[DonQuichotte (OP)]

Are We Alone in The Universe ?

Are we, dear folks ?
Since there is more than billions and billions of galaxies out there , and much more maybe , it's pretty possible and logical to assume that some kind of life might have emerged on some planet out there, we do not know of  .

Maybe some advanced aliens out there "manufactured " us , human beigns , also , who knows ?

Our human reality might be just a kind of elaborate matrix or hologram , who knows .

Do tell me about just that , please , i am serious , thanks , appreciate indeed .

Cheers .


The Secret Evidence We Are Not Alone :


http://topdocumentaryfilms.com/secret-evidence-we-are-not-alone/

[alancalverd]

Probably not.

As for our being an artefact, why?

[DonQuichotte (OP)]

Probably not.

As for our being an artefact, why?

How can you be so sure about that then ?
Have you explored all the universe already , via some time travel machine maybe ?

[DonQuichotte (OP)]

The funny thing is that i asked a friend of mine the same above mentioned question of this thread , and guess what he replied :
"Are we alone on earth?, Are we the one and only truely intelligent beings on earth  ? "
He added : i am not referring to any of the other known  living organisms on earth ...

[Ophiolite]

It is dangerous to extrapolate from a sample size of one.

Either way, the two alternatives, alone or not alone, are amazing to contemplate.

[CliffordK]

It is dangerous to extrapolate from a sample size of one.

Absolutely.
One could think of Earth as "average", but among all the earth-like planets that exist, somewhere one has to be first, and one has to be last.

It is believed that shortly after Earth was first capable of supporting life, then life in fact developed.  This might indicate that any planet like Earth (which we would have to assume there are others) would also develop life.  Or, it might indicate that everything came together at the right time.  Even if abiogenesis was inevitable, the jump from prokaryotes to eukaryotes was apparently slow, and may not always occur everywhere.

We can be amazed by the harmony of nature.  But, life could well have extinguished itself too. 

While Earth may have the only sentient multi-cellular beings in our solar system, perhaps more analysis of Mars, Europa, and Titan, as well as the many asteroids will reveal evidence of either current, or previous life elsewhere in our solar system.  Then its characteristics will help us understand life in general.

[alancalverd]

It is dangerous to extrapolate from a sample size of one.

Which is why it is worth applying Bayesian statisics and asking what if anything is remarkable about your tiny sample. This leads quite nicely to the Drake equation which suggests (a) there is a nonzero probability that something we might call life either exists, may have existed, or will exist somewhere else in the universe and (b) we are most unlikely to find it. Such cautious statistical analysis is a long way from the Goldilocks or anthropocentric extrapolation, even if conclusion (b) is indistinguishable from the Goldilocks result! 

[AndroidNeox]

Personally, I find the idea that Earth is the only home of life to be unlikely. Your suggestion that we could exist as nothing but a Matrix-like simulation is untestable (unless you could find a bug in the system). Really, we know information exists but we can't prove anything else (see Wheeler's "It from bit").

[CliffordK]

Your suggestion that we could exist as nothing but a Matrix-like simulation is untestable (unless you could find a bug in the system).

It would take an enormous amount of computing power to simulate 7 billion people, and about 20 billion chickens, and all the other creatures. 

Of course, if one looks at life through the eyes of a single person, then one only really ever sees at most a thousand or so people at at time.

Then one would have to ask to what end we are in this incalculable simulation.  Perhaps like an ant farm, but still the effort to manage it would be extraordinary. 

I think the same would go for having some magical figure controlling every aspect of our lives, and listening to billions of prayers a day.

As far as we can tell, the other planets in our solar system do just fine without "life".  And, even Earth could exist quite fine without humanity.

We may well be just an accidental coalition of amines and hydrocarbons that somehow started catalyzing their own regeneration.

[David Cooper]

I expect we'll have evidence of life on another planet in another star system within the next couple of decades, and it wouldn't surprise me at all if it happened before 2020. Finding intelligent life on our own level will be a lot less likely, but again I think it'll be out there somewhere and we may get a signal from it some day. Perhaps we'll meet up with some of them when our galaxy merges with M31 (though meeting directly could be lethal for all involved due to unfamiliar bacteria and their alien equivalents).

[CliffordK]

If we find a planet in the Goldilocks zone, with an oxygen rich atmosphere, we could start beaming continuous radio signals in that direction.  Perhaps alternately broadcasting in AM, FM, and binary pulses, all either in multi-frequency, or variable frequencies.

If the other planet either knew of our existence, or happened to be tuned in this direction, they might pick up the signal. 

Still, if the planet was 100 light years away, it would take about 2 centuries to exchange a simple "Hello".

Could we design a probe capable of enduring for a million year trip, or so, just to check it out?

Of the 300 billion stars in the Milky Way, we might not have to wait for Andromeda to possibly stir the pot after our sun likely expands to the red giant phase.

[Ophiolite]

It is dangerous to extrapolate from a sample size of one.

Which is why it is worth applying Bayesian statisics and asking what if anything is remarkable about your tiny sample.

When we do this we discover we lack the knowledge, currently, to answer that question for several key issues.

This leads quite nicely to the Drake equation which suggests (a) there is a nonzero probability that something we might call life either exists, may have existed, or will exist somewhere else in the universe

The Drake equation is generally misunderstood and misapplied. Frank Drake introduced the equation as an agenda for a meeting on extra-terrestrial intelligence held at the Green Bank observatory in the early 1960s. He did not intend it as a serious means of estimating the number of ET civilisations. Later he seems to have forgotten his own intentions and readily made such estimates with it.

The equation only generates a non-zero probability if one arbitrarily introduces non-zero terms in all of the functions within the equation. At present we lack the data to this with full confidence.

(b) we are most unlikely to find it.

This is not the case if you take the more ebullient numbers proposed by some researchers. Nor is it the case if you accept the improvements to be expected from technological advances in our ability to detect life forms elsewhere. So, this is not a conclusion we can form from proper application of Drake.

Such cautious statistical analysis is a long way from the Goldilocks or anthropocentric extrapolation, even if conclusion (b) is indistinguishable from the Goldilocks result! 

Since the use of the Drake equation implicitly involves identification of Goldilocks zones I fail to see how you can make this assertion.

[alancalverd]

My misappropriation of Goldilocks as being "just right" - i.e. anthropocentric - as distinct from "good enough" to support a selfreplicating organism.

I would be extremely surprised if there was nowhere else in the universe with some kind of green slime or uber-Klingon in residence. I would be (extremely)² surprised if it ever made contact with homo sapiens. And given what hom sap did to the dodo, and even to tribes of its own species, the prospects for a joyous outcome to such a meeting are not hopeful anyway.   

[Ophiolite]

My point is that what would or would not surprise you (or any of us) has little foundation, since our knowledge is currently inadequate in too many areas. i.e, back to my original point about extrapolating from a sample size of one.

[alancalverd]

Hold on! The sample size is at least a dozen planetary objects (i.e. including large moons) , and thousands of smaller chunks of rock, in the solar system, of which only one is known to support life and only two others (Mars and Europa) might have or have had the capability of doing so - assuming that life involves selfreplicating systems that transpire water. 

Now given the very small range of orbital radii around any given star, within which water will remain liquid, and the minimum size of planet needed to retain water in its atmosphere, it's unlikely that any star will have more than one Earthlike planet in the right orbit. So we are beginning to put some real numbers into Drake. We need a star of similar age and composition to the sun to provide a reasonably stable energy input without too much ionising radiation, and since that pretty much defines the mass range of the candidate star, we can begin counting candidates.

It is sensible to double the actual number of candidate stars on the grounds that we know of at least one moon  that probably contains liquid water on account of its internal heat and suitable size.

In other words we really have enough knowledge of the conditions required to sustain anything we might call life, and of the distribution of star types  at least within a few galaxies (which we may as well assume to be typical) to set an upper limit on the probability of life existing elsewhere. Hence my opinion that it is nonzero but exceedingly unlikely to be found. 

[SimpleEngineer]

I think basing any of the guesswork around the possibility of life outside the constraints of a planet like, or similar to the earth on the basis of how life developed here is a little arrogant on our part. We dont understand life, we dont even have an idea WHY things that we call life happened to form..

Yes, we can go into a primordial soup state and say that somehow long chain hydrocarbons began to separate the outside from the inside (definately the first step towards life in my opinion).. We do understand HOW the hydrocarbons did this, (hydrophilic and hydrophobic tendancies) we can even do some damn good guess work on where the hydrocarbons came from.. but between the step of inside/outside separation where did the drive come from for the little protocell structures to actually take in energy, and reproduce.. we can say that it may have been happenstance, that these protocells had excess energy and needed something to do with it, so they reproduced without really knowing what it was doing..  at some point a driving force appears that makes the protocells WANT to reproduce, WANT to produce energy, WANT to get better at doing things.. (unless the belief is of accidental evolution) where the transition went from protocells getting energy from the sun to protocells 'eating' each other isa probably better understood, but the driving force behind it is still not clear..

Some say that the mitochondria (not mitichloriants for Jedi's) is actually a lifeform in itself and provides the driving force for life, but how did these structures develop? I find it hard to rule out both that, some intervention at any point in that cycle.. or that this cycle is not driven by natural forces.

There are lots of IF's in the discussion, but I dont believe we have the full understanding of 'life' or the driving forces to say that this could not happen in different circumstances, whether this could happen in a gaseous state, or under supercritical conditions, (evidence is starting to show it very may well be able to with extremophiles).

It wouldnt take too much imagination to see that maybe there are beings as big as planets out there, compensating for much lower pressures, having just formed a segregated boundary and developed processes within that can be described as lifelike.

For me the chances of there not being anything else (at all) is incredibly remote, however, is there a chance of intelligent beings out there?, is another thing entirely. And I am sure if they knew we were here, they would be as excited as we would be to find others out there.

[Ophiolite]

Hold on! The sample size is at least a dozen planetary objects (i.e. including large moons) , and thousands of smaller chunks of rock, in the solar system, of which only one is known to support life and only two others (Mars and Europa) might have or have had the capability of doing so - assuming that life involves selfreplicating systems that transpire water. 

The sample referred to is the the one known existence of life. We do not have adequate information on the other potential sites in the solar system. It is entirely possible Venus was capable of supporting life initially before runaway greenhouse conditions kicked in. Titan has not been ruled out. Enceladus is now considered in a similar category to Europa. Bottom line: we simply do not know.

Now given the very small range of orbital radii around any given star, within which water will remain liquid, and the minimum size of planet needed to retain water in its atmosphere, it's unlikely that any star will have more than one Earthlike planet in the right orbit.

Simulations suggest one is likely and two are entirely possible, even taking into account a shifting HZ as the star evolves.

So we are beginning to put some real numbers into Drake. We need a star of similar age and composition to the sun to provide a reasonably stable energy input without too much ionising radiation, and since that pretty much defines the mass range of the candidate star, we can begin counting candidates.

There are plausible arguments in favour of much cooler stars than the sun - not so many for anything hotter than a G-type. But there are also major issues about proximity to the galactic centre and time spent outside of the spiral arms. The picture is much more complicated than the one you present.

That said, we are, as you suggest, able to apply meaningful numbers to potential habitable planets. The same simply cannot be said of the other terms in the equation. Opinions, based upon careful consideration of the available facts, not upon assumptions, lead to a range of assessments as to the probability of abiogenesis. On the one hand we have the optimistic view of Christian de Duve, Nobel laureate, whose book The Cosmic Imperative explains why he sees life as inevitable and abundant. On the other hand is the pessimism of Jacques Monod, another Nobel laureate, who believed life was a freak accident, unique to Earth.

The only thing I can say with confidence is that we are ignorant.

 

[alancalverd]

The suggestion that a freak accident could only occur in one place in the universe is somewhat baffling. There is always a cause for every effect, and we only ascribe "freak" to effects if the cause was a priori improbable or unconsidered. But once we have sorted out the cause of an accident it always becomes clear that the consequences were inevitable from the starting conditions. So given a very large universe and a very long time, we only need to see the starting conditions (or something similar) once more to answer the question. 

It might be argued that abiogenesis resulted from a primal cause via an inherently chaotic pathway, but however random a system, the probability of it being is the same state twice is nonzero. 

So my opinion is inevitable (it's happened at least once, so p=1 somewhere) but not very abundant.

[DonQuichotte (OP)]

Are we alone ...on earth ?
This is a serious question though , no kidding .

[alancalverd]

No. I have a girlfriend, a dog, and numerous parasites, commensals, symbionts, gut flora, and all the other biological stuff that makes life possible and interesting. What more could anyone want or imagine? An invisible Klingon?