[Closed] are there aliens?

The chances of life forming on earth were small. Very small indeed. In a universe of limitless size that has existed since well before World War I. It was all just a bunch of chance and co-incidence that god created us. Some say the odds are nearly as long as Arsenal ever winning the Premier League again.

For that to have happened again somewhere else is both spectacularly unlikely but, somewhat conversely, entirely likely. And for it to happen during our brief flicker of intelligence puts the odds even higher.

It is both entirely impossible and completely likely in equal measure.

Possibly.

have I got that right?

No.

That wasn't where we started.

Graham's opening gambit was.

I can't see how it could be possible that we are the only life in the entire universe.

That seems fairly certain to me.

But several others have been just as adamant.

Anyone here fancy a trip to Titan?

I see I'm winning you round.

Nope sorry. Feel free to substitute "extremely likely" there is life with the tautology [i]"it is extremely unlikely that we are alone"[/i], if that makes my point clearer.

[i]"I can't see how it could be possible that we are the only life in the entire universe."[/i]

That's not to say it is [i]impossible[/i], but I personally can't see how it could possibly be the case given our current understandings.

There would have to be something uniquely special about Earth that hasn't happened on billions and billions of other planets over billions of years - and so far we have no evidence for that.

No one, in the history of the internet, has ever changed their mind due to a well reasoned argument being put forward on a forum.

I have - but it doesn't seem likely today 🙂

With the lottery, money goes into a pot.

Numbers are drawn.

Eventually someone wins.

You're talking about a church hall raffle. We're talking about a National Lottery draw where its perfectly possible to have no winners.

But the more tickets are bought in any given week, the more winners you can expect, regardless of the actual probability of any given ticket being a winner (ie any randomly picked planet supporting life).

The number of stars and galaxies is totally irrelevant.

What if we were the [i]only[/i] planet in the universe? or there were only two? or ten? or a hundred million? or .... ?

I heard that they mostly come at night. Mostly...

Steven Tyler is almost certainly an Alien

Even in the worst circumstances, eventually all of the combinations of numbers will be covered and the lottery will be won.

Ah so, if you buy enough [s]planets[/s] tickets then someone wins?
But I thought you said the number of [s]planets[/s] tickets didn't matter? 😀

I read G's position as "it seems that it's probable"

have I got that right?

Yes emsz, though possibly slightly stronger than that. More like "it seems that it's EXTREMELY probable"

So RPRT, rather than saying 'No it isn't' a lot, can you summarise your position because it's hard for a stupid thicko like me to follow your chain of reasoning at the moment.

Wasn't there a theory that life originated on Earth via a meteorite carrying bacteria/viruses?

portlyone - the strangely named panspermia
http://en.wikipedia.org/wiki/Panspermia

Could you explain why the number of stars and galaxies dont alter the odds?

Because we don't know what the probability of life on earth was before it happened.

We have nothing to extrapolate from.

If the chance of life occurring spontaneously is infinitesimally small, then even multiplying it by a very big number makes no difference. To all intents and purposes it would still be virtually zero chance.

In scientific terms, having a bigger number of stars planets would be akin to "turning the amp up to 11"

go look up the Fermi-Hart Paradox

I always kind of think if you go in your garden and pick up a rock, there might be an earwig under it.

I could study the earwig even up close and it would never be aware of my presence. I could completely re-arrange it's habitat and it still wouldn't be able to conceive that I was there doing it. I could squash it and it would never know to blame me. I certainly wouldn't bother trying to talk to it.

So if some superior race or beings were [i]that[/i] much more intelligent and enlightened than us happen to be around I don't see how we would be able to conceive of them anyway, much like the earwig and me in my garden.

You look like ET.

If the chance of life occurring spontaneously is infinitesimally small, then even multiplying it by a very big number makes no difference. To all intents and purposes it would still be virtually zero chance.

If it were "infinitesimally small" then we wouldn't be here.

Because we don't know what the probability of life on earth was before it happened.

Based on your lottery argument it was 1.0 wasn't it? 😀

So the sum as you see it is

Number of planets with life = Total number of planets in the universe that could potentially support life x probability of life actually evolving. And yes, if that probability is suitably small and the number of stars is suitably big then one possible answer to that is 1, ie. us. But why is that more or less likely than any other answer?

You're talking about a church hall raffle. We're talking about a National Lottery draw where its perfectly possible to have no winners.

No it's not.

You may not have a winner in one particular week, but eventually you will have a winner. Eventually all of the combinations will be covered and someone will win.

Even if we send probes to every planet in the universe it is possible that they will all come up -ve.

Based on your lottery argument it was 1.0 wasn't it?

I see there are people here who know even less about probability than Graham.

I see there are people here who know even less about probability than Graham.

[b]

Based on your lottery argument

'nuff said. 😉

You may not have a winner in one particular week, but eventually you will have a winner. Eventually all of the combinations will be covered and someone will win.

I'm talking about [i]one [/i]draw in [i]one [/i]week with [i]one [/i]set of tickets.

And even if you want to keep on drawing next week, and the week after, and on as long as you like, this...

Eventually all of the combinations will be covered and someone will win.

...is still wrong, sorry 🙂

Ahha! I've got it rightplacerighttime works for MiB, quick everyone put on you shades before the bright light come through your monitor.

Can I clarify the lottery thing because it seems to be causing confusion.

I said:

Winning the lottery is quite unlikely, but somewhat less so if you buy 50,000,000,000,000,000,000,000 tickets (estimated number of stars in the universe).

What I meant by that flippant remark is that for ONE DRAW of the National Lottery there [i]could[/i] be 50,000,000,000,000,000,000,000 tickets sold and still no jackpot winner!

But I think everyone would agree that is highly unlikely - even though the odds of your one ticket winning are very small (1 in 13,983,816), it would be quite amazing if there wasn't a large number of winners from that number of entrants.

i.e. the number of planets/tickets clearly [i]does[/i] alter the overall odds of a successful outcome.

Don't forget time, that multiplies it by another huge number so even more likely

I am very happy with the comment "it is extremely unlikely that we are alone"

Intelligent alien lifeforms in "can't be arsed to talk to humanity" shocker.

They could ask us a lot - "what tyres for space?"

Would a spaceship take off on a conveyor belt & how to vent post picolax waste in space 🙂

Should we employ translators for aliens in NHS hospitals?

The probability of winning the national lottery is roughly 1 in 14 million for each draw for a single ticket. Previous draws not being won do not change the probability of future draws (thinking otherwise is known as the Gamblers Paradox)

Because of the random way that numbers are picked for each draw there is no guarantee that all the combinations will be covered for any draw so the probability is never 1. But the probability become lower as more tickets are bought (Think Graham S has explained this pretty well too)

We don't know the probabilty of life forming on Earth but as we are here discussing it (that would be the Anthropic principle) we know its higher than zero. Therefore having lots of Galaxies / stars / planets etc will obviously shorten the odds to argue otherwise is pointless

Aliens must exist , who else would buy those pig ugly bikes from Orange??

infinitesimally small

/grinds teeth

😉

If the chance of life occurring spontaneously is infinitesimally small, then even multiplying it by a very big number makes no difference. To all intents and purposes it would still be virtually zero chance.

In scientific terms, having a bigger number of stars planets would be akin to "turning the amp up to 11"

That is just stupid, Does buying more lottery tickets not alter your odds of winning?
It's so funny you mock us for our comprehension of probabilities… I thought troll at first tbh.

I see there are people here who know even less about probability than Graham.

The number of stars and galaxies is totally irrelevant.

I dont really understand why you are arguing this TBH it seems obvious tyhat it does, at the very least, alter the odds

Because of the random way that numbers are picked for each draw there is no guarantee that all the combinations will be covered for any draw so the probability is never 1. But the probability become lower as more tickets are bought (Think Graham S has explained this pretty well too)

It would get to 1 because of "lucky dip" tickets, which select an unchosen combination if one is available.

But we are getting away from the main point.

Junkyard:

…do I really need to explain why that is poorly thought out?

Yes, you do.

The point about the alien life problem is that it can't be solved by theory. Empirical evidence is required and we have none. Until we get some, we are simply guessing.

so if I give you one chimp and one typewriter and I have infinite chimps and infinite typewriters our odds are the same of creating Shakespeare as nothing has changed

Are you suggesting that there are an infinite number of planets?

Is this a what tyre for olympus mons thread?

It would get to 1 because of "lucky dip" tickets, which select an unchosen combination if one is available.

[i]*nnnnnurk*[/i]

A brave attempt, but no. The Lucky Dip is randomly chosen. Doing anything else would violate the principles and rules governing a lottery.

'Lucky Dip®' means a Selection consisting of six different numbers which, instead of being selected by a Retail Player, are [u]selected on a random basis[/u] by the Company's Central Computer System on behalf of that player.
-- http://www.national-lottery.co.uk/player/p/help/playinginstore/gameprocedures/lotto.ftl

Are you suggesting that there are an infinite number of planets?

I guess there must be if the chance of life is [i]"infinitesimally small"[/i] 😀

Actually, sorry, I apologize wholeheartedly for my gross error.

I was wrong about the lucky dip thing.

However, the probability of winning would still eventually get to 1 as once the pot got big enough it would be worth someone buying a ticket with each combination.

But really, my point about the planets is important - do you think there are an infinite number or not?

The point about the alien life problem is that it can't be solved by theory. Empirical evidence is required

Right.

and we have none.

Wrong! as was repeatedly pointed out upthread, we have quite a lot of empirical evidence on (a) the conditions under which life can exist and (b) the number of places in the universe where those conditions might be present.

And both (a) and (b) are turning out to be much wider categories than anyone previously thought.

"Technology from a very advanced civilization will be indistinguishable from magic"

However, the probability of winning would still eventually get to 1 as once the pot got big enough it would be worth someone buying a ticket with each combination.

However, the probability of winning would still eventually get to 1 as once the pot got big enough it would be worth someone buying a ticket with each combination.

Possibly true*, but that's talking about multiple lottery draws, not a single draw (as I explained earlier).

(* it'd be a risky gamble. Say the pot was at 28 million and you had 14 million quid just sitting around. You could buy every ticket combination and be assured of winning the jackpot, plus all lower prizes - BUT you risk sharing it with other people and making a loss).

But really, my point about the planets is important - do you think there are an infinite number or not?

Nope. Current thinking is there are a VERY large number, but not infinite.

[i]Even if we send probes to every planet in the universe it is possible that they will all come up -ve.[/i]

this isn't true, there's at least one. Right?

Depends if you're looking for intelligent life emsz 😉

Even if we send probes to every planet in the universe it is possible that they will all come up -ve.

this isn't true, there's at least one. Right?

It doesn't matter.

Possibly true*, but that's talking about multiple lottery draws, not a single draw (as I explained earlier).

(* it'd be a risky gamble. Say the pot was at 28 million and you had 14 million quid just sitting around. You could buy every ticket combination and be assured of winning the jackpot, plus all lower prizes - BUT you risk sharing it with other people and making a loss).

What would anyone accept as evidence? So far we have had eyewitness reports,video footage,photos,radar returns,and physical traces left behind(high levels of radioactivity etc). If this evidence was used in any other kind of case there wouldnt be a question. It would be regarded as proven.

It doesn't matter.

I'm struggling to see how the fact that life has definitely arisen once in the universe (something that I hope everyone can agree on 😉 ) is inadmissible as evidence for life in the universe.

Please continue your point rightplace.
I agree there are not infinite planets.... so..?

If you want some numbers to use, [url= http://astrobiology.arc.nasa.gov/roadmap/g1.html ]NASA astrobiologists[/url] reckon, based on our current experience of what "habitable" means, that there are 10,000,000,000 habitable "Earth-like" planets in our galaxy and around 1,000,000,000,000,000,000,000 in the observable universe.

Erm..

It does matter.

I'm a beleiver in Aliens, nope, I am, and am of the thought that we've already been visited way back. To get to where we are I think some beings visited here, populated the planet for a short period of time, found us lot on here, mated, we evolved into what we currently are.
I think that the reason so many breakthroughs in science and the apreciation of the Arts have been so profound in the last 160years or so is due to human evolvemnt and our Brains capacity to be used more effectively, like it should be.

On Girl who sits on a desk across from me looks like a Grey.

You are Erich von Daniken AICMFP.

OK, to take the point about a finite number of planets. If we agree on that then we are getting somewhere.

What we don't know is what the chance of life spontaneously happening is. It could be vanishingly small.

What most of you seem to be concentrating on is the big number (of planets) but somehow you're not too bothered about how small the chance of life starting is. If it is a vanishingly small chance, then overall chances of finding alien life will also be vanishingly small.

The point is, that we can't know what that chance is because we've not observed it happening.

Chances are that in time, we may get a pretty good idea of what the big number is, but we have literally no idea what the small number might be.

What most of you seem to be concentrating on is the big number (of planets)

That's because it's kind of important.

I reckon most people would consider odds of, say, 1 in 1,000,000,000,000,000,000 to be "vanishingly small" but even that would give you 1,000 instances of extraterrestrial life in the observable universe. Obviously chances are they'd be too far away to ever contact, but that's another issue 🙂

Intelligent life hasn't got as far as Doncaster, so I doubt there will be any on planets in Galaxies Far, Far Away.

I reckon most people would consider odds of, say, 1 in 1,000,000,000,000,000,000 to be "vanishingly small"

It's not really a question of "what most people reckon" though is it?

This isn't the committee for the formation of alien lifeforms.

My point (still) is that no one knows, or can know, what the figure is. it is unknowable, and [i]may[/i] be very, very, very small.

But really, my point about the planets is important - do you think there are an infinite number or not?

The number of stars and galaxies is totally irrelevant

My point (still) is that no one knows, or can know, what the figure is. it is unknowable, and may be very, very, very small.

And mine is that even if it's very, very, very small there's probably still something out there because of the vast number of planets. Worst case: it's 1 in 1,000,000,000,000,000,000,000. I find that somewhat implausible.

I'm not arguing for certainty here (and I don't think anyone else is either), just for the balance of probabilities.

Junkyard,

When I said that the number of stars and galaxies was irrelevant I was kind of assuming that people would be thinking of a finite number - how large that number might be isn't important, but it is important that it is finite.

Then you started talking about an infinite number of chimps, which gave me cause to check that we were all indeed thinking of this problem within a finite universe.

Simple really.

So do you, Junkyard, think that there are a finite number of planets?

the balance of probabilities

Aaaaaaarggghhhhhhhh!

I'm just slapping myself on the forehead.

That Hubble telescope has a lot to answer for.

What we don't know is what the chance of life spontaneously happening is. It could be vanishingly small.

It [i]could[/i] be, but we don't have any reason to suspect that it is.

We have the estimate that there are 1,000,000,000,000,000,000,000 planets that pass the basic requirements of being habitable as we know it (e.g. orbiting a star at a distance that is not too hot/cold for liquid water). So we've already whittled down the field based on what prerequisites we [i]know[/i] are required.

Now it [i]could[/i] be that is [u]all[/u] that is required, and that most of those planets have, or had, or will have, life on them. Or it could be that other prerequisites are needed that we don't know about.

e.g. perhaps such planets need a seed event (such as being struck by a meteor containing bacteria or suitable amino acids, as suggested earlier) in which case time plays an important factor too: chances of getting hit by a meteor right this second are slim, but at any time in 13.7 billion years it is quite a bit higher!

At the end of the day I find it unlikely that life is a 1-in-sextillion (yes really) chance on planets that we know can support it.

So far we only have direct experience of one Earth-like planet, and that has plenty of life on it, so success rate is looking pretty good so far 😀

.
(to avoid confusion that last sentence is a joke)

It could be, but we don't have any reason to suspect that it is.

Or that it isn't.

Or that it isn't.

This isn't an argument it's just contradiction!

So RPRT are you just arguing over the error bars and caveats that are applied to statements like "I think it's very unlikely that the Earth is the only planet in the universe that is ever going to be capable of supporting life"?

Or that it isn't.

Now you're asking me to prove a negative.

Put it this way, so far we have no evidence that Earth is "special" or "unique" or that whatever mechanism created life on this planet wouldn't also work on other planets.

Or indeed that there aren't other forms of life possible that we are not even considering (i.e. non carbon-based) that are created in other ways.

thepurist,

Have you not read the thread?

About half way down the first page we had:

i think it would be both naive and arrogant to think in the near infinite expanse of space there wouldn't be another planet, perhaps thousands of planets, with intelligent life on them.

Followed by various other comments along the same lines.

That's not quite "arguing over the error bars"

I'm just slapping myself on the forehead.

Well, I did that when you said "infinitesimally small", so now we're even 😉

every smudge of light is a galaxy, each galaxy has billions of stars. It's a terrible waste of space if there's nothing else out there to enjoy it.

I can't even begin to contemplate something like that without boggling [i]my own mind[/i]. 🙂

Another way of looking at this...

Two people, one each end of a really long flat road. Given enough time they will probably see each other (assuming they don't die before they reach the passing point).

The same two people at opposite edges of an equally massive flat circle (in terms of square metres) and the chances of them seeing each other becomes much less as the paths they can take are no longer linear.

Then imagine the same two people at opposite edges of an equally massive but [i]mountainous[/i] circle and the chances of them seeing each other becomes even less than the previous situation.

mastiles_fanylion - Member
Another way of looking at this...

Two people, one each end of a really long flat road. Given enough time they will probably see each other (assuming they don't die before they reach the passing point).

The same two people at opposite edges of an equally massive flat circle (in terms of square metres) and the chances of them seeing each other becomes much less as the paths they can take are no longer linear.

Then imagine the same two people at opposite edges of an equally massive but mountainous circle and the chances of them seeing each other becomes even less than the previous situation.

I was keeping up until this point. Now I'm just confused.... 😉

Put it this way, so far we have no evidence that Earth is "special" or "unique" or that whatever mechanism created life on this planet wouldn't also work on other planets.

We do, i posted it earlier.
On earth, for complex animal life we need
- large moon (much larger than any other observed planets)
- plate tectonics (doesn't exist on any other observed planets)
- spinning core providing a sheild from radiation
- to be in a habital zone not only of the solar system but of the galaxy, where there are very few supernova or other events emitting harmful particles
- to have relatively few extinction level events.
..
the list goes on...

Theres also the problem of timescales. Does all life evolve into complex life?? Life existed on earth for 4 billion years, yet complex life only evolved around 600 million years ago, and humans only 200,000 years ago, and we've only had the technology to get into space for 60 or so!

In 600 million more years the earth will be sterile and long before that humans will be cease to exist, and thats if we survive any future extinction events which happen once every 100 million years or so.

This creates quite a narrow window to communicate with any other aliens.

m_f: no argument there. The chances of us being able to communicate with any life out there is incredibly tiny, even if life was abundant.

Currently we'd just have to hope they had better comms tech than us that did something outside our current understanding of physics. Otherwise our conversation will suffer from a slight 100 light-year satellite delay 😀

My boss says that apparently having a massive planet like Jupiter nearby is really important as well, but he's a bit vague, he saw a programme on the telly.

On earth, for complex animal life we need

For [u]complex animal life[/u] perhaps, though even then I'm not sure all of those are undisputed prerequisites (see the earlier point about microbes found surviving inside nuclear reactors for how previous assumptions are changing).

Saw the same programme - they were suggesting that Jupiter basically takes the hits from NEOs so we don't have to - basically Earth is hiding behind it's big brother, and we have the Moon nearby to mop up a lot of the stuff that Jupiter lets by.

Amazing set of coincidences, all to give us a meaningless existence 😀

m_f: no argument there. The chances of us being able to communicate with any life out there is incredibly tiny, even if life was abundant.

You've missed the point again Graham.

He was talking about me and you.

Thanks Horatio,

It's been very lonely out here in the endless void of the STW forum.

He was talking about me and you.

😀

Otherwise our conversation will suffer from a slight 100 light-year satellite delay

A bit like when I first used Skype on 56k dial-up...

Horatio: you said several times in your testimony that such features hadn't been seen on [i]"any other observed planets"[/i]?

Can you tell the court what percentage of the sextillion habitable planets we've been able to conclusively check for, say, "plate tectonics"?

[img] [/img]

I see. And would you consider that a statistically meaningful sample sir?

We do, i posted it earlier.
On earth, for complex animal life we need
- large moon (much larger than any other observed planets)
- plate tectonics (doesn't exist on any other observed planets)
- spinning core providing a sheild from radiation
- to be in a habital zone not only of the solar system but of the galaxy, where there are very few supernova or other events emitting harmful particles
- to have relatively few extinction level events.

Why are there things needed? the point is you cannot tell what would affect the unknown. Life forms based on an nitrogen cycle rather than a carbon one? cycle ? perfectly possible

This creates quite a narrow window to communicate with any other aliens.

When I said that the number of stars and galaxies was irrelevant I was kind of assuming that people would be thinking of a finite number - how large that number might be isn't important, but it is important that it is finite.

In essence the more planets the more chance of the correct conditions. That seems undebatable tbh.

Junkyard: I think his killer point was that the chance of life on a "habitable" planet is unknown and [i]could[/i] be less than 1 in sextillion (I love saying that number), or basically equal or less than 1-in-X where X is the number of planets.

So it's not so much that X doesn't matter, just that if you accept X is finite then the probability of life could be 1-in-X.

GrahamS - ah, but that *is* one possible outcome isn't it? The sort of elegant quirk that the universe plays now and again, where fiendishly complex processes yield the simplest equations.

All we need to accept that is some reason to believe that the current scientific consensus resulting from many published and peer reviewed papers is somehow wrong. It'd be abso-blummin-lutely brilliant if someone could smack a curveball into some pillar of science because that's the sort of thing that drives our understanding forward, but I can't see it coming from this thread. (Or rather I believe there's an [i]infinitesimally small[/i] chance that it will 😉 )

GrahamS - ah, but that *is* one possible outcome isn't it?

Yep. It is [i]possible[/i], which is why I said I don't have absolute faith in alien life and that "nothing is certain".

But... I don't see any evidence that suggests the figure is that low, and far cleverer men with nice beards, pointy heads, multiple degrees and NASA coffee mugs seem to agree.

It'd be abso-blummin-lutely brilliant if someone could smack a curveball into some pillar of science

Yep, that would be fun, though personally speaking I would find a definitive revelation that we are absolutely alone in the universe to be incredibly depressing.

Our last remaining hope would be that when Earth finally explodes, bits of our planet eventually make it to other habitable planets and have enough amino acids and genetic material to start the whole thing again.

That may even be how we got here...

rprt.. I'm not sure HH was actually agreeing with you though. 😉

Anyway...

There is one thing we know for absolute certainty, unless, as suggested earlier, we are indeed in a simulation... but even if were are, would it matter?

Right, the one thing we know for certain is that the probability of life on this planet is 1. We exist, there can't be much argument about that. (TJ? 😉 )

So, that means that the probability of life occuring at least somewhere in the universe is 1... (that's us for the hard of thinking)

Given that, I'd say that the chances for there being life on any particular planet are not infinitesimally small, otherwise we wouldn't be here.

So the question now is this, which of these is more likely:-

a) that the probability of life existing on a particular planet is exactly the right number for there to be only a single planet (ours) in the entire universe with life?

or

b) that the probability of life existing on a particular planet is any other number than the one above?

I know which I am putting my lottery money on this week!