting systems are only really good at detecting Hot Jupiters. Over the next decade or so, there will be several new planet-hunting systems going online, and they will be much better at finding Earth-likes. Once they are online we will get a much more accurate picture of the distribution of planets.

2: Scientists are fully aware of the fact that life can exist in considerably different forms than out own. But it is really difficult to detect life in forms we are not used to and the concentration on carbon-based life is simply a matter of practicality. We know the signatures that are left by carbon-based life, and with decent detection equipment (same as above) we should be able to detect planets with carbon-based life out to a couple of hundred light-years*. The possible methane-based life on Titan has been detected, not by encountering alien life, but by a abnormal level of chemicals. And that is the only way we currently have to detect life. Until we go out there and start exploring, these signatures are the only thing we have to help us detect life. And to detect the really exotic, like giant sentient gascloud, it need to do something that an ordinary giant gascloud wouldn't do.


*It will take a really long time to take a look at each of the stars in range, detect if there are planets in the right place and then look for the signatures. This is decades long work.


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## ktabic (Jun 28, 2010)

Doctor Crankenstein said:


> The talk that there has been about the possibility of silicon being the basis for life instead of carbon has been quite interesting.



Silicon (given it's position in the periodic table) reacts similarly to carbon in many ways. So it can form a silicon based variation of many carbon based chemicals. This is why it keeps coming up as a possible alternate basis for life. But all the chemical reactions would require a higher level of energy to complete. There are quite a few things silicon life would have to do differently (from a chemical pov)


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## Doctor Crankenstein (Jun 28, 2010)

J Riff said:


> There must be millions of them out there, but perhaps we missed them by a few million or billion years, which is the blink of an eye, cosmically.



The area of space we have searched is ridiculously small. That's why the "well, we haven't found them yet" argument is so absurd to me...


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## The Procrastinator (Jun 28, 2010)

Doctor Crankenstein said:


> The area of space we have searched is ridiculously small. That's why the "well, we haven't found them yet" argument is so absurd to me...



Me too  Apart from the big space issue we are barely beginners at this stuff, technologically I mean (this was mentioned above by someone else as well). Cripes, I'd be shocked if we did find something and I dare say I wouldn't be alone!

Btw a big HELLO to Starbeast and a request for a favour. My internet connection is such that I can't view videos unless I have a spare hour or so to wait for each one to load - I know I'm stuffed with the pretty picture ones, but any chance of a really brief summary of the one that said something? Anyone?


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## Starbeast (Jun 28, 2010)

*Intelligent Beings from Elsewhere*



The Procrastinator said:


> Btw a big HELLO to Starbeast and a request for a favour. My internet connection is such that I can't view videos unless I have a spare hour or so to wait for each one to load - I know I'm stuffed with the pretty picture ones, but any chance of a really brief summary.


 
A Gargantuan Good Morning to you *The Procrastinator,* I'm more than happy to help you with info on the videos.


1. *Prof. Michio Katu*, talks about how little effort is given to search for other intelligent beings out in space with our primitive technology. We could be recieving signals right now, and not even know it. And a super advanced races in space may not even bother with us because we are so primitive.

*Starbeast's comment:* However, NASA and others connected to space programs (etc.) have been ordered to keep quiet about the emense activity with outworlders passing by and traveling to Earth. Fortunately other countries are beginning to be more open about what is really going on near and on our world (past & present).

2. *STS-88 photographs,* an astronaut snapped pictures over Africa of a strange black craft that could change its shape and switch on and off its lights as it zig-zagged in the lower atmosphere.

*Starbeast's comment:* This type of craft could be a piloted vessel or a remote controlled probe. A UFO like this, that is seen from a distance can appear to look like a common aircraft and go unnoticed. Some of these UFOs have been known to change color and display blinking lights that mimic planes, jets and helicopters. However, these UFOs still exhibit telltale signs that they are not common aircraft, such as being silent (no engine noise), hovering, moving at incredible speeds and (if you're lucky to spot one) weird shapes.

3. *Infared Footage,* some indiviuals now-a-days use INFARED devices to watch the sky for UFO activity, because some of these outworld ships can not be seen with the naked eye. The woman who recorded this footage had been observing a wooded area near her home and decided to prove to her friends that she was not imaging UFOs. In this video, you can see a UFO hovering inside of the woods, then it rises out and becomes really bright (orange/amber in color by the naked eye). Afterwhich it slowly flys off without making a sound and begins to blink like an airplane, even though you can clearly see that it doesn't have a shape like an airplane. Plus she also recorded a hovering craft (which was very close) without using infared and you can see it switch on multiple small lights and it starts to blink them like a common plane.

*Starbeast's comment:* Keep your eyes in the sky (night or day), because you never know what you might be fortunate to see.


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## ktabic (Jun 28, 2010)

*ktabic*'s comment on the above. 
Like NASA and the US Government could cover up UFO sightings world wide. Can't happen. For starters, there are 100000 amateur astronomers in the US alone. Any coverup would have to involve all of them.
Which is another thing. There are 100,000 amateur astronomers in the US alone. Must be in the millions, world-wide. They spend almost every clear night outside watching the sky. They are some of the best observers in the world. Many of them are better telescope astronomers than the professional astronomers. Yet I've never heard of one serious amateur astronomer ever claim to have seen a UFO. Massive world-wide cover-up? Or just nothing to report?


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## Starbeast (Jun 28, 2010)

*UFO Mysteries*

*ktabic's comment:* There are 100,000 amateur astronomers in the US alone. Must be in the millions, world-wide. They spend almost every clear night outside watching the sky. They are some of the best observers in the world. Many of them are better telescope astronomers than the professional astronomers. Yet I've never heard of one serious amateur astronomer ever claim to have seen a UFO. Massive world-wide cover-up? Or just nothing to report?


*Starbeast's reply:* I used to think the same things, until I spoke privately with some professional astronomers. Off the record, they told me UFOs sometimes disrupt their star surveys, or they think it's an incoming comet or meteor and jump out of their chairs thinking that they have to warn someone about it. But they all told me that none of them can say anything about common UFOs flying around or they could lose their jobs. I even interveiwed people who work at airports for traffic control and pilots, but they all tell me they have to keep quiet about it too. Not long ago O'hare airport in Illinois had a sighting of three UFOs hovering over their runways and pilots who saw them were instructed not to speak to anybody, but some did anyways because there were alot of witnesses to back them up.

I still see a few UFOs (night and day) from time to time and I'm not even looking for them. Close friends of mine who told me that they don't believe in aliens and that they's have to see a UFO in order to believe that something is really going on. Are now approaching me with wide-eyes and fear telling me that they saw something that they couldn't explain. One friend of mine (who was a complete sceptic) told me that his youngest daughter called him over to ask him what is hovering a few feet over their garage. So he and his family went outside to watch a slowly revolving disk float quietly over rooftops and trees, then it took off into the sky.

Like I said, keep an eye in the sky, because you never know what you might see. But even if you do see something, most people aren't going to believe you anyway, that's why I just keep it to myself.


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## Karn Maeshalanadae (Jun 28, 2010)

About the UFO comment-since when did the term "UFO" automatically imply aliens?


UFO stands for "Unidentified Flying Object". That could imply anything within the sky-a comet, meteor, under-wraps aircraft, anything, even weather balloons. It does NOT necessarily mean alien spacecraft.


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## jojajihisc (Jun 29, 2010)

J Riff said:


> There must be millions of them out there, but perhaps we missed them by a few million or billion years, which is the blink of an eye, cosmically.



I agree. And if it isn't time it's distance. Even if we had millions of probes traveling through the galaxy there is ample room for them to be missed, plus this scenario is limited to a single galaxy, where we may indeed be the only intelligent life in existence at this time, when there are billions of galaxies out there.


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## Doctor Crankenstein (Jun 29, 2010)

I was about to say exactly the same think Karn.


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## Starbeast (Jun 29, 2010)

*Intelligent alien life?*



Karn Maeshalanadae said:


> About the UFO comment-since when did the term "UFO" automatically imply aliens?
> 
> UFO stands for "Unidentified Flying Object". That could imply anything within the sky-a comet, meteor, under-wraps aircraft, anything, even weather balloons. It does NOT necessarily mean alien spacecraft.


 

Sorry, I should have been a little more clearer. For me, a light in the sky that is very far away is really difficult to determine what it is, and they can be easily dismissed. But when I refer to UFOs, I'm talikng about definate shapes that you can make out, I'll give you a couple examples -


In the early 1980's and just after the sun went down, my dog and I were standing outside my home on a clear starry night. Suddenly I hear a hissing noise, like gas under pressure escaping, then I heard it loudly above me. I look up and the lights from the houses illuminate a jet black disk (or saucer if you like) with no markings slowly and silently gliding over me at telephone pole level, it was sixty feet wide. I then noticed two gas plumes blasting out the backside of it (on and off repeatedly), and I heard it come out (the hissing sound). The saucer began rising fast the moving quickly toward the south, it began to glow in a yellow/orange color then bolted out into the sky.

In the 1990's, I was at a relatives home one sunny afternoon, and she was watching two children of a friend of hers that day, I noticed that the kids were drawing multicolored upright eggs. I said to them "Oh, making colorful Easter eggs, very cool." But they told me that they both saw this colorful egg shaped object that was big as a house floating near the edge of the yard only a half an hour earlier when they were both playing outside. It was rolling its colors over itself like in waves, but when my relative called them for lunch, it became like a reflective mirror and flew away really fast without a sound.

I would say that these objects demonstrated some kind of otherworldly intelligence behind them, be they piloted or remote crontroled.

I hope Karn Maeshalanadae and Dr Crankkenstein that these small examples give you both some clarity of what I've been investigating for some time now.


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## Karn Maeshalanadae (Jun 29, 2010)

They of course do, Starbeast. What I was talking about wasn't just your own experiences, but the fact that as soon as anyone hears the term "UFO" they automatically assume it to involve aliens. It doesn't.

That's all I meant.


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## Doctor Crankenstein (Jun 29, 2010)

Same. I wasn't having a go at you either SB


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## ktabic (Jun 29, 2010)

*Re: UFO Mysteries*



Starbeast said:


> I used to think the same things, until I spoke privately with some professional astronomers. Off the record, they told me UFOs sometimes disrupt their star surveys, or they think it's an incoming comet or meteor and jump out of their chairs thinking that they have to warn someone about it.


Thats interesting. The professional astronomers that taught me (and I'm sure the next group that will be teaching me next year) all failed to mention UFOs as things that can disrupt their work. On a professional or amateur level. Even in the part of the course where they where covering things that can interfere with with observations. And seeing as how they where training amateur astronomers who where and are working towards formal qualifications, you would have though they might have mentioned UFOs and how we aren't allowed to talk about them. But they didn't. Strange that.



Starbeast said:


> But they all told me that none of them can say anything about common UFOs flying around or they could lose their jobs.


I could say several things about this. But it wouldn't be kind of me. So I will hold my tongue.



Starbeast said:


> Not long ago O'hare airport in Illinois had a sighting of three UFOs hovering over their runways and pilots who saw them were instructed not to speak to anybody, but some did anyways because there were alot of witnesses to back them up.


And amazingly, despite being one of the busiest airports in the world, with 175000 passengers a day, not one of the many witnesses had a decent camera. Or video. Amazing.



Starbeast said:


> Are now approaching me with wide-eyes and fear telling me that they saw something that they couldn't explain.


Do they regularly watch the sky? Are they familiar with very many atmospheric phenomena? Or what the sky at night, or even during the day, really looks like? Or what happens when the two intersect? I doubt it some how.



Starbeast said:


> Like I said, keep an eye in the sky, because you never know what you might see. But even if you do see something, most people aren't going to believe you anyway, that's why I just keep it to myself.


Oh I do keep an eye on the sky. Quite a lot more than most people. And I have seen some amazing and spectacular things. But not UFOs.


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## Urien (Jun 29, 2010)

I think alien spacecraft ineptly disguising themselves and buzzing Earth is highly unlikely. Millions of cameras, videos these days and still no incontrovertable or even particularly convincing evidence.

To believe this we have to assume: aliens are incompetent; by some anti-miracle no effective imagery has been recorded and more unlikley still, a worldwide conspriacy involving pilots, airport staff, astronomers and government.

Sorry doesn't stack up for me.


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## Doctor Crankenstein (Jun 29, 2010)

> aliens are incompetent



have you seen race to witch mountain? lol...


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## goldhawk (Jun 29, 2010)

*Re: Intelligent alien life?*



Starbeast said:


> I look up and the lights from the houses illuminate a jet black disk (or saucer if you like) with no markings slowly and silently gliding over me at telephone pole level, it was sixty feet wide.



I sorry but you can't judge distances without a reference.  You can't tell how far away an object in the sky is unless there is something nearby that gives you a scale.  Binocular vision only works for about 6 feet.  To judge distances beyond that you need something like a person, a car, or house to give you the relative size.  If you're in a place where there's no relative feature, like the desert, the Arctic, or Antarctic, then you can judge distances.  People in the Arctic look at a mountain range and thinks it's only 30 miles away but in truth it's over a hundred.  People have been fooled by realistic model planes, thinking they're the real thing thousands of feet overhead when in truth they're just hundreds of feet.  You just can't judge how far away things are in the sky.


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## Doctor Crankenstein (Jun 29, 2010)

but surely telephone pole height is well within the distance of working spatial perception.


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## goldhawk (Jun 29, 2010)

Doctor Crankenstein said:


> but surely telephone pole height is well within the distance of working spatial perception.



Only if the object passes *under* the wires.  If it passes over them, you don't know how far away it is.


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## Starbeast (Jun 30, 2010)

*Intelligent alien life? You figure it out.*



goldhawk said:


> I'm sorry but you can't judge distances without a reference. You just can't judge how far away things are in the sky.


 

I was trained in the military to spot aircraft and judge distance, however the black saucer was close enough to throw a rock at it and hit it easily. It was as big as a house drifting over my head.

I feel I've said enough, I don't want to say anymore......(nothing personal to anyone)

Thanks for the reply Karn and Crankenstein


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## Doctor Crankenstein (Jun 30, 2010)

What did you do in the military?


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## Dave (Jun 30, 2010)

He could tell you but then he would have to kill you! 

Maybe the aliens metabolism means that they move at tens times the speed as us, like that original Star Trek episode 'Wink of an Eye'.

Seriously, our definition of 'Intelligent' may be too earth-centric when we finally meet other forms of life. The universe is so large and old that the odds say there must be other forms of life in it, but:

1) Is it already extinct.
2) Is it close enough to meet us.
3) Can we actually communicate with it if we do? (maybe they are just too different for us to understand each other.)

If it is like us, I'd like to think we/they would come in peace, but as Stephen Hawking recently pointed out, our best analogy would be the Spanish meeting the Aztecs. Even if there is no competition over resources and land for colonisation, there will be new diseases to share.


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## Doctor Crankenstein (Jun 30, 2010)

> there will be new diseases to share.



Not if they are silicon


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## Dave (Jun 30, 2010)

True, though seriously, if Silicon could build polymers like Carbon can I think we would see them naturally on Earth. We do see complex Silicon molecules and they are called Rocks. Despite old Star Trek episodes, you can watch them for a long time without them moving very far.

The other possible chemical substitution that is discussed is liquid Ammonia as a solvent instead of Water. That would be a seriously cold world in which I doubt we could survive ourselves.


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## J-WO (Jul 1, 2010)

I'm pretty sure there has to be intelligent alien life out there. And I can't rule out the possibility some civillisation has figured out FTL. Who can say?
But what I can't figure out is that, if the above is true, why would any vessel have to enter Earths atmosphere to investigate? A culture that can travel faster than light could probably read my DNA from the comfort of Pluto's orbit, surely.


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## J Riff (Jul 2, 2010)

Right, J-Wo. And the idea  that Aliens would even come here personally is questionable.. they would send beings grown in vats, to go pick up whatever it is they wanted. What could they want here? They can probably connect to the internet and watch TV from Proxima Centauri and learn that there is nothing worth coming here for.


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## J-WO (Jul 2, 2010)

_Glee_ has probably made us the pariah of the Milky Way.


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## Dave (Jul 2, 2010)

Or, too far away from the hyperspace bypass for anyone to bother turning off!


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## skeptical (Jul 4, 2010)

A few years back, I carried out a simple exercise.  I was interested in the question of how long it would take humanity to totally colonise the Milky Way galaxy to the point of overpopulation.

The answer depends on the assumptions you put into the model.   I assumed no FTL travel, but a cruising speed between stars of 0.2C.  I discovered that population growth was not limiting.  The times involved were so great that population size would grow more than enough.  I also assumed that, if a star system had no habitable planets, humans would simply build artificial habitats in space, such as giant rotating cylinders, using local raw materials.  Thus, my assumption that expansion was not limited by planets available.

The answer, depending on assumptions, was somewhere between 400,000 years and 10 million years.

The shortest time (400,000 years) was based the assumption that humanity went bananas and devoted itself to little more than expansion.  This would be achieved by sending billions of probes at 0.2C to all corners of the galaxy.  Each probe would contain frozen embryos and advanced robots able to create new habitats, and thaw, and educate the embryos.

Anyway, back to aliens.   This gives us a time scale for alien expansion, also.  If we postulate just* one* alien species in our galaxy that is aggressively expansionist, then it would colonise the entire kaboodle within 10 million years.  This time is a mere eye blink against the age of the galaxy.

Hence the Fermi Paradox.   Where the hell are they?

Simplest answer is that advanced life forms are sufficiently rare that no such aggressively expansionist species has evolved in our galaxy.


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## jojajihisc (Jul 4, 2010)

The main problem I have with the Fermi Paradox is that, as Robert A. Freitas Jr. states, the paradox 



> implicitly construes the absence of extraterrestrials on Earth as positive evidence of their nonexistence



A bigger problem is that we at least know that intelligent life does exist in one place so it seems more likely it should exist in another than not at all.


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## skeptical (Jul 4, 2010)

joja

The Fermi Paradox is a question, not an implication.   There are numerous suggested answers, none of which we can test.   I have suggested that the most likely answer is that intelligent aliens are rare.  I did not say they don't exist.

However, with 200 billion star systems in the Milky Way, and a lifetime of 5 to 7 billion years, if aliens were common, there seems no reason why they would not have visited our solar system, and settled here.

Outside the Milky Way galaxy, there are more galaxies than we can even estimate in number with any accuracy, but at least hundreds of billions.   Even if intelligent aliens are rare, they almost certainly exist there.   

The thing is that, assuming Einstein was correct, and nothing can go faster than light, then those aliens would not be able to visit our galaxy. Even the closest large galaxy outside the Milky Way - Andromeda - is 2 million light years away.  At 0.2C, a space vessel would take 10 million years to cross between.   That seems to me to be pretty much impossible.


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## jojajihisc (Jul 4, 2010)

skeptical said:


> The Fermi Paradox is a question, not an implication.



That's right, it is a question and I could have included that in the quote I gave as Freitas mentions it. Here is the expanded quote.



> Fermi's question "Where are they?" implicitly construes the absence of extraterrestrials on Earth as positive evidence of their nonexistence elsewhere in the Universe.



However, you may have also misunderstood how the word "implicitly" was used in the quote. It's used as an adjective to modify "construes" the noun. The quote isn't saying the paradox is an implication it is describing what the paradox does. I guess my only point here is that the question is not very sound because the absence of evidence for alien's existence is not itself evidence for their nonexistence. 

I should also say that I agree with your final statement where you said



> Simplest answer is that advanced life forms are sufficiently rare that no such aggressively expansionist species has evolved in our galaxy.


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## mosaix (Jul 4, 2010)

The straight answer is that we don't know - nobody knows - so any explanation put forward is guesswork.

My guesses as follows: there are billions of galaxies out there, each with billions of stars and each star has the potential for planets. With all those planets I guess that the accident of life has probably been repeated somewhere. Intelligent? I don't know.

Have we been / are we being visited? Given that Earth is just one planet amongst all the rest, I find it unlikely that aliens could find us and, even if they've detected our radio / TV transmissions, I don't think there has been enough time to travel here. So my guess is that unidentified flying objects remain just that - unidentified but not alien.

Other things that persuade me against UFO's:

1) Why haven't they contacted us? If they're hiding they're not very good at it. If their 'mothership' is invisible then why aren't their 'scout craft'? 

2) Why are all their craft different shapes and have different characteristics? Maybe there's more than one set of aliens studying us? I think that is even more unlikely.

One thing about the human psyche that shouldn't be forgotten is that when presented with _something that we haven't yet explained  _people will tend to come up with an explanation that fits with a _previously held belief that they would like to be proved to be true. 

_I know this isn't the case with everybody, but in the past 'sightings' have been taken to have religious significance, nowadays they have alien significance. 

I would love us to discover alien life in the universe. I think Mars is the best bet and that it is microbial. I just hope it happens in my lifetime.


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## jojajihisc (Jul 4, 2010)

jojajihisc said:


> It's used as an adjective to modify "construes" the noun.



Or rather it's an adverb modifying the verb. That's what I get for trying to give a grammar lesson.


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## JDP (Jul 5, 2010)

Still waiting for signs of intelligent _terrestrial _life. My money's on the dolphins.

:-D


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## Doctor Crankenstein (Jul 5, 2010)

http://www.sffchronicles.co.uk/forum/members/skeptical.htmlSkeptical, there is one problem I have with your experiment. 

Surely a race that is advanced enough to populate an entire galaxy would be intelligent enough to realise the dangers of overpopulation? Furthermore, who says they have the same sense of curiosity and explanation that humans do? Perhaps they are quite content sitting in their small corner of the galaxy playing Pazaak.


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## JDP (Jul 5, 2010)

The Fermi Paradox relies on the assumption that an alien (super?)intelligence would _allow_ us to see signs of its existence. They might be happier for us to remain in ignorance, á la the Zoo or Planetarium Hypotheses...


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## skeptical (Jul 5, 2010)

To Dr. Crank.

Sure, there may be intelligent species sitting at home and playing philosopher.    However, it seems to be a law of nature that every species has a drive to disperse.  An intelligent species would have individuals willing and keen to explore outside what we consider to be the norm.  Humans certainly have enough individuals willing to put their lives at risk to go somewhere no-one else has ever been.

It seems to me that, while a few species might be happy stay-at-homes, others will be expansionist.   If there have been more than a tiny number of intelligent species in our galaxy, over 6 billion years, it would be strange if some had not explored and colonised widely.  With a maximum of 10 million years to fully populate the entire galaxy, we should have no problem seeing signs of those beings.


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## jojajihisc (Jul 6, 2010)

Of course we could have problems seeing signs of those beings. They'd be more advanced.


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## J Riff (Jul 6, 2010)

Again, we have been civilized for less than the blink of an eye. Aliens may well have stopped off here regularly, for millenia, picking up lifeforms or whatever they wanted. No reason to expand and take over the galaxy, maybe they have a few hundred thousand planets nearer the galactic core where they prefer to hang out. 
 If there was a way to find out for sure, I'd wager on there being rafts, thousands of them... the universe is unbelievably huge and impossibly old, we are blowing smoke to dream we are the only ones with intelligence.


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## Boneman (Jul 6, 2010)

and as Calvin once said to Hobbes (although it could have been the other way around) 


"The surest sign that there is intelligent life out there, is that none of has visited here..."


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## Doctor Crankenstein (Jul 6, 2010)

Haha, I like that


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## [B00M] Headshot. (Jul 9, 2010)

Honestly I personally believe that all Inteligent life that Humans can comprehend has moved on, or are in another remote solar system far, far ,far away and probably face the same dilema of why they are the only intelligent species around and kicking, My reasoning for this is that this galaxy is reasonably old, old enough for life that Humans can comprehend has long ago realised that this galaxy no matter how infinite would be crowded and run out of resources eventually  and left in an exodus, or they would have changed there species beyond our biolgical understanding.


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## [B00M] Headshot. (Jul 9, 2010)

btw Im new here, and also I like that too Crakenstien. (sorry for spelling mistakes; far too lazy to re-read =) ).


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## StormFeather (Jul 9, 2010)

Boneman said:


> and as Calvin once said to Hobbes (although it could have been the other way around)
> 
> 
> "The surest sign that there is intelligent life out there, is that none of has visited here..."


 
Another Calvin and Hobbes fan  - I absolutely love them!


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## Vertigo (Jul 9, 2010)

Let me first say that I would love to find that we are "not alone". And I _think_ I believe there has to be some other life out there somewhere, intelligent or ortherwise. However here are some slightly pessimistic views.

1. Maybe FTL travel is truly physically not possible. This makes exapnsion across the starts difficult and hard to justify for any civilisation, where's the return - several hundred years down the line? Ultimately exploration is never altruistic it is always looking for riches. Maybe then there have been many civilisations that have grown, exhausted their planet's/system's resources and then dwindled. Mote in God's Eye paints an interesting view of how such a civilisation might rise and fall (many times in that case).

2. If we look at life on our planet (OK I know that's a limited view but it's the only one we have hard evidence for) then all the more intelligent animals are territorial and/or predatory. Some degree of intelligence seems to be required to be a predator but not to be prey. This inevitably makes then aggressive towards each other to protect their resources. The result is something like us where, lets face it, if we can survive the next hundred years or so without obliterating ourselves then it's likely to be a small miracle. Given that, it is quite possible there have been millions of alien civilisations but that they have simply never lasted long enough to overlap in time. Each one just a tiny tick in the cosmological clock.

3. Current belief (as I have mentioned on another thread) is that based on the identical nature of DNA in all life on Earth, all life must have descended from one single cell. In other words only once in the "life" of this planet have chemicals come together in such a way as to replicate themselves in an organised and yet mutable (no that's not the right word I mean something that can mutate) fashion that eventually produces life as we know it. This rather lessens the probability of life occurring everywhere else even if there are suitable environments.

Ultimately I guess I'm hopeful but not overly optimistic


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## Dave (Jul 9, 2010)

Vertigo said:


> 3. Current belief (as I have mentioned on another thread) is that based on the identical nature of DNA in all life on Earth, all life must have descended from one single cell.


 There is also the idea of Panspermia ;that the DNA, or the cells containing it, was seeded from elsewhere. Fred Hoyle was a proponent of this idea, but it also formed the basis of the Star Trek TNG episode 'The Chase'.


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## skeptical (Jul 9, 2010)

The problem, IMHO, of panspermia, is that the genetic and fossil evidence suggests that all life began on Earth at one time, about 3 to 4 billion years ago.  Panspermia would imply a rain of life onto Earth, meaning new genetic material injected on a regular basis.   There is no evidence of this.

I agree with vertigo that life outside Earth is probably rare.  I do not think that the lack of ability to travel FTL is necessarily a barrier to interstellar travel, though.

My feeling is that we will begin a stage in space travel, some time in the next several hundred years (a mere eyeblink in time) in which largely self sufficient space cities will be built.   Something like a giant cylinder, rotating for artificial gravity, and with sufficient water ice in its outer layer to protect from radiation.  

Once we have such space cities, travel to another star becomes possible.   Simply strap on a large enough ion drive engine capable of accelerating (and decelerating) to a high fraction of light speed.

If it takes 10 years to accelerate/decelerate to 0.1c, then the time to reach Alpha Centauri is 55 years.  A self sufficient space city could do this.  They will know in advance what to expect since giant space telescopes will view the system first, and automatic probes will have explored also.

Project this idea way into the future, and expansion throughout the galaxy will take a few million years.  Compared to the age of the galaxy, this is still a very short time.


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## Dave (Jul 9, 2010)

skeptical said:


> The problem, IMHO, of panspermia, is that the genetic and fossil evidence suggests that all life began on Earth at one time, about 3 to 4 billion years ago.  Panspermia would imply a rain of life onto Earth, meaning new genetic material injected on a regular basis.   There is no evidence of this.


I disagree. I'm not saying that I believe in it, in fact, I'm sure I don't. However, there is nothing in stopping all the chemicals needed for Life to be present on Earth and cell-like objects forming, when one single DNA wafts down from space and seeds the whole lot to start multiplying. I don't see why tops ups on a regular basis are required, but I'm willing to be educated on that. There are many other problems though, the first is that DNA is not likely to survive long on it's own, especially in space. This whole idea requires some hand (god or alien intelligence) for it too happen. It couldn't happen by accident and chance alone, which is the idea I favour.


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## skeptical (Jul 10, 2010)

Dave

It depends on your definition of panspermia.  While the theory really only talks of the 'seeds of life' coming from off Earth, most scientists would see the theory as being actual life forms arriving from off Earth.  

This is not impossible, and I suspect that Earth bacteria may already have reached Mars.  Probably just to die there, but who knows.  The asteroid impact that killed the dinosaurs would have the energy to throw Earth rock into space, and clear of Earth's gravity, and some would eventually intersect Mars orbit.  Experiments have shown that some bacterial spores can survive prolonged periods in simulated outer space conditions.

Since meteorites of Mars origin get picked up occasionally here on Earth, the reverse is quite possible.

However, if it can happen once, it can happen many times, and there is no evidence of different forms of life arriving on Earth any time after the origin of life, perhaps 3 billion years ago.


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## J-WO (Jul 10, 2010)

skeptical said:


> If it takes 10 years to accelerate/decelerate to 0.1c, then the time to reach Alpha Centauri is 55 years.  A self sufficient space city could do this.  They will know in advance what to expect since giant space telescopes will view the system first, and automatic probes will have explored also.



The idea becomes even more attractive when one considers our recent advances in genetics and the consequent possibility of extended lifespans. What's 55 years to a millennial 20 year old?

Its weird how, just 25 years back, most SF saw FTL as a likely possibility but a cure for death as a total no-no. Nowadays its the other way around.


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## Vertigo (Jul 10, 2010)

J-WO said:


> The idea becomes even more attractive when one considers our recent advances in genetics and the consequent possibility of extended lifespans.


 
That's a topic I want to have a good old natter about sometime though maybe not just now - got enough topics I'm interested in to keep me too busy already 



Dave said:


> There is also the idea of Panspermia ;that the DNA, or the cells containing it, was seeded from elsewhere. Fred Hoyle was a proponent of this idea, but it also formed the basis of the Star Trek TNG episode 'The Chase'.


 
I agree and I too am personally skeptical of this idea; as skeptical says if it happened once it would seem likely to happen more than once. Interestingly it still brings us to the point that that "introduced" life must have come from a single source as well 



skeptical said:


> I agree with vertigo that life outside Earth is probably rare. I do not think that the lack of ability to travel FTL is necessarily a barrier to interstellar travel, though.
> 
> My feeling is that we will begin a stage in space travel, some time in the next several hundred years (a mere eyeblink in time) in which largely self sufficient space cities will be built. Something like a giant cylinder, rotating for artificial gravity, and with sufficient water ice in its outer layer to protect from radiation.
> 
> ...


 
I tend to agree with this (as I said I was trying to play Devil's Advocate in my earlier post) however I still make the point that ventures of that nature have historically only been attempted with the promise of high returns. I guess if you picture an overcrowded solar system then the return would simply be the escape. However the resources required to build such a thing would be enormous and someone would have to stump up the cash/energy. Maybe by then we would have developed energy sources that make energy incredibly cheap in which case it might be possible.

Incidentally I should clarify my second point in my earlier post - I am effectively suggesting that maybe agression to one's own species is a inevitable partner to intelligence. This is obviously very debatable but on the other hand lack of such aggression would imply living in complete harmony with your environment without overpopulating it and so creating resource pressures (which after all is pretty much what all other creatures than us do on this planet ). However such a creature, living in such harmony would probably have no motivation to expand beyond their own environment/planet.


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## jojajihisc (Jul 10, 2010)

J-WO said:


> Its weird how, just 25 years back, most SF saw FTL as a likely possibility but a cure for death as a total no-no. Nowadays its the other way around.



Interesting point and I've noticed it too. 25 years ago the idea of digitizing a consciousness was in its infancy and now it seems imminent. Fingers crossed.


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## Vertigo (Jul 10, 2010)

Another thought on this. As you move in toward the centre of the galaxy (any galaxy that is) the concentrations of stars increases quite significantly. Now I may be wrong but I believe it is generally considered that any life form with which we are familiar simply could not take the concentrations of radiation that would be around in those parts. Now of course maybe other forms of life could take those radiations and if so would probably even need them. In which case for them the outer regions of the universe would probably be fairly unattractive hence we don't get to meet them. On the other hand I'm not so sure any carbon based life form could take those levels of radiation in which case the statistics for finding other life suddenly takes a bit of a dive.

Yes I know we have one or two critters around that can take fairly large doses of radiation but none of them are what you might call higher orders of life.


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## J-WO (Jul 11, 2010)

skeptical said:


> The problem, IMHO, of panspermia, is that the genetic and fossil evidence suggests that all life began on Earth at one time, about 3 to 4 billion years ago.  Panspermia would imply a rain of life onto Earth, meaning new genetic material injected on a regular basis.   There is no evidence of this.



I'm not much of a buff on these things, but it strikes me that, if non-DNA life did/does fall upon the Earth it could never garner a foothold--native DNA life would simply outpace and expunge it. The chances of scientists discovering any in time (and bare in mind, these 'invasions' could be so rare as never have happened since before the advent of modern science) would next to impossible.


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## Vertigo (Jul 11, 2010)

It's a good point J-WO and is in fact the argument against my observation that there appears to have only ever been a single instance of the creation of cell that can reproduce. It is possible there have been many such occasions but they have never managed to out-compete the already existing one.

One or two other thoughts about the probabilities out there with reference to suitable planets for the development of intelligent life. I'm no expert on these and so please correct me if I'm wrong on any.

1. Need a protector planet like Jupiter to avoid being blown away by space debris

2. Need a suitable moon to stabilize our orbit from wobbling too much. Well know gyroscopic effect which would potentially create massive seasonal swings and a hopelessly chaotic climate. I believe simulations have shown that without the moon Earth would have spent significant periods of time with our axis of spin pointing straight at the sun.

3. Need a magnetoshere to protect our atmosphere from solar wind. I believe that means we need a molten iron (or at least) metallic core. Isn't that why Mars has such a thin atmosphere now?

4. Need plate tectonics. As I understand it this is an essential component of the recycling of our atmosphere.

5. Need to avoid the Venus style runaway greenhouse effect. Maybe that's cos they have no life to soak up the excess CO2.

If in particular point 3 is correct then the window of opportunity narrows significantly - just how long does a planet retain its molten core. I know that depends on a lot of factors like size etc. but I'm sure it is a lot shorter than the "life" of the planet and its star system.


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## Dave (Jul 11, 2010)

4. and possibly 3. may also be a result of 2.


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## Vertigo (Jul 12, 2010)

I will take your work on that Dave, I'm certainly no expert in the matter 

My main point is to highlight how finely balanced our precious evnironment is and therefore how rare similar environments are likely to be.

Another thought on that is that we all know that there is a "sweet" range of orbit distances for a planet to be ideal for life. But bear in mind that during the time there has been life on Earth there has been something like a 20% increase in output from the sun but that life itself has regulated the temperature of the planet by modifying the atmosphere and held it more or less steady. I believe if things were just getting started now it would be far less likely that life would get started.

Oh and yes I know other things can generate a similar benign environment such as the gravitic influence of Jupiter on some (or is it just one?) of it's moons heating them and possibly allowing for the possibility of life well outside that "sweet band".


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