Aliens- do they exist??

[Paul67]

Great thread.

Regarding travelling to distant star systems and by today's knowledge it seems many years away, perhaps hundreds of years if at all. We must consider AI in all of this. It is estimated that AI will pass the "Turing test" for intellect by the year 2030, which is a point at which AI will be on a par or surpass Human intellect.

From this point onward's AI will be able to rebuild itself with ever increasing intelligence beyond what we as humans are capable of doing. If this is directed towards spaceflight then  it could be possible we are far closer than what we think towards heading for the stars. We could have a technological revolution the likes of which comes straight out of a  Peter Hamilton novel. 

[philthy]

On 2/4/2018 at 22:11, Stub Mandrel said:

I'm with Asimov on this - is practically impossible for a civilisation to leave its home system

If you believe in the scientific theories that hold sway at present.

A caveman living on an island would have thought the same

[saac]

14 hours ago, philthy said:

If you believe in the scientific theories that hold sway at present.

A caveman living on an island would have thought the same

But the caveman would have been wrong as the physics which prevailed did not bind him to his island.  Weather we will be ultimately bound by the physics remains to be seen. I think we will find that the distances and energies involved will keep us bound to our solar system.

 

Jim 

[Ben the Ignorant]

No one has a time machine to see what future inventions will be.

[Stub Mandrel]

1 hour ago, Ben the Ignorant said:

No one has a time machine to see what future inventions will be.

Can you prove that?

[Gina]

Just because nobody has been seen from the future doesn't necessarily mean they haven't been here.  They might have adopted "The Prime Objective" of Star Trek.  And don't dismiss the theories of Star Trek just because it's science fiction - lots of things that were science fiction a few years ago have become science fact.

OR maybe they have been seen - as UFOs

[Pig]

The Fermi paradox is simply a very good / enjoyable topic of conversation ? and is a typical example of what makes us unique, but unique does not mean alone.

[philthy]

23 hours ago, saac said:

But the caveman would have been wrong as the physics which prevailed did not bind him to his island.  Weather we will be ultimately bound by the physics remains to be seen. I think we will find that the distances and energies involved will keep us bound to our solar system.

 

Jim 

His physics, that prevailed at that time, bound him to the island, it was too far to swim to the nearest island and there were sharks,until somebody came up with the theory that a dugout canoe would allow them to cross.

[saac]

12 hours ago, philthy said:

His physics, that prevailed at that time, bound him to the island, it was too far to swim to the nearest island and there were sharks,until somebody came up with the theory that a dugout canoe would allow them to cross.

 Agreed - what I was hinting at was that the physics was "solvable" , travel from the island was possible - the caveman just needed time.  Whether physics will ultimately constrain us to travel our solar system and no more remains to be seen. I think we will be forever stuck here on our island;with or without sharks, I don't think the physics is solvable  

Jim 

[philthy]

8 hours ago, saac said:

 Agreed - what I was hinting at was that the physics was "solvable" , travel from the island was possible - the caveman just needed time.  Whether physics will ultimately constrain us to travel our solar system and no more remains to be seen. I think we will be forever stuck here on our island;with or without sharks, I don't think the physics is solvable  

Jim 

That is your opinion, fair enough.

I think that we don't know enough about the physics of the universe to make that judgement.

[Stub Mandrel]

You cannae change the laws of physics!

Laws of Physics!

Laws of Physics!

You cannae change the laws of physics!

Laws of Physics, Jim!

 

[JohnSadlerAstro]

Hi,

I am a sceptic of people who follow the Drake Equation, etc. To me, the fact that there are *as yet* no signs of life on Mars or elsewhere in our solar system (although there are still lots of places to look) would suggest to me that life is more complex than many believe. 

Something that made me think about this first was when I read an old Sci-fi book called "Kings of Space" by W. E. Johns (of Biggles fame). Because it was written before space travel of any kind, he made some basic assumptions about the occurrence of life. Essentially, in the book, there is some form of life on almost every planet in the solar system and galaxy. This seemed a perfectly plausible assumption to make at the time (1940s-50s); but the apparent "failure" of life to exist anywhere outside of our planet suggests to me that life sorely limited in the forms it can have.

Following this argument through: if extra-terrestrial life were found, I would expect it to have almost identical form to that on Earth.

John

[saac]

4 hours ago, philthy said:

That is your opinion, fair enough.

I think that we don't know enough about the physics of the universe to make that judgement.

philthy, it's all about energy and the vast distances v human life span.  Dragging ourselves from the confines of Earth's gravity-well was just about possible given the energy density of the propellants we had available.  It is difficult to see what future source could provide the energy density required for interstellar travel; certainly not chemical that is for sure.  I think the physics is pretty well understood, what may of course change is our technology so I guess we can never say never, I won't be holding out for a concession ticket any time soon though.  

 

Jim

[Whirlwind]

19 hours ago, saac said:

philthy, it's all about energy and the vast distances v human life span.  Dragging ourselves from the confines of Earth's gravity-well was just about possible given the energy density of the propellants we had available.  It is difficult to see what future source could provide the energy density required for interstellar travel; certainly not chemical that is for sure.  I think the physics is pretty well understood, what may of course change is our technology so I guess we can never say never, I won't be holding out for a concession ticket any time soon though.  

 

Jim

Travelling interstellar is easy (relatively) once you get up there compared to getting off the earth.  Solar sails, ion thrusters etc are all viable and reachable technologies.  There is even some thoughts on using vacuum energy.  A little bit of thrust over a long time can build up to vast speeds.  Getting off the earth requires lots of thrust over a short time frame. 

As you've pointed out though the limiting factor is the human lifespan.  Either we require vast colony ships to allows generations to develop or we can look at engineering ourselves so we live longer.  This is probably more likely in some ways.  There is no particular reason why we can't bio-engineer ourselves to live much longer than we do (the brain being probably the only part we don't fully understand yet enough to make something that we can patch it when it goes wrong).  Plenty of flora and fauna live much longer than we do, some can hibernate in below freezing conditions, so nature has already shown it can be done.

[Stub Mandrel]

What people always forget is that GETTING to another system is challenging.

How do you get back?

Even if you could colonise another world (let's assume it has breathable air, edible food, plenty of resources and is safe) a spaceship load of colonists might take a few centuries to make an economy capable of building a ship for the return journey, even without wars and a single-minded determination to get back.

Communications with earth would be haphazard at best relying on both home and away to bother keeping in touch despite massive time delays.

More likely a new society would develop and the home planet could sink into a 'Von Daniken' myth.

Hmm, muses on Helliconia and Heorot and wonders if he shoudl write a novel...

[Paul67]

10 hours ago, Stub Mandrel said:

What people always forget is that GETTING to another system is challenging.

How do you get back?

Even if you could colonise another world (let's assume it has breathable air, edible food, plenty of resources and is safe) a spaceship load of colonists might take a few centuries to make an economy capable of building a ship for the return journey, even without wars and a single-minded determination to get back.

Communications with earth would be haphazard at best relying on both home and away to bother keeping in touch despite massive time delays.

More likely a new society would develop and the home planet could sink into a 'Von Daniken' myth.

Hmm, muses on Helliconia and Heorot and wonders if he shoudl write a novel...

For all anyone knows, we may well be that stranded colony. I think it was a Carl Sagan book I read where he said, if you were to travel at close to the speed of light the people in that ship could go around this galaxy and it would appear to take about 50 years for the occupants, meanwhile when they returned Earth would have been consumed by our own giant sun and all life long gone.

[saac]

14 hours ago, Whirlwind said:

  Plenty of flora and fauna live much longer than we do, some can hibernate in below freezing conditions, so nature has already shown it can be done.

Although the most complex thing in the known universe, the human brain, may present nature with one or two more challenges at deep freeze than does a simple spore, unicellular organism or even the (fiendishly complex by comparison)  tardigrade. Notwithstanding some recent articles (see below) which may suggest otherwise, any notion of bio-engineering or downloading the human brain remains even yet a flight of fancy beloved of science fiction. The faith placed by some in such technology certainly appears misplaced. I can't help but think the gulf between the projections of science fiction and reality with respect to life extension mirrors the physical distances and challenges of interstellar travel.

http://www.bbc.co.uk/news/technology-43394758

Jim

[Whirlwind]

Not just single cellular animals  Mammals are known to hibernate at extremely low temperatures.  The artic ground squirrel for example body temperature drops below zero when it hibernates with the brain just above this temperature.  How it manages to repair the neurons after this is an active area of research that might help brain diseases like Alzheimer's.  In general the brain of this squirrel uses similar biological technology to ours. Understanding this provides the opportunity to develop this for humans. 

Brains are in essence complex computers and there are likely areas that are constrained because of the way evolution works and that once in a bottleneck it is difficult to get out of (our eyes are good example, we have a blind spot because of the way eyes evolved over time). The difference is that we can design out these flaws making things more efficient; once we understand the processes there is no reason why we can't replicate them. 

In comparison all tests seem to indicate that the speed of light is a limiting factor based on physical laws.  Bioengineering is not constrained in this same way and is feasible within physical laws.  Our limitation to exploring the local galactic neighbourhood is our limited lifespan rather than the how quickly we can get there.

[Macavity]

I have a feeling that it may just be possible to get a closer look
at the potential  habitats of potential  aliens??? 

https://breakthroughinitiatives.org/

With a dearth of other ideas re. interstellar travel, this seemed
to have some (albeit open to debate!) genuine possibilities...
Plus Stephen Hawking (RIP) reminded me of the general idea.

My personal policy re. interstellar Aliens: "Don't tell 'em, Pike".

[ollypenrice]

On 3/10/2018 at 22:01, philthy said:

 

A caveman living on an island would have thought the same

But it seems that they didn't. The technologically 'primitive' Polynesians learned to navigate between remote islands using methods we are only recently beginning to study and the Australian aboriginals are not indigenous to Australia. They sailed there. All humans are 'out of Africa.' We have always traveled.

It seems to me that the problem with Drake and Fermi is that they make a massive and unjustifiable assumption about intelligence. They assume it must resemble our intelligence and so lead those who possess it to do as we do - make spacecraft and systems of mass communication etc. But their intelligence might lead in other directions. Science should not fall into the anthropomorphic trap. Other systems of thought have made that mistake already.

I have a similar problem with 'Artificial Intelligence.' Its proponents have happily purloined the term 'intelligence' just as they have purloined the term 'memory' and many other terms to describe the capabilities of their machines. This might be very misleading. I see no evidence of artificial intelligence but I see plenty of evidence for something which needs a more precise description. Does my copy of Hamlet 'remember' the text? To be careless with words is to be careless with thought. Beware!

Olly

[Sunshine]

I always say to people who ask me that quintessential astronomy question “do you think aliens exist” I first try to give them an idea of how incredibly vast and old our universe is.  That must be stated before anyone can allow themselves a fair shot at having an opinion.

Afterwards I always bring up Hollywood aliens, aside from being fun to look at and selling millions of tickets at the box office they certainly created an image of alien life people always defer to whenever the word Alien pops up. The typical big headed skinny pale almond eyed alien in a saucer is what people always picture an alien would look like.

Once they have a grasp of the size of our universe more or less, because it’s hard to comprehend even for an astronomer, I break down the word “Extra Terrestrial”  and what it really means because as soon as you mention those words, that skinny alien comes to mind again and always invokes a chuckle.

Once whomever is asking has a basic understanding of those facts then I like to explain how a single microbe wiggling in the oceans of Europa, a hundred kilometers under the ice, would be “Extra terrestrial” life!. Yes!! I’d doesn’t have to be a pale skinny alien! a single celled organism twitching around in a methane puddle on Titan would be Extra terrestrial life!!. Or even a fungus of some sort which is one of the most simplest forms of plant life!.

People almost always revert from chuckles and eye rolling, to a much more serious facial expression, once they forget the Hollywood Alien, almost always, they ponder and I can see their gears turning upstairs lol followed by  “oh yeah true”.

I love every time people ask that question, because it always starts with some chuckling, and ends with them truly wondering, there is no short way to answer it. If given an idea of how many stars, galaxies, and estimated planets there are, then it really opens peoples perspective and they can begin to form an opinion, one which is grounded in fact not fiction.

That is by far my fav question people ask, it gives the opportunity to share with them the vastness of our universe.

 

 

[Ben the Ignorant]

If people chuckle about aliens they should say what facts they know that make it funny.

[Moonshane]

The only real answer that matters at the current time is "dunno".

In terms of probability, if life happened once (it clearly did), then it could never happen again, happen one more time or be ubiquitous. Who knows which and perhaps we'll never know.

My guess is that life will be everywhere in one shape or form. I suspect it will even be common within our solar system once/if we get there in person. Intelligent life only evolves where there is evolutionary pressure for it to do so. In the event that there is then I'd expect intelligent life to be reasonably common too. That said, communicating or travelling over such vast distances (based on current scientific knowledge) is so challenging that we may have destroyed ourselves before we make 'contact' (even if we recognise it as such). 

[Stub Mandrel]

Given that crows and other undeniably intelligent birds are effectively dinosaurs, the potential for dinosaurs to have evolved to a human-like level of consciousness in their 160 million year dominance of the planet must have been there. Yet presumably the environmental challenges they met did not lead to its evolution.

I also suspect the curiously balanced earth-moon system had implications for the evolution of complex life.

My feeling is that life may well be relatively common, if not ubiquitous. Complex multicellular life rather less abundant and technological civilisations rare.

[Moonshane]

45 minutes ago, Stub Mandrel said:

Given that crows and other undeniably intelligent birds are effectively dinosaurs, the potential for dinosaurs to have evolved to a human-like level of consciousness in their 160 million year dominance of the planet must have been there. Yet presumably the environmental challenges they met did not lead to its evolution.

 

Evolution is nothing to do with a path toward intelligence, it's purely a mechanism favouring the organism most suited to the prevailing environmental conditions (i.e. the 'fittest'). It requires 'pressure'. e.g. in a world where the most suited organism to the environment is a single-celled bacterium, then that's what will remain ad infinitum until environmental pressure or mutation creates a 'fitter' organism which then changes the balance.