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

[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".

 

[Ivan Seeking]

Of course, as Vanesch was pointing out, this also boils down to the question of the source of life. Is it all in the odds - a one in a trillion chance - or is life raining down from the heavens on comets or other heavenly bodies, in our own primordial past? In our crudest form were we ETs? Or, could life be enevitable given enough time, the correct chemistry, and a source of energy? Also, might there be something else that drives life into existence wherever possible?

 

[DaveC426913]

When I break it down and ask myself about the very beginnings, where amino acids first began forming proteins, it seems to me (irrationally) that, as long as you have the key ingredients, it's a high probability.

key ingredients:
- liquid water (and, by logical induction, energy, usually solar, but also, apparently, electrical)
- organic compounds
- time
An abundance of each of the above.


I guess that abundance thing can't be underestimated. Small or seasonal puddles (as opposed to oceans) would vastly retard the formation of life.

Can anyone think of any other requirements?

 

[fournier17]

When I break it down and ask myself about the very beginnings, where amino acids first began forming proteins, it seems to me (irrationally) that, as long as you have the key ingredients, it's a high probability.

key ingredients:
- liquid water (and, by logical induction, energy, usually solar, but also, apparently, electrical)
- organic compounds
- time
An abundance of each of the above.


I guess that abundance thing can't be underestimated. Small or seasonal puddles (as opposed to oceans) would vastly retard the formation of life.

Can anyone think of any other requirements?

I just learned about chemical evolution in my cell and molecular biology class. Basically it is believed that Earth's ancient atmosphere, contained inorganic compounds such as nitrogen gas, carbon dioxide, water, hydrogen gas, ammonia, and methane. When you apply electricity to these inorganic compounds in a container, you spontaneously get organic compounds, even amino acids. When you add clay into the picture, which there was a lot of in early earth, scientist have seen the spontaneous synthesis of larger molecules like protiens, and small strands of RNA and DNA. The fact that you can get RNA from having the conditions that were believed to be present in early Earth, is AMAZING because it is believed that RNA was the first self replicating molecule, which gave rise to biological evolution. Now if scientist can create organic molecules from inorganic compounds during an experiment, its going to happen in other parts of the universe that has the right conditions

What I believe is needed for life to evolve is:
1.) Inorganic compounds listed above
2.) A source of energy
3.) Water is essential
4.) And a surface
5.) The planet that has potential for evolution, has to be within a certain range of a star.
6.) A large amount of time in between catastrophic events like asteriod strikes. This is were huge planets like Jupiter come into play. It is believed that Jupiter deflected a lot of asteriod strikes which gave life on Earth time to evolve. I think if the Asteriod that took out the dinosaurs didnt strike earth, this planet would have evolved a reptellian intelligent species, or maybe even a bird like intelligent species. If it wasnt for that perticular asteriod strike that took out the dinosaurs, we would not be here today.

 

[Ivan Seeking]

NASA scientists today announced the creation of amino acids, critical for life, in an environment that mimics deep space. The research will be published in the March 28 [2002] issue of the journal Nature.

In a laboratory at NASA Ames Research Center in California's Silicon Valley, the team of astrobiologists shone ultraviolet light on deep-space-like "ices," simulating conditions that are commonplace in interstellar space. Deep-space ice is common water ice laced with simple molecules. The team subsequently discovered amino acids, molecules present in, and essential for, life on Earth.

"This finding may shed light on the origin of life itself," said Dr. Max Bernstein, the first author and chemist at NASA Ames and the Search for Extraterrestrial Intelligence (SETI) Institute. "We found that amino acids can be made in the dense interstellar clouds where planetary systems and stars are made. Our experiments suggest that amino acids should be everywhere, wherever there are stars and planets." [continued]

http://web99.arc.nasa.gov/~astrochm/pr.html
The paper
http://www.astrochem.org/PDF/Bernsteinetal2002.pdf
More reading
http://web99.arc.nasa.gov/~astrochm/reading.html

Also, in addition to Mars and Europa, we need to mention the moon Titan as another candidate in our own solar system that might be capable of supporting life.

 

[arildno]

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

That is, indeed, a very important find.
Even more exciting, though, will it be to explore Europa.

And, as it happens, we may not need to travel that far to see if life can subsist in water beneath a perennial layer of ice:
There exist buried lakes on Antarctica, it would be thrilling to find out if there is life in them.

 

[Azael]

When you add clay into the picture, which there was a lot of in early earth, scientist have seen the spontaneous synthesis of larger molecules like protiens, and small strands of RNA and DNA. The fact that you can get RNA from having the conditions that were believed to be present in early Earth, is AMAZING because it is believed that RNA was the first self replicating molecule, which gave rise to biological evolution.

Has the spontaneous formation of RNA really been observed or is just a hypothesis that it could happen that way?

 

[Schrodinger's Dog]

Can we detect earth-like planets yet?

Interferometers are meant to be able to detect the wavelength of light (such as the green of clorophyl) That when you filter out the vast light of the sun could indicate life, but there aren't any big enough to do this yet AFAIK.

 

[SqrachMasda]

there should be
i can't even imagine a 4th dimension
and dolphins don't seem to recognize out existence

haha
pretty much if there is something else
it may be right in front of us, or watching us and know everything about us
and we have no clue about it

 

[DaveC426913]

What I believe is needed for life to evolve is:
1.) Inorganic compounds listed above
2.) A source of energy
3.) Water is essential
4.) And a surface
5.) The planet that has potential for evolution, has to be within a certain range of a star.
6.) A large amount of time in between catastrophic events like asteriod strikes.

1] Unless I'm mistaken, CO2 and methane are both organic compounds.

2]
IMO, you're over-complicating it the requirements.
- For water to be liquid, there must be enough energy to make it so. Sufficuent energy is a given.
- No surface is needed. Oceans work nicely.
- The range from the parent star is covered under the "liquid water" requirement. It is not in-and-of-itself a requirement.
- I don't think a large amount of time betwwen catastrophes is a requirement. We're just talking about the origin of life for now, not the evolution of complex organisms. I doubt the biggest asteroid could wipe out ocean life across a planet.

 

[fournier17]

Has the spontaneous formation of RNA really been observed or is just a hypothesis that it could happen that way?

Follow up experiments of the Urey and Miller experiment, were conducted with clay added into the mix of gases. RNA did polymerize spontaneously, but only in the presence of specific clay. In the presence of certain minerals, amino acids formed at least 50 monomer protiens. Some of the protiens that formed had catalytic activity such as ATPase, catalase, and perixodase.