Chance of Life Elsewhere

[HP]

Okay, some one tell me if this makes sense:

The chance a random planet (that's not Earth) has life in it is p

p is non-zero

The number of planets in the Universe is say N

So the chance of life elsewhere is 1-(1-p)^N

Okay so how many planets are there? Well, in the observable Universe, we've detected like a 100 (I'm out of date though, this was like 4 years ago). What about the rest of the Universe? There is no limit to the number of planets there could exist.

The only thing we can say is there is at least 100 planets.

Therefor we can only say the chance of life elsewhere is at least 1-(1-p)^100

So anyone claiming there is probably not life elsewhere is bit.... wrong, no?

This will work for any definition of life, as long as p is non-zero

[MrMon]

It's not exactly the same thing, but try:

Drake Equation

[HP]

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It's not exactly the same thing, but try:

Drake Equation

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The Drake equation states that:

N = R* × fp × ne × fl × fi × fc × L

where:

N is the number of civilizations in our galaxy, with which we might hope to be able to communicate;

and

R* is the rate of star formation in our galaxy
fp is the fraction of those stars that have planets
ne is the average number of planets that can potentially support life per star that has planets
fl is the fraction of the above that actually go on to develop life at some point
fi is the fraction of the above that actually go on to develop intelligent life
fc is the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L is the length of time such civilizations release detectable signals into space.

Yeah, so in the way he's done things, I would say that for R* one can only find a minimum. R* could be a googolplex or whatever

edit: woops nevermind, he was only looking at our galaxy, not the universe

[PairTheBoard]

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So anyone claiming there is probably not life elsewhere is bit.... wrong, no?


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Just because you figure there is some chance does not mean you can't conclude there is "probably not".

PairTheBoard

[HP]

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Just because you figure there is some chance does not mean you can't conclude there is "probably not".

PairTheBoard

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why not?

[PairTheBoard]

[ QUOTE ]
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Just because you figure there is some chance does not mean you can't conclude there is "probably not".

PairTheBoard

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why not?

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Suppose the "some chance" you figure is 1 in a googolplex. Even though there is then "some chance" you would still say it's "probably not" the case.

PairTheBoard

[HP]

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Suppose the "some chance" you figure is 1 in a googolplex. Even though there is then "some chance" you would still say it's "probably not" the case.

PairTheBoard

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why? This would imply you are confident the Universe contains less than ~1 googolplex planets. I don't see how you could say that

[mjkidd]

There ~ 10^11 galaxies in the universe, and about 10^11 stars/galaxy. Say 10 planets/star, and you get 10^23 planets. We are not off by a google orders of magnitude. Both a "google" and, particularly, a "googleplex" are absurdly large numbers that should never be mentioned. There aren't a google of anything in the universe, let alone a googleplex.

[FortunaMaximus]

[ QUOTE ]
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Suppose the "some chance" you figure is 1 in a googolplex. Even though there is then "some chance" you would still say it's "probably not" the case.

PairTheBoard

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why? This would imply you are confident the Universe contains less than ~1 googolplex planets. I don't see how you could say that

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It's a reasonable assumption to make based on known information.

If you plug different values into the Drake equation, you're going to get a wide range of answers. The last 4 elements in the equation are mere guesswork. But you'll get a range. Best ya can do, really, and unless you introduce an element of improbability by giving a value of 0 to an element, you're gonna get the obvious result.

So the answer's non-zero. That and the Fermi Paradox (wtf, they ain't here yet? Where are they? in short) makes it an interesting puzzle. All you can do is define the problem and make better guesses.

[PairTheBoard]

[ QUOTE ]
[ QUOTE ]
Suppose the "some chance" you figure is 1 in a googolplex. Even though there is then "some chance" you would still say it's "probably not" the case.

PairTheBoard

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why? This would imply you are confident the Universe contains less than ~1 googolplex planets. I don't see how you could say that

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Estimates are that there are fewer than a googolplex atoms in the Universe.

Besides that, you are engaging in a fallacy if you insist on no upper bound for the unknown number of planets but declare a lower bound for the unknown probability that a random one contains life. Until you decide on some actual numbers your argument goes nowhere.

PairTheBoard