Thread: Do you beleive in . . . aliens?

Originally Posted by Sandform

When a person says are their aliens out there, few people mean are there plants out there? Are there single celled organisms out there?

Gee, that's what I mean. I'm not sure why you think technology is so important in the grand scheme of things. Hell, an alien civilization may not even use technology. They may be more Zerg-like. Ever considered that?

Originally Posted by drewmandan

Gee, that's what I mean. I'm not sure why you think technology is so important in the grand scheme of things. Hell, an alien civilization may not even use technology. They may be more Zerg-like. Ever considered that?

I never said technology was important...
The only person who even mentioned technology was Scatterbrain.

There are many things I have "considered."

If you are speaking to me, do not create a point which I do not stand on and then argue against it.

If we do find life on another planet, I do not assume that they would only have one quality such as being "zerg like." I happen to think that it is likely that any planet with one form of life has many other forms as well, and they will most likely be as diversified as ours, assuming that any life on that planet has developed consciousness.

Originally Posted by Sandform

consciousness.

Well, I assumed that when you used this word the way you did, you were referring to the human variety of "consciousness", but I happen to believe that all animals are conscious.

Originally Posted by drewmandan

Well, I assumed that when you used this word the way you did, you were referring to the human variety of "consciousness", but I happen to believe that all animals are conscious.

I agree, I believe that all animals are conscious as well. Anything capable of thought, I would assume, has consciousness. I'm not aware of very many definitions that would exclude an animal from consciousness, unless it is something like being aware of specific things, like how someone can be conscious of how their actions may affect other things.

I'm not sure where you thought I was meaning human consciousness only, I tried to make it a point that I was referring to animal life, at least on our planet, I suppose there are alternatives to ways in which consciousness could arise without it being animal life, though that is one objective I must have failed to accomplish.

Well, animal life didn't take very long either. They arose about 610 mya, but multicellular life in general was about 1.2 bya, so that's only 600 million years to go from basically a tumor to an animal with a brain. That's really fast.

Originally Posted by drewmandan

Well, animal life didn't take very long either. They arose about 610 mya, but multicellular life in general was about 1.2 bya, so that's only 600 million years to go from basically a tumor to an animal with a brain. That's really fast.

Yes, 600 million years is fast...but it was quite some time from the formation of the planet to the time when animal life began to spring up.

My argument is that we don't know how long life will exist. If life on Earth were to die for some reason, even within say a million years from now, that would mean that some other form of life would have to exist within the same 700 million years or so span that another planet with life existed.

So my argument is that I think life existing elsewhere is possible, but that it would necessarily exist within the same time frame as life on our planet, I can't say I view it as more "likely" than not, though I do view it as possible.

So it isn't to say it is unlikely that life exists somewhere else, right now, but instead that I haven't been presented with evidence that would lead me to conclude that it is more likely that life must exist within the same time frame as our own.

Originally Posted by Sandform

Yes, 600 million years is fast...but it was quite some time from the formation of the planet to the time when animal life began to spring up.

My argument is that we don't know how long life will exist. If life on Earth were to die for some reason, even within say a million years from now, that would mean that some other form of life would have to exist within the same 700 million years or so span that another planet with life existed.

So my argument is that I think life existing elsewhere is possible, but that it would necessarily exist within the same time frame as life on our planet, I can't say I view it as more "likely" than not, though I do view it as possible.

So it isn't to say it is unlikely that life exists somewhere else, right now, but instead that I haven't been presented with evidence that would lead me to conclude that it is more likely that life must exist within the same time frame as our own.

Well, first of all, there have been lots of mass extinctions on Earth and none of them killed off all animal life. Second, even if animal life typically lasted only 1% of the life of the planet (which life on Earth has greatly exceeded already), then you're comparing that 1% to billions of planets.

For example, to be assured a 99.999% chance of another planet capable of life actually having life at this moment, assuming that life exists for 1% the life of the planet, you would need only sample about 1,140 planets.

For a 99.9999999% chance, you require about 2,050 planets.

How many Earth-like planets are there in our galaxy, let alone in the observable universe? More than 2,000 I would bet.

Originally Posted by drewmandan

Well, first of all, there have been lots of mass extinctions on Earth and none of them killed off all animal life. Second, even if animal life typically lasted only 1% of the life of the planet (which life on Earth has greatly exceeded already), then you're comparing that 1% to billions of planets.

For example, to be assured a 99.999% chance of another planet capable of life actually having life at this moment, assuming that life exists for 1% the life of the planet, you would need only sample about 1,140 planets.

For a 99.9999999% chance, you require about 2,050 planets.

How many Earth-like planets are there in our galaxy, let alone in the observable universe? More than 2,000 I would bet.

Where are you getting these chance figures from?

Originally Posted by Sandform

Where are you getting these chance figures from?

Which version of the word life are you using?

I was thinking about animal life. If you want the numbers for technological life, I can calculate those too. They won't be much different.

The figures are derived from the axioms of probability, namely that the chance of something not happening is exactly 1-(chance of it happening). Thus, the chance of finding life (whatever your definition) is:

chance of life = 1 - (chance of no life)^n, where n is # of planets sampled. Re-arrange for n, and you get:

n = [ ln (1-(chance of life)) ] / [ ln (chance of no life) ]

Plug in desired chance of life after all the sampling of 99.999%, chance of no life on any given planet as 99%, and you get 1,140.

Originally Posted by drewmandan

I was thinking about animal life. If you want the numbers for technological life, I can calculate those too. They won't be much different.

The figures are derived from the axioms of probability, namely that the chance of something not happening is exactly 1-(chance of it happening). Thus, the chance of finding life (whatever your definition) is:

chance of life = 1 - (chance of no life)^n, where n is # of planets sampled. Re-arrange for n, and you get:

n = [ ln (1-(chance of life)) ] / [ ln (chance of no life) ]

Plug in desired chance of life after all the sampling of 99.999%, chance of no life on any given planet as 99%, and you get 1,140.

But you don't know what the actual chance percent is. "Plug in the desired chance for life." You are making up a chance percent, so all you have done is say IF the chances of no life on other planets were 99%, and the chances of life were 99.9999999% then you would only require 2,050 planets (for that chance). Somewhere in here you are created a % from something without a basis. If I'm reading it correctly, you are assuming a number for the chance of no life.

The chances of life existing are pointless if you are creating a fictitious number for the chance of no life.

For all you know the "chance" percent could equal the exact amount for only 1 planet to have life.

Furthermore science can not make predictions for something based on a single occurrence. The only life we know of at the moment is life on Earth.

Your figures are deceiving, because they assume that the chances are something, and you couldn't possible know that something.

Originally Posted by Sandform

But you don't know what the actual chance percent is. "Plug in the desired chance for life." You are making up a chance percent, so all you have done is say IF the chances of no life on other planets were 99%, and the chances of life were 99.9999999% then you would only require 2,050 planets. Somewhere in here you are created a % from something without a basis. If I'm reading it correctly, you are assuming a number for the chance of no life.

You're not reading it correctly. Let me give an example.

Let's say you have 4 coins, and you flip all of them. They can each land either heads or tails. Let's say you wanted to know the chance of getting at least 1 head. This chance is 1-(chance of no heads). Now, the only way to get no heads is to get all tails, and the probability of that is (1/2)^4 = 1/16. So the chance of at least 1 head is 1- 1/16 = 15/16.

Now, say you have n coins. By the same logic as above, the chance of getting at least one head is 1-(1/2)^n.

Following this?

Instead of coins, let's say you're rolling dice, and you want the chance of at least one 6 coming up. Now this chance is

1 - (chance of no 6)^n = 1 - (5/6)^n

Now, what if you wanted to specify the chance of getting at least one 6 to a chance of your choosing (call it X)? Then you must calculate the number of rolls you would need (n) to be able to say beforehand that your chance of at least one 6 is X.

So n = ln(1-X) / ln(5/6), just from rearranging.

Now, in the case of planets, we are assuming extremely conservatively that animal life lasts only 1% of the life of a planet, meaning any given planet has only a 1% chance of having life at any given time. And then all I did was to pick a desired chance of, out of all the planets we plan to survey, just at least 1 of them having life. I picked two examples for this number, both of which ridiculously close to 100%.

The result is that if the chance of any given planet having life is only 1%, then if you surveyed 1,140 planets, there would be a 99.999% chance that at least 1 had life.

Originally Posted by drewmandan

You're not reading it correctly. Let me give an example.

Let's say you have 4 coins, and you flip all of them. They can each land either heads or tails. Let's say you wanted to know the chance of getting at least 1 head. This chance is 1-(chance of no heads). Now, the only way to get no heads is to get all tails, and the probability of that is (1/2)^4 = 1/16. So the chance of at least 1 head is 1- 1/16 = 15/16.

Now, say you have n coins. By the same logic as above, the chance of getting at least one head is 1-(1/2)^n.

Following this?

Instead of coins, let's say you're rolling dice, and you want the chance of at least one 6 coming up. Now this chance is

1 - (chance of no 6)^n = 1 - (5/6)^n

Now, what if you wanted to specify the chance of getting at least one 6 to a chance of your choosing (call it X)? Then you must calculate the number of rolls you would need (n) to be able to say beforehand that your chance of at least one 6 is X.

So n = ln(1-X) / ln(5/6), just from rearranging.

Now, in the case of planets, we are assuming extremely conservatively that animal life lasts only 1% of the life of a planet, meaning any given planet has only a 1% chance of having life at any given time. And then all I did was to pick a desired chance of, out of all the planets we plan to survey, just at least 1 of them having life. I picked two examples for this number, both of which ridiculously close to 100%.

The result is that if the chance of any given planet having life is only 1%, then if you surveyed 1,140 planets, there would be a 99.999% chance that at least 1 had life.

Ok, well I'm going to make a few statements about what you're saying, since you seem to be leaving out a bit of the reason it is relevant.

First, your 1% figure is of planets that have, have had, or will have life.
"assuming that life exists for 1% the life of the planet" This would mean you are saying of the planets that have life, and not of all planets in the universe, including planets that will never have life. So what you are "sampling" would be of planets that either have, will have, or do have, life. I suppose you could have been including all planets, even those which will never have life, but I don't think that is what you meant.

Second, you are ignoring the age of other planets in this equation, and instead are assuming the % of time that the life is on that planet in comparison to the age of the planet, without caring about the actual age that the planet is at the moment. This seems faulty, on a number of levels. The first being an assumption for the average length of time in which life must exist for planets that have never been observed, when there is only one case of life on a planet available for study. Also, in order for your equation to even have any relevance to the topic of concurrent life, the planets would have to be approximately the same age.

Originally Posted by me

If I'm reading it correctly, you are assuming a number for the chance of no life.

Originally Posted by Drew

we are assuming extremely conservatively that animal life lasts only 1% of the life of a planet

This is where you derived the 99% assumption right?

Originally Posted by Drew

chance of no life on any given planet as 99%

Just checking, because you said I wasn't reading it correctly when I said that.


The 1% is an assumption. This is the one number that in order for your equation to even matter has to be correct. You do not have enough information to make an assumption about this number. For all we know life on Earth could be extremely rare for the length of time it has carried on, after all the universe is a very disastrous place. You yourself have said that the planet has had various mass extinctions since it has existed. Who says we aren't the rarity and life has been cut short on other planets? There is no reason to assume that it couldn't be that the average length of time, when you are including the average from all of the planets with life, isn't much smaller.

If none of the three numbers are actually known numbers, then none of the equation matters, at all, at least until one of the numbers becomes known.

Neither the assumption that life is concurrent with other life or not concurrent is founded on any evidence, because we have no proof as of the moment as to how long life even exists per planet with life universally. To say otherwise would be dishonest.

I'm just kind of jumping in here, but I'm guessing this is just talking about the lifespan of a planet without natural distasters?

Originally Posted by Sandform

Ok, well I'm going to make a few statements about what you're saying, since you seem to be leaving out a bit of the reason it is relevant.

First, your 1% figure is of planets that have, have had, or will have life.
"assuming that life exists for 1% the life of the planet" This would mean you are saying of the planets that have life, and not of all planets in the universe, including planets that will never have life. So what you are "sampling" would be of planets that either have, will have, or do have, life. I suppose you could have been including all planets, even those which will never have life, but I don't think that is what you meant.

I'm talking about planets sufficiently similar to Earth to be what we would call "life capable". There are probably lots of these. A couple thousand is not an unreasonable number.

Originally Posted by Sandform

Second, you are ignoring the age of other planets in this equation, and instead are assuming the % of time that the life is on that planet in comparison to the age of the planet, without caring about the actual age that the planet is at the moment.

Please provide a mathematical example of this effect. I don't understand.

Originally Posted by Sandform

This seems faulty, on a number of levels. The first being an assumption for the average length of time in which life must exist for planets that have never been observed, when there is only one case of life on a planet available for study. Also, in order for your equation to even have any relevance to the topic of concurrent life, the planets would have to be approximately the same age.

First of all, the age of the planets doesn't come into it at all. Obviously, we wouldn't be sampling molten planets or planets about to be consumed by a red giant, but why would we? No one would mistake those for being Earth-like.

Originally Posted by Sandform

The 1% is an assumption. This is the one number that in order for your equation to even matter has to be correct.

Not true. It's actually quite insensitive to this number. I only picked 1% because it was ridiculously smaller than our example, which is Earth. Would you suggest another number?

Originally Posted by Sandform

You do not have enough information to make an assumption about this number. For all we know life on Earth could be extremely rare for the length of time it has carried on, after all the universe is a very disastrous place.

Occam's Razor.

Originally Posted by Sandform

You yourself have said that the planet has had various mass extinctions since it has existed. Who says we aren't the rarity and life has been cut short on other planets? There is no reason to assume that it couldn't be that the average length of time, when you are including the average from all of the planets with life, isn't much smaller.

Even if we assume mass extinctions are always deadly, they still only happen once every few hundred million years. That's way more than the 1%.

Originally Posted by Sandform

If none of the three numbers are actually known numbers, then none of the equation matters, at all, at least until one of the numbers becomes known.

Well, I clearly wasn't trying to make any actual predictions. I was merely trying to demonstrate that due to the logarithmic nature of the result, for there to not be life on any planet, the chance of life would have to be very small. Like... 1 in # protons in the universe...small.

Originally Posted by Sandform

Neither the assumption that life is concurrent with other life or not concurrent is founded on any evidence, because we have no proof as of the moment as to how long life even exists per planet with life universally. To say otherwise would be dishonest.

I didn't claim to know. Again, the 1% figure is irrelevant to the result. Plug in any number you wish.

Originally Posted by drewmandan

Well, I clearly wasn't trying to make any actual predictions. I was merely trying to demonstrate that due to the logarithmic nature of the result, for there to not be life on any planet, the chance of life would have to be very small. Like... 1 in # protons in the universe...small.

Well that is fine. But I know you know that in our universe such chances are possible, and there is no reason to assume that life is a special case where the chances of it happening can't be low.

For example, if Earth is the only planet with life on it, it would have to be wouldn't it?

Without more planets to study that have life, we can't make any predictions about the likelihood of anything. Why assume life special enough that it needs to happen more than once, or has to happen with such a high occurrence that life is concurrent with other life?

We don't even know how many Earth-like planets are out there.

In our minds, 1% may be low, but on a universal scale...such figures may actually be high.

Originally Posted by Sandform

Well that is fine. But I know you know that in our universe such chances are possible, and there is no reason to assume that life is a special case where the chances of it happening can't be low.

For example, if Earth is the only planet with life on it, it would have to be wouldn't it?

Without more planets to study that have life, we can't make any predictions about the likelihood of anything. Why assume life special enough that it needs to happen more than once, or has to happen with such a high occurrence that life is concurrent with other life?

We don't even know how many Earth-like planets are out there.

In our minds, 1% may be low, but on a universal scale...such figures may actually be high.

Yes but to say that there's no other life necessarily says that the chances of life are not 1%, not 0.1%, not even 0.00000001%, but way smaller than that. To put the chances that low seems completely unreasonable and based more on some sort of faith than science.

Originally Posted by drewmandan

Yes but to say that there's no other life necessarily says that the chances of life are not 1%, not 0.1%, not even 0.00000001%, but way smaller than that. To put the chances that low seems completely unreasonable and based more on some sort of faith than science.

Yes, to actually say the figures are in fact that low would be, at the moment. But to accept it as a possibility, isn't necessarily faith. I am perfectly willing to accept that there is life out there, right now, if we find it, but until then I can't honestly say I believe it is any more likely than there not being any.

Originally Posted by Sandform

Yes, to actually say the figures are in fact that low would be, at the moment. But to accept it as a possibility, isn't necessarily faith. I am perfectly willing to accept that there is life out there, right now, if we find it, but until then I can't honestly say I believe it is any more likely than there not being any.

In the future, when life is discovered to be common, people will look back on you and laugh.

Originally Posted by drewmandan

In the future, when life is discovered to be common, people will look back on you and laugh.

Why because I said I'm open to the possibility but I'm not taking a stand on it?

Yeah, I'm sure they will laugh so hard. I can just imagine, oh ahaha, he said if animal life existed it wouldn't necessarily have to be concurrent with our life, during a time when there was no evidence of other life in the universe, oh ahaha.

Originally Posted by Sandform

Why because I said I'm open to the possibility but I'm not taking a stand on it?

Yeah, I'm sure they will laugh so hard. I can just imagine, oh ahaha, he said if animal life existed it wouldn't necessarily have to be concurrent with our life, during a time when there was no evidence of other life in the universe, oh ahaha.

More like, he thought out of the quadrillions of rocky planets, it's just as likely as not that Earth is the only one with life...

Originally Posted by drewmandan

More like, he thought out of the quadrillions of rocky planets, it's just as likely as not that Earth is the only one with life...

No, that isn't my argument. My argument is that there is no reason to assume that if there is life on other planets that it has to be concurrent with our own.

Go ahead and construct a fictional world where you can pretend to be right after the fact, it has no relevancy here.

So you're saying that no planet in the entire universe has had life from 600 mya until now?

Originally Posted by drewmandan

So you're saying that no planet in the entire universe has had life from 600 mya until now?

No that is not my argument. My argument is that we have no evidence of life out there, so we certainly do not have evidence that there is life existing simultaneously with our own. There is no reason to say it is "likely" that any of these assertions you are making are true. That doesn't mean it is "unlikely" it simply means that you are the one making an unfounded assumption, the assumption being that there MUST be life out there.

Originally Posted by Sandform

No that is not my argument. My argument is that we have no evidence of life out there, so we certainly do not have evidence that there is life existing simultaneously with our own. There is no reason to say it is "likely" that any of these assertions you are making are true. That doesn't mean it is "unlikely" it simply means that you are the one making an unfounded assumption, the assumption being that there MUST be life out there.

We certainly don't have evidence that you won't quantum tunnel through the floor in the next 5 minutes, yet we believe it won't happen. The odds are about the same.