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 Post subject: Are we alone in the universe?Posted: Tue, 27 Dec 2011 21:50:44 UTC
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Joined: Tue, 27 Dec 2011 21:34:46 UTC
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Ok, a question for you big thinkers out there: How big is the probability that we are the only living planet out there?

My answer is: if the universe is endless. There will be endless of planets like ours.

What do you think ?

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 Post subject: Re: Are we alone in the universe?Posted: Tue, 27 Dec 2011 22:02:19 UTC
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This belongs in Miscellaneous. Topic moved.

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 Post subject: Re: Are we alone in the universe?Posted: Tue, 27 Dec 2011 22:04:10 UTC
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tomsharks wrote:
Ok, a question for you big thinkers out there: How big is the probability that we are the only living planet out there?

My answer is: if the universe is endless. There will be endless of planets like ours.

What do you think ?

Just to be clear, you know that this is a meaningless question from a mathematical point-of-view, right? It's fine to ask philosophical questions, but it's mostly pointless to ask on this site.

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 Post subject: Re: Are we alone in the universe?Posted: Fri, 30 Dec 2011 03:21:52 UTC
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tomsharks wrote:
My answer is: if the universe is endless. There will be endless of planets like ours.

Well, you can always use that as a "pickup line in disguise" at your favorite bar

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 Post subject: Re: Are we alone in the universe?Posted: Fri, 30 Dec 2011 03:59:04 UTC
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Hi there, maybe a mathematical idea does exist

http://en.wikipedia.org/wiki/Drake_equation

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 Post subject: Re: Are we alone in the universe?Posted: Fri, 30 Dec 2011 04:55:36 UTC
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As useless as vatican city!

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 Post subject: Re: Are we alone in the universe?Posted: Fri, 30 Dec 2011 07:38:35 UTC
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pickslides wrote:
Hi there, maybe a mathematical idea does exist

http://en.wikipedia.org/wiki/Drake_equation

Just because there is an equation doesn't make it mathematical. Consider and therefore God exists. It's gibberish, but it has an equation.

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 Post subject: Re: Are we alone in the universe?Posted: Sat, 31 Dec 2011 01:19:34 UTC
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The Drake equation is a meaningful attempt at getting a handle on this question. However, some terms are extremely difficult to estimate.

---------------------------------------------------------------------
N = the number of civilizations in our galaxy with which communication might be possible (= product of all the following);

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

The first three terms should be estimated reasonably well in the near future, based on the Kepler program.

The fourth term might be estimated by assuming that a large fraction of earth sized planets in the "Goldilocks" zone will develop life.

The last three are the big unknowns. If you take the earth as a typical case, life has existed for 3.5 million years, but we have been sending out radio signals for only a little over 100 years. Homo sapiens may be just a lucky accident.

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 Post subject: Re: Are we alone in the universe?Posted: Sat, 31 Dec 2011 02:12:38 UTC
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mathematic wrote:
The Drake equation is a meaningful attempt at getting a handle on this question. However, some terms are extremely difficult to estimate.

---------------------------------------------------------------------
N = the number of civilizations in our galaxy with which communication might be possible (= product of all the following);

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

The first three terms should be estimated reasonably well in the near future, based on the Kepler program.

The fourth term might be estimated by assuming that a large fraction of earth sized planets in the "Goldilocks" zone will develop life.

The last three are the big unknowns. If you take the earth as a typical case, life has existed for 3.5 million years, but we have been sending out radio signals for only a little over 100 years. Homo sapiens may be just a lucky accident.

What are you talking about? Life on Earth has existed for WAY more than 3.5 million years. Heck, it's a big part of popular culture that the last major meteor impact happened 65.5 million years ago, which killed the dinosaurs, and they were certainly alive. And all life is essentially a lucky accident. And in any case, we don't even really KNOW definitively that there are only 9 (or 8 if you don't like Pluto) planets in our own solar system, "good" estimates on a stellar scale are extremely dubious if you need accurate information to use the Drake equation, and regardless of the "intent" on getting a handle on ideas, it's not mathematical, it's just an attempt to use mathematics, which has some repute as the only exact science to give credence to the ideas of someone else. At its heart it's a philosophical question, and at best it's a question in astro-physics, but it is certainly not mathematical.

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 Post subject: Re: Are we alone in the universe?Posted: Sat, 31 Dec 2011 05:12:40 UTC
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mathematic wrote:
If you take the earth as a typical case, life has existed for 3.5 million years...

More like 3.5 billion years.

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 Post subject: Re: Are we alone in the universe?Posted: Sat, 31 Dec 2011 09:50:37 UTC
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Only a few thousand years per the bible;
whatever makes it appear longer than that has been planted by satan!

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 Post subject: Re: Are we alone in the universe?Posted: Sat, 31 Dec 2011 19:56:49 UTC
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outermeasure wrote:
mathematic wrote:
If you take the earth as a typical case, life has existed for 3.5 million years...

More like 3.5 billion years.

Only three orders of magnitude off.

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 Post subject: Re: Are we alone in the universe?Posted: Sun, 1 Jan 2012 00:38:43 UTC
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outermeasure wrote:
mathematic wrote:
If you take the earth as a typical case, life has existed for 3.5 million years...

More like 3.5 billion years.

You're right - I know it is 3.5 billion - I just got mixed up.

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 Post subject: The question is pointless...Posted: Wed, 4 Jan 2012 20:22:54 UTC
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Joined: Sat, 31 Oct 2009 20:14:21 UTC
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because how would we know there is other life in our universe?

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 Post subject: Re: The question is pointless...Posted: Wed, 4 Jan 2012 23:24:39 UTC
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math explorer wrote:
because how would we know there is other life in our universe?

The SETI project is trying to find out.

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