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

[arildno]

Aah yes. Yet again a useless and pointless comment.

And the Drake equation remains worthless all the same.

 

[DaveC426913]

Oh yes, as for hedging bets, isn't that the only logical position to assume? Why should we assume what is or is not possible given our limited knowledge of the facts and an incomplete physics?

But he wasn't hedging like this: "I believe that there are likely alien craft, but I'm open to the possibility that there are not."

He was hedging like this: "I believe that there are definitely alien craft, but I'm going to say they only explain a few of the juiciest sightings."

The latter is making a commitment but then trying to backpedal.

It's sort of the difference between:
"In a boxing match, I will bet on the winner AND make a side bet on the loser." (perfectly acceptable)
and
"I will bet on the winner but afterward I may claim I wasn't serious." (if you're going to bet you'd better have the courage of your convictions).


Anyway, this is a totally academic sidebar discussion...

 

[PIT2]

The latter is making a commitment but then trying to backpedal.

Actually, i was admitting that I am in no way sure or convinced that alien visitations occur.

"I will bet on the winner but afterward I may claim I wasn't serious." (if you're going to bet you'd better have the courage of your convictions).

After what? After we have colonised the entire universe and completely dug up and inspected the soil on all planets and proven that no aliens visited us? Oh and it would have to happen in my lifetime or i wouldn't be able to feel the shame of being proven wrong and thus claim that i wasnt serious...
It makes no sense.

 

[setAI]

I voted yes- but I do not believe in little grey men-

we have probably been 'visited' by every form of intelligence in every universe that has achieved universal quantum computing or classical hypercomputing: through physically equivalent quantum simulations of our universe- the foamy quantum spaces between the atoms of our world and bodies likey contains a vast zoo of sub-femtotechnological computation interfaces emerging out of the quantum multiverse from more forms of intelligence than their are atoms in our observable universe- but of course there is no way to find any evidence yet- [soon]

which means that there aren't any silver saucers or skinny grey aliens running around- we are more likely just one of an infintude of reality shows- [but who/what- if anyone- is watching? and is our 'show' interactive?]- it is naive to think that technology would remain stuck in the industiral paradigm- industry is merely a brief ignition where intelligence evolves toward total integration/access with all information- SETI needs to stop scanning the heavens and start scanning the Planck scale

 

[PIT2]

we have probably been 'visited' by every form of intelligence in every universe that has achieved universal quantum computing or classical hypercomputing

Does that mean we are a simulation?

 

[setAI]

Does that mean we are a simulation?

the Simulation argument is very compelling- but I think ultimately moot becasue of the superposition principle: every possible process that could generate our world exists in superposition and our world is the sum-over-histories- some of those histories started as a simulation and some as a natural physical process- and some arise randomly- but it is the total of these in superposition that allowed our world to exist as it does- thanks to unitary quantum mechanics

which also means that every possible intelligence that has acheived/obtained the necissary computing or physical resources to simulate a world like ours is capible of interfacing with it at a fundamental level- perhaps some can only watch and others can interact- who knows? the point of this idea though is that industrial age flying vehicles with intelligent animals on them soaring through vast interstellar space is unrealistic- real aliens would be much more intimate and subtle

 

[PIT2]

the point of this idea though is that industrial age flying vehicles with intelligent animals on them soaring through vast interstellar space is unrealistic- real aliens would be much more intimate and subtle

What kind of travel would it be, in what kind of devices?

 

[vanesch]

In as much as the universe is much bigger than just the simple "visible universe" in physically different ways (bubbles in inflation, MWI style situations or other), and in as much that the anthropic principle plays a role (which is debatable, but is nevertheless an argument), I think the probability of intelligent life might be way way way lower than we would simply (Drake-style) estimate it on some naive considerations. After all, the simple fact that we are here, in as much as this is biased by the anthropic principle, might only mean that there could be some other intelligent lifeforms in *the entire universe*, but given that that is way way bigger than the visible universe, we might still be very alone in our visible universe!

 

[DaveC426913]

Btw i really don't care if I am called a believer. If i did, i wouldn't openly admit that i think alien visitations are more likely to have occurred than not, would i?

That was not meant as a sleight. I'm just trying to determine if you do think we have indeed been visited. i.e. if you had to bet your life on it, on which side would you bet?

 

[DaveC426913]

And the Drake equation remains worthless all the same.

Are you hoping someone will beg you to share your wisdom? Or do you just have a whim to poop on an otherwise perfectly good discussion?

 

[Ivan Seeking]

In as much as the universe is much bigger than just the simple "visible universe" in physically different ways (bubbles in inflation, MWI style situations or other), and in as much that the anthropic principle plays a role (which is debatable, but is nevertheless an argument), I think the probability of intelligent life might be way way way lower than we would simply (Drake-style) estimate it on some naive considerations. After all, the simple fact that we are here, in as much as this is biased by the anthropic principle, might only mean that there could be some other intelligent lifeforms in *the entire universe*, but given that that is way way bigger than the visible universe, we might still be very alone in our visible universe!

Note that even a much smaller Drake result is still a very large number if considering the visible universe and not just our galaxy.

I tend to expect that Drake errored on the safe side [results too small] due to our naive and anthropic view of what life is and where it might be possible for intelligent life to exist, and for that matter, our anthropic view what makes intelligence possible.

Correction: I guess it could be that I really mean the application of Drake's equation. I don't recall how specific some of his language was. For example, does intelligent life require an earth-like planet in order to evolve?

 

[HallsofIvy]

http://video.google.com/videoplay?docid=-5594744703753734741

Bearing in mind this post by Ivan in the UFO stickied thread.

10,000,000,000,000,000,000,000 stars in the universe, a very conservative estimate but let's assume it's correct.

And the Drake equation is possible given the criteria and confirms there must be intelligent life: maybe in the galaxy, but definitely in the universe by the laws of probability.

http://www.activemind.com/Mysterious/Topics/SETI/drake_equation.html

The Drake equation does not confirm anything. I notice that at the sight you cite, the note that each coefficient could be "from 0 to 100%" but then allow you to enter no value less that 0.0001%. Is there any reason to think that the real values are not far less than that? I don't think there is any reason expect any range of values! We just don't have the information.

And apply this to the universe, in a sort of what if way assuming this is fairly typical.

My question is two fold, we're fairly certain that probability indicates there must be life elsewhere in the universe, and assuming evolution works in simiilar if not the same ways elsewhere: it's fair to claim that their is intelligent life, so we accept life is out there? Yes/no?

Now given the conclusion is yes, do you think the intelligent life has visited Earth?

Since we have no reason whatever to assign even approximate values in the Drake equation, we certainly have no reason to "accept life is out there".

 

[DaveC426913]

each coefficient could be "from 0 to 100%" but then allow you to enter no value less that 0.0001%. Is there any reason to think that the real values are not far less than that?

No, but there's no point in calculating the results with those numbers. The chances come out < 1 : 10^-20.

 

[vanesch]

I tend to expect that Drake errored on the safe side [results too small] due to our naive and anthropic view of what life is and where it might be possible for intelligent life to exist, and for that matter, our anthropic view what makes intelligence possible.

Correction: I guess it could be that I really mean the application of Drake's equation. I don't recall how specific some of his language was. For example, does intelligent life require an earth-like planet in order to evolve?

Yes, but there are numbers in there which are totally out of the blue. For instance, "the probability to devellop microbial life on an earth-like planet". What if it is 10^(-30) ? Also, the "probability for intelligent life to devellop on an earth-like planet where microbial life develloped"... what if that equals 10^(-200) ?

Again, the fact that it happened on OUR planet shouldn't be factored in, because OF COURSE it happened on our planet. Each being wondering about it will be living on a planet where intelligent life devellopped. That says NOTHING about the probability for such an event to occur. So if we take that single and biased event out of our bag of observations, we have no indication at all that such a thing happens. The only thing we know is that it is physically possible for it to happen. But even if the probability for intelligent life to devellop equals 10^(-30000), there wouldn't be any problem for us to be here.

 

[Schrodinger's Dog]

The Drake equation does not confirm anything. I notice that at the sight you cite, the note that each coefficient could be "from 0 to 100%" but then allow you to enter no value less that 0.0001%. Is there any reason to think that the real values are not far less than that? I don't think there is any reason expect any range of values! We just don't have the information. Since we have no reason whatever to assign even approximate values in the Drake equation, we certainly have no reason to "accept life is out there".

Well for a start I'm clearly asking you to make the asumption that it does, in order to encourage debate, if we accept that it may provide an answer x.

Also I have clearly said that if you want to assign values to it that are other than the x on this site, you can there are plenty of sites out there, now taking x, do you think y?

http://www.seti.org/site/pp.asp?c=ktJ2J9MMIsE&b=179074

Knock yourself out

It was meant to stimulate debate, not to be picked apart, it is if we assume x then y?

OK have I clarified?

I have already sated quite clearly that Drake equations only use is in prompting the asking of questions, I asked a question? I'm not sure what that guy's going on about with it being useful, no it's not meant to be useful in a real scientific sense it's meant to be abstract by definition, but that doesn't make it of no use in a philosophical sense. Therefore given that can we move on now, no it is of no scientific value exactly, we know.

Since no one here knows the answer for sure, then that's pretty much what the discussion is about, what do you believe the likelihood is of meeting alien life given x or whatever you like really but given x as starter, now in the future or wherever you want to take the OP.

 

[PIT2]

That was not meant as a sleight. I'm just trying to determine if you do think we have indeed been visited. i.e. if you had to bet your life on it, on which side would you bet?

My bet would be on the visiting aliens.

 

[DaveC426913]

My bet would be on the visiting aliens.

OK. What fraction of current unexplained sightings would you attribute to bona fide alien craft encounters?

We can probably categorize unexplained encounter in broad groups (I'm sure they already are), from "lights in the sky" all the way up to "extensive video footage of craft in flight" and beyond.

How would you (if you had to bet) divide them up?

 

[PIT2]

OK. What fraction of current unexplained sightings would you attribute to bona fide alien craft encounters?

We can probably categorize unexplained encounter in broad groups (I'm sure they already are), from "lights in the sky" all the way up to "extensive video footage of craft in flight" and beyond.

How would you (if you had to bet) divide them up?

I don't know the numbers, so a fraction is hard to guess. The group that makes me bet on aliens is the one where there are multiple witnesses(which can be judged according to various criteria), as well as physical evidence(which can also be judged). Obviously the less criteria a sighting satisfies, the less convincing i find it. I guess we can also safely say that, if the upperclass sightings are aliens, then some percentage of the sightings in lower classes would be aliens also.

 

[Ivan Seeking]

Yes, but there are numbers in there which are totally out of the blue. For instance, "the probability to devellop microbial life on an earth-like planet". What if it is 10^(-30) ? Also, the "probability for intelligent life to devellop on an earth-like planet where microbial life develloped"... what if that equals 10^(-200) ?

Again, the fact that it happened on OUR planet shouldn't be factored in, because OF COURSE it happened on our planet. Each being wondering about it will be living on a planet where intelligent life devellopped. That says NOTHING about the probability for such an event to occur. So if we take that single and biased event out of our bag of observations, we have no indication at all that such a thing happens. The only thing we know is that it is physically possible for it to happen. But even if the probability for intelligent life to devellop equals 10^(-30000), there wouldn't be any problem for us to be here.

I agree; our existence might be against all odds, however there is no evidence to suggest that this is true. Also, since there is no reason to believe that we are special, it is entirely possible that intelligent life is nearly as common as planets.

If we randomly select a grain of sand on the beach, is it more logical to expect that grain of sand to be unique, or typical. Does our observation of that grain change the odds? Were the odds for intelligent life on Earth different before we [humans] came to be? Unless we can cite reasons why we are unique, it seems to me that our very existence is evidence that life is common. Again, the only hard evidence for the odds is measured as 1:1, for intelligent life on earth-like planets.

 

[Ivan Seeking]

The ending of http://www.youtube.com/watch?v=9JSR_6qfXTg" seems appropriate.

Most excellent!

Note however the contradiction with inflation theory when citing the expansion rate limit. Dont we need to make a small change - the speed of light is not the fastest speed there is?

 

[arildno]

Are you hoping someone will beg you to share your wisdom? Or do you just have a whim to poop on an otherwise perfectly good discussion?

A discussion that at the outset respects the Drake equation as something more than worthless is, quite simply, not a "perfectly good discussion".

And, it is worthless, because most of the parameters involved in it is indeterminable (at present).

 

[arildno]

I agree; our existence might be against all odds, however there is no evidence to suggest that this is true. Also, since there is no reason to believe that we are special, it is entirely possible that intelligent life is nearly as common as planets.

If we randomly select a grain of sand on the beach, is it more logical to expect that grain of sand to be unique, or typical. Does our observation of that grain change the odds? Were the odds for intelligent life on Earth different before we [humans] came to be? Unless we can cite reasons why we are unique, it seems to me that our very existence is evidence that life is common. Again, the only hard evidence for the odds is measured as 1:1, for intelligent life on earth-like planets.

Since the fact that we are alive means that the conditions for life necessarily must be present in our case, HOWEVER RARELY FULFILLED those conditions are, the example of ourselves gives us no clue whatsoever as to the prevalence of those conditions in the universe as such.

 

[Ivan Seeking]

Odds for any planet to be an Earth-like planet;, based on the evidence - 1:9. Correct? And we hope to find life on Europa - a moon, not a planet. So it seems that we also have to include moons in the calculations.

Or should we assume that we are a fluke given no evidence that our system is unique? I don't see the logic in that. Again, it seems to me that what we do know suggests that life may be very common.

 

[arildno]

1:9 is not correct. We have found several other planets as well, none of which are Earthlike.

 

[Ivan Seeking]

Can we detect earth-like planets yet?

 

[arildno]

By occultations perhaps, I dunno.

 

[Ivan Seeking]

I don't think we're quite there yet. The last the I saw, we can only detect relatively large planets, like Jupiter. And I recall the comment being made that this [finding Jupiters] is a very good sign because large planets make life on smaller planets possible by clearing the system. So finding big planets bodes well for life.

 

[arildno]

That I happen to share the same sentiment as you in believing that there are lots and lots of planets out there with life, I'm quite simply stating that we cannot logically extrapolate from a single instance we know of to the probability of its universal occurrence.

 

[Ivan Seeking]

That I happen to share the same sentiment as you in believing that there are lots and lots of planets out there with life, I'm quite simply stating that we cannot logically extrapolate from a single instance we know of to the probability of its universal occurrence.

I realize that. Perhaps I misstated things a bit. My point is that so far there is no evidence to back the agument that life is likely rare. I think we should expect that life is common based on what we know today.

edit: Or, maybe it would be better to say that there is more reason to expect life than not.

Also, with our one example of our solar system, let's not forget about the water on Mars.

 

[DaveC426913]

A discussion that at the outset respects the Drake equation as something more than worthless is, quite simply, not a "perfectly good discussion".

For one, so good of you to join us. For two, you're using circular logic; the discussion is perfectly good until someone steps up and shows why it isn't.

The Drake equation may not be rigorously scientific, granted, but that doesn't make it worthless.

It does not attempt to provide an answer, it attempts to give structure to our educated guesses. Some are more education, some are more guess. But the fact is, we DO know how many stars there are our galaxy, and we are starting to get a pretty good idea of how many of those stars have planetary systems, and we can consider each variable in turn, with increasing speculation on hte way down.

But it is still better at helping us weigh our odds than "somewhere between 1 and 1 billion".