| Topic: |
Science > Physics |
| User: |
"dkomo" |
| Date: |
21 Aug 2006 10:27:55 AM |
| Object: |
There's life out there! |
How would one go about estimating the probability that life has
developed on a planet orbiting at least one star in the observable
universe? Amir Aczel in his book _Probability 1_ gives an example of
one such calculation.
He estimates the probability that *no* life comes about at a given star,
and then multiplies this probability by the number of stars in the
universe. This gives the probability that no life has formed anywhere
in the universe. Subtracting that probability from one gives the
probability that life has formed one or more times.
Here's an outline:
a = probability that a star has a planet = 0.5
b = probability if it has a planet that planet will be
in the habitable zone and can harbor life = 1/9
(using our solar system as an example)
c = probability that life will go ahead and develop on the planet =
one chance in a trillion
so p = a*b*c = 0.00000000000005 is the probability life will develop
around a given star
Next, there are 300 billion stars in our galaxy and 100 billion galaxies
in the observable universe (Aczel's numbers), so the number of stars is
N = 30,000,000,000,000,000,000,000,000
So the probability of *no* life forming anywhere is
(1 - p)^N = (0.99999999999995)^(30,000,000,000,000,000,000,000,000)
This is a probability that is indistinguishable from zero at any level
of decimal accuracy given by most computers or calculators.
Finally, the probability that life has formed at least once is 1 minus
the above probability, or almost identically 1.
Hence the name of the book: _Probability 1_ :-)
Viewing the above numbers, it's not hard to conclude that the universe
is probably *teeming* with life. Even decreasing p and N by several
orders of magnitude makes little difference to the conclusion.
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| User: "Brad Guth" |
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| Title: Re: There's life out there! |
23 Aug 2006 10:06:23 AM |
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So the probability of *no* life forming anywhere is
(1 - p)^N = (0.99999999999995)^(30,000,000,000,000,000,000,000,000)
This is a probability that is indistinguishable from zero at any level
of decimal accuracy given by most computers or calculators.
Finally, the probability that life has formed at least once is 1 minus
the above probability, or almost identically 1.
Hence the name of the book: _Probability 1_ :-)
Viewing the above numbers, it's not hard to conclude that the universe
is probably *teeming* with life. Even decreasing p and N by several
orders of magnitude makes little difference to the conclusion.
dkomo (aka "There's life out there!")
What ever you do, don't bother to inform our NASA or much less SETI,
whereas even if further reducing those numbers of viable stars (mostly
binaries) as hosting livable planets by another million to one is still
imposing a universe that's as you say "*teeming* with life".
Of course that life need not be the least bit human, nor having
originated upon any given planet or moon thereof (some moons may even be
larger than Earth and having a mother planet of Jupiter+ class which
gives off it's own thermal energy as well as a beneficial shield via
magnetosphere, to the point where a red dwarf or even a thermally less
than dead star may yet exist but is other than gravity of no further
need). Of course that only goes towards further improving the odds by
way of including other viable options for such other life, especially of
intelligent other life to exist/coexist. For that matter, a black hole
of a once upon a time massive star could host a few such substantial
planets of sufficient size and mass that would make for a perfectly
viable option of hosting life upon the moons thereof.
Remember that regardless of whatever big-bang or subsequent
little-bangs, that everything remains in orbit about something,
including our solar systems and those of every other solar system are in
fact by way of our mutual gravity in orbit about one another. Even our
Universe seems to represent itself as a roundish formation that's not
likely independent from any other universe.
Regardless of the point of any given origination or the unavoidable
galactic encounters ever since, there's no such thing as a free drifting
cluster, star, planet, moon or speck of dust. Independence is not a
viable option.
A planet of *teeming* life might not have any forms of intelligent
humanoids, just limited to smarter plants, insects, bugs and animals,
much like Earth was for the first of our planetology of life creative
billions of years. In fact, there's no good reason why a life *teeming*
planet need ever become polluted or otherwise devastated with
intelligent human life.
The very definition of intelligent other life may in fact have little
room within to cope with the absolute mess of disfunctional human life
that we're stuck with. Intelligent other life need not be limited to
the primitive technology of radio or microwaves, and/or having any need
or motivations as to being the least bit interested in whatever's right
next door.
To define upon which class of planets or moons are unlikely to host or
otherwise accommodate intelligent other life might only further help to
expand upon the possibilities of appreciating as to whatever applied
technology and/or of bio-engineered options have had to contribute,
towards making such other difficult/complex worlds or their moons as
into viable options of having been terraformed into sustaining other
life. In fact, intelligent creation of life itself seems a more likely
option than not (at least we humans have been intentionally and
unintentionally into doing that all the time).
Our perception as to what supposedly eliminates most other planets or
moons of hosting intelligent other life is badly infomercial and
otherwise social/political/religious skewed in order to suit the comfort
zone of our mainstream status quo, which by all means wants nothing to
do with even accepting unintelligent other life, including their
disregard upon much of the life that's sequestered here upon Earth. As
it turns out, I perceive that humanity thus far has not been a good
example of intelligent life, that is unless you consider arrogance,
greed, bigotry and insufferable intolerance as desirable qualities that
fits within your definition of whatever intelligent life is all about.
So all and all, my having expanded upon the odds of there being not only
other life to behold as being more than likely nearby and perhaps not
nearly as likely to being as incest mutated to the extent our complex
mass of humanity has demonstrated thus far, is simply imposing that it's
far more than remotely possible and perhaps even within our physical
reach.
Would yourself or others like further proof, or would just making do
with the regular laws of physics and of the best available science
suffice?
-
Brad Guth
--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG
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| User: "Brad Guth" |
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| Title: Re: There's life out there! |
24 Aug 2006 11:55:29 AM |
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That's rather interesting. You make an honest effort as to agree with
the intent of what the original author had to say, and further agree
with a number of those having constrictively contributed on the very
same set of scientific and intellectual tracks and lo and behold, the
topic instantly goes into hiding/stealth mode.
I suggest upon any number of viable alternatives that are within the
fullest agreement with what the intent of this topic and author had to
share, and right away we see the original author and of his/her
following is actually deathly afraid of their own shadows.
It's as though all of the sudden, the planet Venus or of anything else
that I might have to share becomes taboo/off-limits if not nondisclosure
worthy.
Am I that right?
-
Brad Guth
--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG
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| User: "=?UTF-8?Q?Jeff=E2=80=A6Relf?=" |
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| Title: Anything that consumes and is consumed is alive. |
21 Aug 2006 10:40:08 PM |
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Hi DKomo, As I just told T.J. deeper in this thread...
Most people are narrow-minded enough that they think " life " requires
the super narrow temperature range of liquid water;
e.g. Mars is too cold and Venus is too hot.
So Planck_Temperature ( 10 ^ 32 degrees Kelvin )
at the start of our observable universe was too _Way_ hot ( they assert ) and
the virtual vacuum ( i.e. absolute zero ) at the end will be _Way_ too cold,
....or so they claim, full of their pathetic hubris.
But I ask: How could this be ? how are we so damn lucky ?
Surely it's not luck, it's just a Human_Centric ( narrow ) definition of life.
Anything that consumes and is consumed is alive.
Life is like this:
Each is imprisoned in a virtual casino... the house always wins in the end.
Like you're both God _And_ Devil ( lets use the mnemonic " God_Devil " )
to the animals and plants you raise to feed yourself
( i.e. like you punish and reward them, to control them ),
you're God_Devil's tenant and God_Devil to your tenants.
Entropy is the top God_Devil because, like a lit match,
consumption ( i.e. dissipation, Gibbs_Free_Energy or entropy )
both creates and destroys all that ever was.
Although control is the goal, it's a mirage.
Time is pseudo-directional ( i.e. spatial )
because, like a dice toss is known to be pseudorandom ( i.e. causal ),
all randomness is pseudorandom.
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| User: "Brad Guth" |
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| Title: Re: There's life out there! |
23 Aug 2006 08:58:31 PM |
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In addition to accepting the intent of this nifty "There's life out
there!" topic by "dkomo", I also concur with the likes of "Golden
Helmet", "J. Horta" and "Jeff?Relf", that our limited/narrow notions of
a survivable environment shouldn't the least bit a factor as to
appreciating what other equally if not more so complex forms of life
could manage, and especially not as to excluding whatever's of
intelligent other life. However, in most instances the DNA lethal
spectrums of solar/cosmic radiation are of what's soon enough going to
represent a fairly complex evolutionary do or die trying sort of
ultimate quest for most any of our known terrestrial species, that which
we humans are in the minority as well as in the process of failing
rather badly at our evolutionary advancement progress (not only is our
global warming of mother nature doing us in, but we're still into
directly exterminating our own kind for domination sport and/or for
taking the other guy's energy), whereas eventually we may have to focus
upon adapting to having rad-hard DNA before it's too late. Therefore,
of other worlds or moons poorly if at all protected by a magnetosphere,
and/or via a somewhat less than substantial atmosphere, are going to
remain as doubtful environments for the sorts of complex DNA formulated
or implanted life that isn't already rad-hard to start with. Thereby of
other than whatever has been intelligently engineered to suit and/or
having somehow adapted to surviving underground or perhaps as under or
within whatever's salty ice is about all we're going to find within such
otherwise unprotected if not Mars like naked surface environments.
Too often the likes of our hit and run "CeeBee" and then as always "Bill
Snyder" are only here as for primarily for sharing in the fun and games
of life (if need be at the continued expense and demise of their own
kind), whereas such individuals seldom if ever contribute by way of
their actions. Therefore playing it safe and willing to jump the fence
at any sign of trouble is their failsafe form of keeping within their
status quo comfort zone. I'll take the honest likes of "tj Frazir" over
"CeeBee" or "Bill Snyder" any day of the week, whereas many of the
others that seem unable to constructively contribute to this topic are
not worth their salt, much less of their infomercial-science crapolla
that's continually emerging from within their intellectual status quo or
bust flatulence, whereas clearly these sorry individuals have no moral
or otherwise honest intentions of constructively contributing to
anything that rocks their status quo good ship LOLLIPOP, that more often
than not has been flying a Jewish flag.
At least the constructive nature of "dkomo" is being perfectly honest
and open mindset about the possibilities or rather the likely
probabilities that has to be the case on behalf of there being other
life. I'd say as a rare if not somewhat badly mutated species of this
universe, we humans simply are not alone, nor are we nearly enough
all-knowing.
I can assure "dkomo" and the other honestly open minded individuals that
there is other nearby intelligent life to be exploited, and of their
worlds and/or moon(s) to be pillaged and raped without a stitch of
remorse, just like we've exploited most every other less developed
nation of typically nice and survival worthy folks right here on Earth
(especially if they so happen to be sitting upon our oil or some other
valuable element), along with imposing our LLPOF acceptable form of
collateral damage and carnage of the innocent in order to prove that our
God is better than their's, and being of mostly white humans we're
somehow entitled to take the fullest advantage of and if need be
entitled to terminate those which fail to appreciate our point of view,
or even that of our perverted sense of humor. So why should our space
exploitations of other worlds and/or moons be any different?
I bet our resident LLPOF warlord(GW Bush) has so much Botoxin within his
butt-brain that he could even manage to keep a straight butt-crack while
telling us all about those ET WMD, and to think that most of these
Usenet borg like minions as being so entirely brown-nosed couldn't
possibly resist yet another opportunity of inflicting such widespread
collateral damage and carnage of the innocent.
Unfortunately, of those being of a narrow/naysay mindset is exactly why
we've been in such previous and existing fiascos (with no apparent end
in sight), whereas if you're one of those which can't honestly think
independently inside your box, then thinking outside is rather unlikely
if not entirely taboo/nondisclosure, and thereby pointless to argue with
and/or much less share and share alike upon anything that's the least
bit new and improved.
I believe it's specifically because of these pretentious/all-knowing
folks that can't accept nor much less allow others to hear the truth, as
being those which also can't accept the future unless it involves tonnes
of untaxable loot getting placed into their offshore banking accounts.
Therefore, pondering as to other life (intelligent or not) that's within
our neighborhood and perhaps even within our physical reach is rather
useless chat within this typically anti-think-tank of such a highly
bigoted and cult like revengeful Usenet from naysay hell.
Short of my having contributed the observationology of what's likely
existing/coexisting on Venus, and of eventually firing off my battery of
lose cannons and of pushing a few of those do-not-push buttons, whereas
I still don't have all the answers, nor have I the cloak and dagger
wherewithal as to enforcing much of anything, whereas saying "I told you
so" is often as good as it gets.
At times my having survived the gauntlet of their GOOGLE/Usenet funded
and approved PC spermware/fuckware is also about as good as it gets,
although I'm fairly certain MI/NSA and otherwise as having been directly
contributed and/or orchestrated from the many invested friends of their
puppet NASA are also in on the wag-thy-dog worth of accomplishing
similar damage-control. At this point there's far more of those
mainstream status quo butts to cover than you can imagine, and those
butts have their extended families of sisters/brothers/nieces/nephews
and perhaps by now generations of their first and second cousins to
support.
Would you folks like to know what else sucks and blows, if not stinks to
high heaven? Or, would you like to seriously ponder the
why-the-heck-not on behalf of other intelligent life as having been
existing/coexisting on Venus?
-
Brad Guth
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Posted via Mailgate.ORG Server - http://www.Mailgate.ORG
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| User: "Brad Guth" |
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| Title: Re: There's life out there! |
24 Aug 2006 03:41:19 PM |
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Unlike walking on the moon, at least I can prove it within the regular
laws of physics, as well as I can otherwise prove with the best
available science, that there has been and may yet be other intelligent
life existing/coexisting on Venus.
Would any of you folks like to argure and/or constructively contribute
as to why the hell not? or is that by itself asking too much?
-
"If you're not looking for the truth, you will not find it."
-Brad Guth
"To believe with certainty we must begin with doubting."
-Stanislaus I
"The real voyage of discovery consists not in seeking new landscapes,
but having new eyes."
-Marcel Proust
"Truth is given, not to be contemplated, but to be done. Life is an
action, not a thought."
-F.W. Robertson
~
Even grumpy old Kurt Vonnegut would have to agree that; WAR is WAR,
thus "in war there are no rules" - In fact, war has been the very reason
why honest folks are having to deal with the likes of others that
haven't been playing by whatever the supposed rules, such as our
resident LLPOF warlord(GW Bush) having invented WMD seems to come to
mind.
Life upon Venus, a township w/Bridge & ET/UFO Park-n-Ride Tarmac:
http://guthvenus.tripod.com/gv-town.htm
The Russian/China LSE-CM/ISS (Lunar Space Elevator)
http://guthvenus.tripod.com/lunar-space-elevator.htm
Venus ETs, plus the updated sub-topics; Brad Guth / GASA-IEIS
http://guthvenus.tripod.com/gv-topics.htm
--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG
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| User: "tj Frazir" |
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| Title: Re: There's life out there! evolution is nonexclusive |
24 Aug 2006 11:28:34 PM |
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Wer not the only humans and the humans here evolved on evry contenet .
out of 150 pices of humans on earth about 5 remain .
500 illion years ago some place else some dickheads on another planet
talked about this.
ONLINE !!
The visible univese we see is a grain of sand on a large beach.
Saying we are allone is like saying this is the only planet in the
universe where there is a trillion trillion planets .
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| User: "Brad Guth" |
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| Title: Re: There's life out there! evolution is nonexclusive |
27 Aug 2006 11:15:58 AM |
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"tj Frazir" <GravityPhysics@webtv.net> wrote in message
news:15968-44EE7C72-48@storefull-3212.bay.webtv.net
Wer not the only humans and the humans here evolved on evry contenet .
out of 150 pices of humans on earth about 5 remain .
500 illion years ago some place else some dickheads on another planet
talked about this.
ONLINE !!
The visible univese we see is a grain of sand on a large beach.
Saying we are allone is like saying this is the only planet in the
universe where there is a trillion trillion planets .
tj Frazir,
I totally agree with all of that, and then some.
Like here on Earth where certain islands have been teaming with complex
plant and animal life, yet never once having evolved with an original
species of human as to contaminate, pillage and rape everything to
death, whereas I tend to believe there are a few such other worlds
(possibly nearby) without human contamination.
I also believe that we're within a 105,000 (+/- 5,000) year orbital
cycle with our parent Sirius star/solar system. I say this because of
the available science and also because the regular laws of physics is
what makes it impossible to not be the case.
Gravity sucks, as in regardless of whatever big-bang or little-bang
happenstance, everything is unavoidably in orbit around something. We
are not biologically, intellectually nor otherwise physically alone,
just badly snookered and otherwise having been dumbfounded to death for
most of our pathetically bigoted lives.
Why the heck is SETI looking only for the remainders of other arrogant,
greedy, dumbfounded and terribly bigoted humans (apparently looking for
Jewish ETs none the less)?
By the time we've detected their multi-thousand light year message, arnt
those folks rather dead, as may will be the whole incest of humanity
upon this magnetosphere failing Earth within the next thousand years.
So what's the difference?
I have a few serious physics and science related questions about Venus,
of which I'll pay the likes of yourself big-time loot if you'll help my
research along, or otherwise merely contribute as to kicking a few of
those mainstream butts that are in a bad way in need of their getting
kicked to hell.
-
Brad Guth
--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG
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| User: "" |
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| Title: Re: There's life out there! |
21 Aug 2006 11:48:18 AM |
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In article <Gamdnc6e1eqfTHTZnZ2dnUVZ_oudnZ2d@comcast.com>, dkomo <dkomo871@comcast.net> writes:
How would one go about estimating the probability that life has
developed on a planet orbiting at least one star in the observable
universe? Amir Aczel in his book _Probability 1_ gives an example of
one such calculation.
He estimates the probability that *no* life comes about at a given star,
and then multiplies this probability by the number of stars in the
universe. This gives the probability that no life has formed anywhere
in the universe. Subtracting that probability from one gives the
probability that life has formed one or more times.
Here's an outline:
a = probability that a star has a planet = 0.5
b = probability if it has a planet that planet will be
in the habitable zone and can harbor life = 1/9
(using our solar system as an example)
c = probability that life will go ahead and develop on the planet =
one chance in a trillion
so p = a*b*c = 0.00000000000005 is the probability life will develop
around a given star
Next, there are 300 billion stars in our galaxy and 100 billion galaxies
in the observable universe (Aczel's numbers), so the number of stars is
N = 30,000,000,000,000,000,000,000,000
So the probability of *no* life forming anywhere is
(1 - p)^N = (0.99999999999995)^(30,000,000,000,000,000,000,000,000)
This is a probability that is indistinguishable from zero at any level
of decimal accuracy given by most computers or calculators.
Finally, the probability that life has formed at least once is 1 minus
the above probability, or almost identically 1.
Hence the name of the book: _Probability 1_ :-)
Viewing the above numbers, it's not hard to conclude that the universe
is probably *teeming* with life. Even decreasing p and N by several
orders of magnitude makes little difference to the conclusion.
A classic example of a totally nonsensical calculation. The problem
is with the assumptions. (a) may be reasonable (based on the systems
we observed so far). (b), well, maybe, drawing conclusions from a
sample of 1 (solar system) is a no-no in statistics. But, let it
pass. The real problem is with (c) which includes a number pulled out
of the author's *****. Why one in a trillion? Why not one in a
thousand, or 1/10^100. Or anything. The "one in a trillion" is based
on nothing more than "lets pick some small number". But the number
may be much larger (while still remaining small) or way, way smaller.
And, yes, it can be so small that (1-p)^N is nearly indistinguishable
from 1, thus 1 minus this probability is almost identically zero. I'm
not saying that this is indeed the case, only that we do not have, at
present, the information to say anything sensible about the magnitude
in (c) and we should be honest about it. Deciding what answer one
wants and fabricating numbers to support it is a very bad practice.
Mati Meron | "When you argue with a fool,
meron@cars.uchicago.edu | chances are he is doing just the same"
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| User: "dkomo" |
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| Title: Re: There's life out there! |
21 Aug 2006 12:51:54 PM |
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wrote:
In article <Gamdnc6e1eqfTHTZnZ2dnUVZ_oudnZ2d@comcast.com>, dkomo <dkomo871@comcast.net> writes:
How would one go about estimating the probability that life has
developed on a planet orbiting at least one star in the observable
universe? Amir Aczel in his book _Probability 1_ gives an example of
one such calculation.
He estimates the probability that *no* life comes about at a given star,
and then multiplies this probability by the number of stars in the
universe. This gives the probability that no life has formed anywhere
in the universe. Subtracting that probability from one gives the
probability that life has formed one or more times.
Here's an outline:
a = probability that a star has a planet = 0.5
b = probability if it has a planet that planet will be
in the habitable zone and can harbor life = 1/9
(using our solar system as an example)
c = probability that life will go ahead and develop on the planet =
one chance in a trillion
so p = a*b*c = 0.00000000000005 is the probability life will develop
around a given star
Next, there are 300 billion stars in our galaxy and 100 billion galaxies
in the observable universe (Aczel's numbers), so the number of stars is
N = 30,000,000,000,000,000,000,000,000
So the probability of *no* life forming anywhere is
(1 - p)^N = (0.99999999999995)^(30,000,000,000,000,000,000,000,000)
This is a probability that is indistinguishable from zero at any level
of decimal accuracy given by most computers or calculators.
Finally, the probability that life has formed at least once is 1 minus
the above probability, or almost identically 1.
Hence the name of the book: _Probability 1_ :-)
Viewing the above numbers, it's not hard to conclude that the universe
is probably *teeming* with life. Even decreasing p and N by several
orders of magnitude makes little difference to the conclusion.
A classic example of a totally nonsensical calculation. The problem
is with the assumptions. (a) may be reasonable (based on the systems
we observed so far). (b), well, maybe, drawing conclusions from a
sample of 1 (solar system) is a no-no in statistics. But, let it
pass. The real problem is with (c) which includes a number pulled out
of the author's *****. Why one in a trillion? Why not one in a
thousand, or 1/10^100. Or anything. The "one in a trillion" is based
on nothing more than "lets pick some small number". But the number
may be much larger (while still remaining small) or way, way smaller.
And, yes, it can be so small that (1-p)^N is nearly indistinguishable
from 1, thus 1 minus this probability is almost identically zero. I'm
not saying that this is indeed the case, only that we do not have, at
present, the information to say anything sensible about the magnitude
in (c) and we should be honest about it. Deciding what answer one
wants and fabricating numbers to support it is a very bad practice.
Isn't there some information in the fact that life did form on planet
earth that allows us to refine the estimate of p above? I think that
Aczel's estimate of p is too low. As you know, for a normal distribution,
mu = N * p where mu is the expected number of successes
= expected number of times life developed
For our galaxy, N = 300 billion stars, p = 5e-14 from above so
mu = 3e11 * 5e-15 = 1.5e-3
which seems much too low.
If instead we *assume* mu is at least 1 (life did develop on earth), we
get a p = mu / N = 1 / 3e11 = 3.33e-12
What do you think?
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| User: "" |
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| Title: Re: There's life out there! |
21 Aug 2006 04:00:02 PM |
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In article <DtCdncNUwaJcb3TZnZ2dnUVZ_rudnZ2d@comcast.com>, dkomo <dkomo871@comcast.net> writes:
mmeron@cars3.uchicago.edu wrote:
In article <Gamdnc6e1eqfTHTZnZ2dnUVZ_oudnZ2d@comcast.com>, dkomo <dkomo871@comcast.net> writes:
How would one go about estimating the probability that life has
developed on a planet orbiting at least one star in the observable
universe? Amir Aczel in his book _Probability 1_ gives an example of
one such calculation.
He estimates the probability that *no* life comes about at a given star,
and then multiplies this probability by the number of stars in the
universe. This gives the probability that no life has formed anywhere
in the universe. Subtracting that probability from one gives the
probability that life has formed one or more times.
Here's an outline:
a = probability that a star has a planet = 0.5
b = probability if it has a planet that planet will be
in the habitable zone and can harbor life = 1/9
(using our solar system as an example)
c = probability that life will go ahead and develop on the planet =
one chance in a trillion
so p = a*b*c = 0.00000000000005 is the probability life will develop
around a given star
Next, there are 300 billion stars in our galaxy and 100 billion galaxies
in the observable universe (Aczel's numbers), so the number of stars is
N = 30,000,000,000,000,000,000,000,000
So the probability of *no* life forming anywhere is
(1 - p)^N = (0.99999999999995)^(30,000,000,000,000,000,000,000,000)
This is a probability that is indistinguishable from zero at any level
of decimal accuracy given by most computers or calculators.
Finally, the probability that life has formed at least once is 1 minus
the above probability, or almost identically 1.
Hence the name of the book: _Probability 1_ :-)
Viewing the above numbers, it's not hard to conclude that the universe
is probably *teeming* with life. Even decreasing p and N by several
orders of magnitude makes little difference to the conclusion.
A classic example of a totally nonsensical calculation. The problem
is with the assumptions. (a) may be reasonable (based on the systems
we observed so far). (b), well, maybe, drawing conclusions from a
sample of 1 (solar system) is a no-no in statistics. But, let it
pass. The real problem is with (c) which includes a number pulled out
of the author's *****. Why one in a trillion? Why not one in a
thousand, or 1/10^100. Or anything. The "one in a trillion" is based
on nothing more than "lets pick some small number". But the number
may be much larger (while still remaining small) or way, way smaller.
And, yes, it can be so small that (1-p)^N is nearly indistinguishable
from 1, thus 1 minus this probability is almost identically zero. I'm
not saying that this is indeed the case, only that we do not have, at
present, the information to say anything sensible about the magnitude
in (c) and we should be honest about it. Deciding what answer one
wants and fabricating numbers to support it is a very bad practice.
Isn't there some information in the fact that life did form on planet
earth that allows us to refine the estimate of p above?
No, there really isn't.
I think that
Aczel's estimate of p is too low. As you know, for a normal distribution,
mu = N * p where mu is the expected number of successes
= expected number of times life developed
For our galaxy, N = 300 billion stars, p = 5e-14 from above so
mu = 3e11 * 5e-15 = 1.5e-3
which seems much too low.
If instead we *assume* mu is at least 1 (life did develop on earth), we
get a p = mu / N = 1 / 3e11 = 3.33e-12
What do you think?
All you know is that p is not zero. Beyond this, you can't say. Why
would you take our galaxy as a baseline, for the number of tries,
instead of, say, the local group, or even the whole observable
universe. Or, to the other extreme, just the sphere of stars within,
say, 100 l.y. from Sol. So you can get nearly any number, depending
on what N you pick.
More important, though, your statistics is extremely poor, just a
single case. Now, true, when you get k successes out of n tries, your
estimate for probability of success is k/n. but this estimate (which,
after all, results from fallible measurement) has a statistical
uncertainty which is about sqrt(k)/n. So, where k = 1, the
uncertainty of the result is as large as the result itself and you
really cannot say anything.
Note, again, I'm not trying to claim that Aczel's estimate is
unreasonably high, nor that it is unreasonably low. I'm just saying
that he has no basis for any estimate and that the scientifically
honest thing to do when the information available is not sufficient
for a reasonable answer is to say just this, instead of inventing
numbers.
Mati Meron | "When you argue with a fool,
meron@cars.uchicago.edu | chances are he is doing just the same"
.
|
|
|
| User: "Peter Webb" |
|
| Title: Re: There's life out there! |
22 Aug 2006 08:36:52 AM |
|
|
<mmeron@cars3.uchicago.edu> wrote in message
news:m9pGg.11$25.137@news.uchicago.edu...
In article <DtCdncNUwaJcb3TZnZ2dnUVZ_rudnZ2d@comcast.com>, dkomo
<dkomo871@comcast.net> writes:
mmeron@cars3.uchicago.edu wrote:
In article <Gamdnc6e1eqfTHTZnZ2dnUVZ_oudnZ2d@comcast.com>, dkomo
<dkomo871@comcast.net> writes:
How would one go about estimating the probability that life has
developed on a planet orbiting at least one star in the observable
universe? Amir Aczel in his book _Probability 1_ gives an example of
one such calculation.
He estimates the probability that *no* life comes about at a given star,
and then multiplies this probability by the number of stars in the
universe. This gives the probability that no life has formed anywhere
in the universe. Subtracting that probability from one gives the
probability that life has formed one or more times.
Here's an outline:
a = probability that a star has a planet = 0.5
b = probability if it has a planet that planet will be
in the habitable zone and can harbor life = 1/9
(using our solar system as an example)
c = probability that life will go ahead and develop on the planet =
one chance in a trillion
so p = a*b*c = 0.00000000000005 is the probability life will develop
around a given star
Next, there are 300 billion stars in our galaxy and 100 billion galaxies
in the observable universe (Aczel's numbers), so the number of stars is
N = 30,000,000,000,000,000,000,000,000
So the probability of *no* life forming anywhere is
(1 - p)^N = (0.99999999999995)^(30,000,000,000,000,000,000,000,000)
This is a probability that is indistinguishable from zero at any level
of decimal accuracy given by most computers or calculators.
Finally, the probability that life has formed at least once is 1 minus
the above probability, or almost identically 1.
Hence the name of the book: _Probability 1_ :-)
Viewing the above numbers, it's not hard to conclude that the universe
is probably *teeming* with life. Even decreasing p and N by several
orders of magnitude makes little difference to the conclusion.
A classic example of a totally nonsensical calculation. The problem
is with the assumptions. (a) may be reasonable (based on the systems
we observed so far). (b), well, maybe, drawing conclusions from a
sample of 1 (solar system) is a no-no in statistics. But, let it
pass. The real problem is with (c) which includes a number pulled out
of the author's *****. Why one in a trillion? Why not one in a
thousand, or 1/10^100. Or anything. The "one in a trillion" is based
on nothing more than "lets pick some small number". But the number
may be much larger (while still remaining small) or way, way smaller.
And, yes, it can be so small that (1-p)^N is nearly indistinguishable
from 1, thus 1 minus this probability is almost identically zero. I'm
not saying that this is indeed the case, only that we do not have, at
present, the information to say anything sensible about the magnitude
in (c) and we should be honest about it. Deciding what answer one
wants and fabricating numbers to support it is a very bad practice.
Isn't there some information in the fact that life did form on planet
earth that allows us to refine the estimate of p above?
No, there really isn't.
I think that
Aczel's estimate of p is too low. As you know, for a normal distribution,
mu = N * p where mu is the expected number of successes
= expected number of times life developed
For our galaxy, N = 300 billion stars, p = 5e-14 from above so
mu = 3e11 * 5e-15 = 1.5e-3
which seems much too low.
If instead we *assume* mu is at least 1 (life did develop on earth), we
get a p = mu / N = 1 / 3e11 = 3.33e-12
What do you think?
All you know is that p is not zero. Beyond this, you can't say. Why
would you take our galaxy as a baseline, for the number of tries,
instead of, say, the local group, or even the whole observable
universe. Or, to the other extreme, just the sphere of stars within,
say, 100 l.y. from Sol. So you can get nearly any number, depending
on what N you pick.
More important, though, your statistics is extremely poor, just a
single case. Now, true, when you get k successes out of n tries, your
estimate for probability of success is k/n. but this estimate (which,
after all, results from fallible measurement) has a statistical
uncertainty which is about sqrt(k)/n. So, where k = 1, the
uncertainty of the result is as large as the result itself and you
really cannot say anything.
Note, again, I'm not trying to claim that Aczel's estimate is
unreasonably high, nor that it is unreasonably low. I'm just saying
that he has no basis for any estimate and that the scientifically
honest thing to do when the information available is not sufficient
for a reasonable answer is to say just this, instead of inventing
numbers.
Mati Meron | "When you argue with a fool,
meron@cars.uchicago.edu | chances are he is doing just the same"
I'm not a statistician, but I disagree that life on earth is a single trial,
and nothing can be inferred from it.
Here's a thought experiment. I have 1000 boxes, and I say to you, these
boxes may all be empty, all have a prize in them, or anything in between.
You can open as many boxes as you like until you find a prize.
You start opening boxes at random, and the second box you open has a prize.
From this, you would infer that there is probably more than one box with a
prize in it.
Life on earth is a bit like that, but instead of boxes we have one million
year periods of the earth's history. Life developed very early on earth;
soon after it cooled and stabilised. It was in one of the very first boxes
that was opened.
If the earth was (say) 10 billion years old, and life developed only 1
million years ago, then I would infer that life developing was a
comparitively rare event (it took 10,000 periods of 1 million years before
it appeared). That is not the case. Life appeared almost immediately; like
finding a prize in the first or second box that you open, it suggests that
it is a comparatively likely event.
.
|
|
|
| User: "Shawn" |
|
| Title: Re: There's life out there! |
23 Aug 2006 07:19:25 PM |
|
|
Good. When this human "civilization" finally blows it's self to smithereens
& destroys all life
with it, the universe will become totally quiet once again.
.
|
|
|
|
| User: "" |
|
| Title: Re: There's life out there! |
22 Aug 2006 10:40:50 AM |
|
|
In article <44eb086c$0$11971$afc38c87@news.optusnet.com.au>, "Peter Webb" <webbfamily-diespamdie@optusnet.com.au> writes:
<mmeron@cars3.uchicago.edu> wrote in message
news:m9pGg.11$25.137@news.uchicago.edu...
In article <DtCdncNUwaJcb3TZnZ2dnUVZ_rudnZ2d@comcast.com>, dkomo
<dkomo871@comcast.net> writes:
mmeron@cars3.uchicago.edu wrote:
In article <Gamdnc6e1eqfTHTZnZ2dnUVZ_oudnZ2d@comcast.com>, dkomo
<dkomo871@comcast.net> writes:
How would one go about estimating the probability that life has
developed on a planet orbiting at least one star in the observable
universe? Amir Aczel in his book _Probability 1_ gives an example of
one such calculation.
He estimates the probability that *no* life comes about at a given star,
and then multiplies this probability by the number of stars in the
universe. This gives the probability that no life has formed anywhere
in the universe. Subtracting that probability from one gives the
probability that life has formed one or more times.
Here's an outline:
a = probability that a star has a planet = 0.5
b = probability if it has a planet that planet will be
in the habitable zone and can harbor life = 1/9
(using our solar system as an example)
c = probability that life will go ahead and develop on the planet =
one chance in a trillion
so p = a*b*c = 0.00000000000005 is the probability life will develop
around a given star
Next, there are 300 billion stars in our galaxy and 100 billion galaxies
in the observable universe (Aczel's numbers), so the number of stars is
N = 30,000,000,000,000,000,000,000,000
So the probability of *no* life forming anywhere is
(1 - p)^N = (0.99999999999995)^(30,000,000,000,000,000,000,000,000)
This is a probability that is indistinguishable from zero at any level
of decimal accuracy given by most computers or calculators.
Finally, the probability that life has formed at least once is 1 minus
the above probability, or almost identically 1.
Hence the name of the book: _Probability 1_ :-)
Viewing the above numbers, it's not hard to conclude that the universe
is probably *teeming* with life. Even decreasing p and N by several
orders of magnitude makes little difference to the conclusion.
A classic example of a totally nonsensical calculation. The problem
is with the assumptions. (a) may be reasonable (based on the systems
we observed so far). (b), well, maybe, drawing conclusions from a
sample of 1 (solar system) is a no-no in statistics. But, let it
pass. The real problem is with (c) which includes a number pulled out
of the author's *****. Why one in a trillion? Why not one in a
thousand, or 1/10^100. Or anything. The "one in a trillion" is based
on nothing more than "lets pick some small number". But the number
may be much larger (while still remaining small) or way, way smaller.
And, yes, it can be so small that (1-p)^N is nearly indistinguishable
from 1, thus 1 minus this probability is almost identically zero. I'm
not saying that this is indeed the case, only that we do not have, at
present, the information to say anything sensible about the magnitude
in (c) and we should be honest about it. Deciding what answer one
wants and fabricating numbers to support it is a very bad practice.
Isn't there some information in the fact that life did form on planet
earth that allows us to refine the estimate of p above?
No, there really isn't.
I think that
Aczel's estimate of p is too low. As you know, for a normal distribution,
mu = N * p where mu is the expected number of successes
= expected number of times life developed
For our galaxy, N = 300 billion stars, p = 5e-14 from above so
mu = 3e11 * 5e-15 = 1.5e-3
which seems much too low.
If instead we *assume* mu is at least 1 (life did develop on earth), we
get a p = mu / N = 1 / 3e11 = 3.33e-12
What do you think?
All you know is that p is not zero. Beyond this, you can't say. Why
would you take our galaxy as a baseline, for the number of tries,
instead of, say, the local group, or even the whole observable
universe. Or, to the other extreme, just the sphere of stars within,
say, 100 l.y. from Sol. So you can get nearly any number, depending
on what N you pick.
More important, though, your statistics is extremely poor, just a
single case. Now, true, when you get k successes out of n tries, your
estimate for probability of success is k/n. but this estimate (which,
after all, results from fallible measurement) has a statistical
uncertainty which is about sqrt(k)/n. So, where k = 1, the
uncertainty of the result is as large as the result itself and you
really cannot say anything.
Note, again, I'm not trying to claim that Aczel's estimate is
unreasonably high, nor that it is unreasonably low. I'm just saying
that he has no basis for any estimate and that the scientifically
honest thing to do when the information available is not sufficient
for a reasonable answer is to say just this, instead of inventing
numbers.
Mati Meron | "When you argue with a fool,
meron@cars.uchicago.edu | chances are he is doing just the same"
I'm not a statistician, but I disagree that life on earth is a single trial,
and nothing can be inferred from it.
Here's a thought experiment. I have 1000 boxes, and I say to you, these
boxes may all be empty, all have a prize in them, or anything in between.
You can open as many boxes as you like until you find a prize.
You start opening boxes at random, and the second box you open has a prize.
From this, you would infer that there is probably more than one box with a
prize in it.
Nah, I wouldn't. I would just infer that there may be more than one
box.
Life on earth is a bit like that, but instead of boxes we have one million
year periods of the earth's history.
Ahh. Why "one million year periods"? Why not "3428891 years
periods"? Or one day periods or 12.4 seconds periods? Your choice of
"box" is completely arbitrary and any results thus derived are meaningless.
Life developed very early on earth; soon after it cooled and stabilised.
It was in one of the very first boxes that was opened.
Having no other Earth to compare we're in no position to judge how
likely this event was.
If the earth was (say) 10 billion years old, and life developed only 1
million years ago, then I would infer that life developing was a
comparitively rare event (it took 10,000 periods of 1 million years before
it appeared). That is not the case. Life appeared almost immediately; like
finding a prize in the first or second box that you open, it suggests that
it is a comparatively likely event.
It may be likely or it may be not, we simply do not have enough
information to quantify it and, in absence of such information,
drawing numerical conclusions as Aczel did is nonsense.
Mati Meron | "When you argue with a fool,
meron@cars.uchicago.edu | chances are he is doing just the same"
.
|
|
|
| User: "Timo A. Nieminen" |
|
| Title: Re: There's life out there! |
22 Aug 2006 03:01:13 PM |
|
|
On Tue, 22 Aug 2006, wrote:
"Peter Webb" <webbfamily-diespamdie@optusnet.com.au> writes:
If the earth was (say) 10 billion years old, and life developed only 1
million years ago, then I would infer that life developing was a
comparitively rare event (it took 10,000 periods of 1 million years before
it appeared). That is not the case. Life appeared almost immediately; like
finding a prize in the first or second box that you open, it suggests that
it is a comparatively likely event.
It may be likely or it may be not, we simply do not have enough
information to quantify it and, in absence of such information,
drawing numerical conclusions as Aczel did is nonsense.
In particular, one needs to consider that our presence here is not
independent of life having developed on Earth. A sample size of one leads
to perilous statistics (although the sample size is actually larger that
one - we have yet to unambiguously detect life or past life on the Moon,
the Sun, Venus, etc, possible astro-microbes notwithstanding). But the
bias due to the dependence of our presence here on the development of life
on Earth is overwhelming.
Perhaps eukaryoticity (is this a real word?) is a stupendously unlikely
event, but bacteria are universally ubiquitous. How can we even guess,
without a larger sample? "Student"'s papers are still a classic in
small-sample statistice - you can't extrapolate from a sample of one.
--
Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/
E-prints: http://eprint.uq.edu.au/view/person/Nieminen,_Timo_A..html
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html
.
|
|
|
| User: "" |
|
| Title: Re: There's life out there! |
22 Aug 2006 11:01:36 PM |
|
|
In article <Pine.WNT.4.64.0608230552000.1380@serene.st>, "Timo A. Nieminen" <timo@physics.uq.edu.au> writes:
On Tue, 22 Aug 2006, wrote:
"Peter Webb" <webbfamily-diespamdie@optusnet.com.au> writes:
If the earth was (say) 10 billion years old, and life developed only 1
million years ago, then I would infer that life developing was a
comparitively rare event (it took 10,000 periods of 1 million years before
it appeared). That is not the case. Life appeared almost immediately; like
finding a prize in the first or second box that you open, it suggests that
it is a comparatively likely event.
It may be likely or it may be not, we simply do not have enough
information to quantify it and, in absence of such information,
drawing numerical conclusions as Aczel did is nonsense.
In particular, one needs to consider that our presence here is not
independent of life having developed on Earth. A sample size of one leads
to perilous statistics (although the sample size is actually larger that
one - we have yet to unambiguously detect life or past life on the Moon,
the Sun, Venus, etc, possible astro-microbes notwithstanding). But the
bias due to the dependence of our presence here on the development of life
on Earth is overwhelming.
Aye, indeed. The ultimate case of sampling bias.
Perhaps eukaryoticity (is this a real word?) is a stupendously unlikely
event, but bacteria are universally ubiquitous. How can we even guess,
without a larger sample? "Student"'s papers are still a classic in
small-sample statistice - you can't extrapolate from a sample of one.
Yet, there are always people who'll try:-)
Mati Meron | "When you argue with a fool,
meron@cars.uchicago.edu | chances are he is doing just the same"
.
|
|
|
| User: "Ken Muldrew" |
|
| Title: Re: There's life out there! |
23 Aug 2006 12:47:33 PM |
|
|
wrote:
In article <Pine.WNT.4.64.0608230552000.1380@serene.st>, "Timo A. Nieminen" <timo@physics.uq.edu.au> writes:
How can we even guess,
without a larger sample? "Student"'s papers are still a classic in
small-sample statistice - you can't extrapolate from a sample of one.
Yet, there are always people who'll try:-)
And even among those who have learned this first, elementary lesson,
there are some who will rave about the outstanding linear fit they got
to two data points...and proceed to extrapolate. The bane of
pattern-matching based intelligence.
Ken Muldrew
kmuldrezw@ucalgazry.ca
(remove all letters after y in the alphabet)
.
|
|
|
|
| User: "" |
|
| Title: Re: There's life out there! |
23 Aug 2006 01:13:33 PM |
|
|
In article <44ec944a.500897374@news.ucalgary.ca>, (Ken Muldrew) writes:
mmeron@cars3.uchicago.edu wrote:
In article <Pine.WNT.4.64.0608230552000.1380@serene.st>, "Timo A. Nieminen" <timo@physics.uq.edu.au> writes:
How can we even guess,
without a larger sample? "Student"'s papers are still a classic in
small-sample statistice - you can't extrapolate from a sample of one.
Yet, there are always people who'll try:-)
And even among those who have learned this first, elementary lesson,
there are some who will rave about the outstanding linear fit they got
to two data points...and proceed to extrapolate.
Oh, yeah. Talking about combining offenses.
The bane of pattern-matching based intelligence.
Yes, exactly. A pattern will be found, whether it exists or it
doesn't.
Mati Meron | "When you argue with a fool,
meron@cars.uchicago.edu | chances are he is doing just the same"
.
|
|
|
|
|
|
|
| User: "Forgetful Goldfish" |
|
| Title: Re: There's life out there! |
22 Aug 2006 09:37:47 AM |
|
|
Peter Webb wrote:
<mmeron@cars3.uchicago.edu> wrote in message
news:m9pGg.11$25.137@news.uchicago.edu...
In article <DtCdncNUwaJcb3TZnZ2dnUVZ_rudnZ2d@comcast.com>, dkomo
<dkomo871@comcast.net> writes:
mmeron@cars3.uchicago.edu wrote:
In article <Gamdnc6e1eqfTHTZnZ2dnUVZ_oudnZ2d@comcast.com>, dkomo
<dkomo871@comcast.net> writes:
How would one go about estimating the probability that life has
developed on a planet orbiting at least one star in the observable
universe? Amir Aczel in his book _Probability 1_ gives an example of
one such calculation.
He estimates the probability that *no* life comes about at a given star,
and then multiplies this probability by the number of stars in the
universe. This gives the probability that no life has formed anywhere
in the universe. Subtracting that probability from one gives the
probability that life has formed one or more times.
Here's an outline:
a = probability that a star has a planet = 0.5
b = probability if it has a planet that planet will be
in the habitable zone and can harbor life = 1/9
(using our solar system as an example)
c = probability that life will go ahead and develop on the planet =
one chance in a trillion
so p = a*b*c = 0.00000000000005 is the probability life will develop
around a given star
Next, there are 300 billion stars in our galaxy and 100 billion galaxies
in the observable universe (Aczel's numbers), so the number of stars is
N = 30,000,000,000,000,000,000,000,000
So the probability of *no* life forming anywhere is
(1 - p)^N = (0.99999999999995)^(30,000,000,000,000,000,000,000,000)
This is a probability that is indistinguishable from zero at any level
of decimal accuracy given by most computers or calculators.
Finally, the probability that life has formed at least once is 1 minus
the above probability, or almost identically 1.
Hence the name of the book: _Probability 1_ :-)
Viewing the above numbers, it's not hard to conclude that the universe
is probably *teeming* with life. Even decreasing p and N by several
orders of magnitude makes little difference to the conclusion.
A classic example of a totally nonsensical calculation. The problem
is with the assumptions. (a) may be reasonable (based on the systems
we observed so far). (b), well, maybe, drawing conclusions from a
sample of 1 (solar system) is a no-no in statistics. But, let it
pass. The real problem is with (c) which includes a number pulled out
of the author's *****. Why one in a trillion? Why not one in a
thousand, or 1/10^100. Or anything. The "one in a trillion" is based
on nothing more than "lets pick some small number". But the number
may be much larger (while still remaining small) or way, way smaller.
And, yes, it can be so small that (1-p)^N is nearly indistinguishable
from 1, thus 1 minus this probability is almost identically zero. I'm
not saying that this is indeed the case, only that we do not have, at
present, the information to say anything sensible about the magnitude
in (c) and we should be honest about it. Deciding what answer one
wants and fabricating numbers to support it is a very bad practice.
Isn't there some information in the fact that life did form on planet
earth that allows us to refine the estimate of p above?
No, there really isn't.
I think that
Aczel's estimate of p is too low. As you know, for a normal distribution,
mu = N * p where mu is the expected number of successes
= expected number of times life developed
For our galaxy, N = 300 billion stars, p = 5e-14 from above so
mu = 3e11 * 5e-15 = 1.5e-3
which seems much too low.
If instead we *assume* mu is at least 1 (life did develop on earth), we
get a p = mu / N = 1 / 3e11 = 3.33e-12
What do you think?
All you know is that p is not zero. Beyond this, you can't say. Why
would you take our galaxy as a baseline, for the number of tries,
instead of, say, the local group, or even the whole observable
universe. Or, to the other extreme, just the sphere of stars within,
say, 100 l.y. from Sol. So you can get nearly any number, depending
on what N you pick.
More important, though, your statistics is extremely poor, just a
single case. Now, true, when you get k successes out of n tries, your
estimate for probability of success is k/n. but this estimate (which,
after all, results from fallible measurement) has a statistical
uncertainty which is about sqrt(k)/n. So, where k = 1, the
uncertainty of the result is as large as the result itself and you
really cannot say anything.
Note, again, I'm not trying to claim that Aczel's estimate is
unreasonably high, nor that it is unreasonably low. I'm just saying
that he has no basis for any estimate and that the scientifically
honest thing to do when the information available is not sufficient
for a reasonable answer is to say just this, instead of inventing
numbers.
Mati Meron | "When you argue with a fool,
meron@cars.uchicago.edu | chances are he is doing just the same"
I'm not a statistician, but I disagree that life on earth is a single trial,
and nothing can be inferred from it.
Here's a thought experiment. I have 1000 boxes, and I say to you, these
boxes may all be empty, all have a prize in them, or anything in between.
You can open as many boxes as you like until you find a prize.
You start opening boxes at random, and the second box you open has a prize.
From this, you would infer that there is probably more than one box with a
prize in it.
Life on earth is a bit like that, but instead of boxes we have one million
year periods of the earth's history. Life developed very early on earth;
soon after it cooled and stabilised. It was in one of the very first boxes
that was opened.
If the earth was (say) 10 billion years old, and life developed only 1
million years ago, then I would infer that life developing was a
comparitively rare event (it took 10,000 periods of 1 million years before
it appeared). That is not the case. Life appeared almost immediately; like
finding a prize in the first or second box that you open, it suggests that
it is a comparatively likely event.
As far as I understand most of the planets we have found so far don't
have curricular orbits making it extremely unlikely that life will
evolve. Also none of the other terrestrial planets in our solar system
have large satellites that stop the earth from flipping on its axis, I
am led to believe ( that is, the moon stops the earth filliping on its
axis I am pretty sure we have large satellite though some people on
this news group would probably dispute even this). How probable is a
large satellite and circular orbit? But the main problem is as I see
it, if there is life out there why has it not come to see us? Even a
modestly slow space travelling alien would have be here by now. Are
they just shy, I doubt it.
.
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| User: "CeeBee ceebee@novalidmail" |
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| Title: Re: There's life out there! |
23 Aug 2006 07:34:08 PM |
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"Forgetful Goldfish" <kieranwyse@hotmail.com> wrote in sci.astro:
But the main problem is as I see
it, if there is life out there why has it not come to see us? Even a
modestly slow space travelling alien would have be here by now. Are
they just shy, I doubt it.
It seems to be _our_ problem, not "theirs". First of all, why would
"aliens" want to go out and find us because we want to go out and want to
find others?
Second, it's always clear that how high the estimates are, they're still
estimates, the universe is incredibly large and the distances are enormous.
Generations grown up with Star Trek and Star Wars seem to have a believe
that the universe is our backyard, and that eventually technology will let
us hop around in a few hours from star to star.
--
CeeBee
*** Democracy is not a spectator sport ***
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| User: "dkomo" |
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| Title: Re: There's life out there! |
23 Aug 2006 10:01:31 AM |
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Forgetful Goldfish wrote:
Peter Webb wrote:
<mmeron@cars3.uchicago.edu> wrote in message
news:m9pGg.11$25.137@news.uchicago.edu...
In article <DtCdncNUwaJcb3TZnZ2dnUVZ_rudnZ2d@comcast.com>, dkomo
<dkomo871@comcast.net> writes:
mmeron@cars3.uchicago.edu wrote:
In article <Gamdnc6e1eqfTHTZnZ2dnUVZ_oudnZ2d@comcast.com>, dkomo
<dkomo871@comcast.net> writes:
How would one go about estimating the probability that life has
developed on a planet orbiting at least one star in the observable
universe? Amir Aczel in his book _Probability 1_ gives an example of
one such calculation.
He estimates the probability that *no* life comes about at a given star,
and then multiplies this probability by the number of stars in the
universe. This gives the probability that no life has formed anywhere
in the universe. Subtracting that probability from one gives the
probability that life has formed one or more times.
Here's an outline:
a = probability that a star has a planet = 0.5
b = probability if it has a planet that planet will be
in the habitable zone and can harbor life = 1/9
(using our solar system as an example)
c = probability that life will go ahead and develop on the planet =
one chance in a trillion
so p = a*b*c = 0.00000000000005 is the probability life will develop
around a given star
Next, there are 300 billion stars in our galaxy and 100 billion galaxies
in the observable universe (Aczel's numbers), so the number of stars is
N = 30,000,000,000,000,000,000,000,000
So the probability of *no* life forming anywhere is
(1 - p)^N = (0.99999999999995)^(30,000,000,000,000,000,000,000,000)
This is a probability that is indistinguishable from zero at any level
of decimal accuracy given by most computers or calculators.
Finally, the probability that life has formed at least once is 1 minus
the above probability, or almost identically 1.
Hence the name of the book: _Probability 1_ :-)
Viewing the above numbers, it's not hard to conclude that the universe
is probably *teeming* with life. Even decreasing p and N by several
orders of magnitude makes little difference to the conclusion.
A classic example of a totally nonsensical calculation. The problem
is with the assumptions. (a) may be reasonable (based on the systems
we observed so far). (b), well, maybe, drawing conclusions from a
sample of 1 (solar system) is a no-no in statistics. But, let it
pass. The real problem is with (c) which includes a number pulled out
of the author's *****. Why one in a trillion? Why not one in a
thousand, or 1/10^100. Or anything. The "one in a trillion" is based
on nothing more than "lets pick some small number". But the number
may be much larger (while still remaining small) or way, way smaller.
And, yes, it can be so small that (1-p)^N is nearly indistinguishable
from 1, thus 1 minus this probability is almost identically zero. I'm
not saying that this is indeed the case, only that we do not have, at
present, the information to say anything sensible about the magnitude
in (c) and we should be honest about it. Deciding what answer one
wants and fabricating numbers to support it is a very bad practice.
Isn't there some information in the fact that life did form on planet
earth that allows us to refine the estimate of p above?
No, there really isn't.
I think that
Aczel's estimate of p is too low. As you know, for a normal distribution,
mu = N * p where mu is the expected number of successes
= expected number of times life developed
For our galaxy, N = 300 billion stars, p = 5e-14 from above so
mu = 3e11 * 5e-15 = 1.5e-3
which seems much too low.
If instead we *assume* mu is at least 1 (life did develop on earth), we
get a p = mu / N = 1 / 3e11 = 3.33e-12
What do you think?
All you know is that p is not zero. Beyond this, you can't say. Why
would you take our galaxy as a baseline, for the number of tries,
instead of, say, the local group, or even the whole observable
universe. Or, to the other extreme, just the sphere of stars within,
say, 100 l.y. from Sol. So you can get nearly any number, depending
on what N you pick.
More important, though, your statistics is extremely poor, just a
single case. Now, true, when you get k successes out of n tries, your
estimate for probability of success is k/n. but this estimate (which,
after all, results from fallible measurement) has a statistical
uncertainty which is about sqrt(k)/n. So, where k = 1, the
uncertainty of the result is as large as the result itself and you
really cannot say anything.
Note, again, I'm not trying to claim that Aczel's estimate is
unreasonably high, nor that it is unreasonably low. I'm just saying
that he has no basis for any estimate and that the scientifically
honest thing to do when the information available is not sufficient
for a reasonable answer is to say just this, instead of inventing
numbers.
Mati Meron | "When you argue with a fool,
meron@cars.uchicago.edu | chances are he is doing just the same"
I'm not a statistician, but I disagree that life on earth is a single trial,
and nothing can be inferred from it.
Here's a thought experiment. I have 1000 boxes, and I say to you, these
boxes may all be empty, all have a prize in them, or anything in between.
You can open as many boxes as you like until you find a prize.
You start opening boxes at random, and the second box you open has a prize.
From this, you would infer that there is probably more than one box with a
prize in it.
Life on earth is a bit like that, but instead of boxes we have one million
year periods of the earth's history. Life developed very early on earth;
soon after it cooled and stabilised. It was in one of the very first boxes
that was opened.
If the earth was (say) 10 billion years old, and life developed only 1
million years ago, then I would infer that life developing was a
comparitively rare event (it took 10,000 periods of 1 million years before
it appeared). That is not the case. Life appeared almost immediately; like
finding a prize in the first or second box that you open, it suggests that
it is a comparatively likely event.
As far as I understand most of the planets we have found so far don't
have curricular orbits making it extremely unlikely that life will
evolve. Also none of the other terrestrial planets in our solar system
have large satellites that stop the earth from flipping on its axis, I
am led to believe ( that is, the moon stops the earth filliping on its
axis I am pretty sure we have large satellite though some people on
this news group would probably dispute even this). How probable is a
large satellite and circular orbit? But the main problem is as I see
it, if there is life out there why has it not come to see us? Even a
modestly slow space travelling alien would have be here by now. Are
they just shy, I doubt it.
Why haven't they found *us*? Let's see, our galaxy has about 300
billion stars. The latest estimate I've seen is that 90% of them could
have planets. That's 270 billion planets (assuming only one planet per
star system) to search in order to find intelligent species. That's a
tall order even for a very advanced alien civilization. And our own
planet has been lit up at night only since about the late 1800's when
gas lightning in the streets of cities became commonplace, while
widespread use of radio waves didn't come along until the 1920's.
.
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| User: "Brad Guth" |
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| Title: Re: There's life out there! |
27 Aug 2006 11:31:55 AM |
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"dkomo" <dkomo871@comcast.net> wrote in message
news:oKGdnQNwoolF8HHZnZ2dnUVZ_v-dnZ2d@comcast.com
Why haven't they found *us*? Let's see, our galaxy has about 300
billion stars. The latest estimate I've seen is that 90% of them could
have planets. That's 270 billion planets (assuming only one planet per
star system) to search in order to find intelligent species. That's a
tall order even for a very advanced alien civilization. And our own
planet has been lit up at night only since about the late 1800's when
gas lightning in the streets of cities became commonplace, while
widespread use of radio waves didn't come along until the 1920's.
We're also still using microwaves and/or of wussy radar signals that are
terribly interstellar inefficient, and even at that there's been no
beacon efforts honestly applied towards the most nearby of viable other
star/solar systems.
On our global warming Earth is where human greed, arrogance and bigotry
is policy, thus being status quo snookered and/or dumbfounded is also
required.
Most of our talents and resources have been devoted to exterminating our
own kind over the limited energy resources of this magnetosphere failing
planet.
Like here on Earth where certain islands have been teaming with complex
plant and animal life, yet never once having evolved with an original
species of human as to contaminate, pillage and rape everything to
death, whereas I tend to believe there are a few such other worlds
(possibly nearby) without human contamination.
I also believe that we're within a 105,000 (+/- 5,000) year orbital
cycle with our parent Sirius star/solar system. I have to say this
because of the available science and also because the regular laws of
physics is what makes it impossible to not be the case.
Gravity sucks, as in regardless of whatever big-bang or little-bang
happenstance, everything is unavoidably in orbit around something. We
are not biologically, intellectually nor otherwise physically alone,
just badly snookered and otherwise having been dumbfounded to death for
most of our pathetically bigoted lives.
Why the heck is SETI looking only for the remainders of other arrogant,
greedy, dumbfounded and terribly bigoted humans (apparently looking for
Jewish ETs none the less)?
By the time we've detected their multi-thousand light year message, arnt
those folks rather dead, as may will be the whole incest of humanity
upon this magnetosphere failing Earth within the next thousand years.
So what's the difference?
I have a few perfectly serious physics and hard-science related
questions about Venus, of which I'll gladly share and share alike by
paying the likes of yourself big-time loot if you'll help my research
along, or otherwise merely contribute as to kicking a few of those
mainstream butts that are in a bad way in need of their getting kicked
to hell.
-
Brad Guth
--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG
.
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| User: "" |
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| Title: Re: There's life out there! |
23 Aug 2006 08:09:27 AM |
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Forgetful Goldfish wrote:
Peter Webb wrote:
<mmeron@cars3.uchicago.edu> wrote in message
news:m9pGg.11$25.137@news.uchicago.edu...
In article <DtCdncNUwaJcb3TZnZ2dnUVZ_rudnZ2d@comcast.com>, dkomo
<dkomo871@comcast.net> writes:
mmeron@cars3.uchicago.edu wrote:
In article <Gamdnc6e1eqfTHTZnZ2dnUVZ_oudnZ2d@comcast.com>, dkomo
<dkomo871@comcast.net> writes:
How would one go about estimating the probability that life has
developed on a planet orbiting at least one star in the observable
universe? Amir Aczel in his book _Probability 1_ gives an example of
one such calculation.
He estimates the probability that *no* life comes about at a given star,
and then multiplies this probability by the number of stars in the
universe. This gives the probability that no life has formed anywhere
in the universe. Subtracting that probability from one gives the
probability that life has formed one or more times.
Here's an outline:
a = probability that a star has a planet = 0.5
b = probability if it has a planet that planet will be
in the habitable zone and can harbor life = 1/9
(using our solar system as an example)
c = probability that life will go ahead and develop on the planet =
one chance in a trillion
so p = a*b*c = 0.00000000000005 is the probability life will develop
around a given star
Next, there are 300 billion stars in our galaxy and 100 billion galaxies
in the observable universe (Aczel's numbers), so the number of stars is
N = 30,000,000,000,000,000,000,000,000
So the probability of *no* life forming anywhere is
(1 - p)^N = (0.99999999999995)^(30,000,000,000,000,000,000,000,000)
This is a probability that is indistinguishable from zero at any level
of decimal accuracy given by most computers or calculators.
Finally, the probability that life has formed at least once is 1 minus
the above probability, or almost identically 1.
Hence the name of the book: _Probability 1_ :-)
Viewing the above numbers, it's not hard to conclude that the universe
is probably *teeming* with life. Even decreasing p and N by several
orders of magnitude makes little difference to the conclusion.
A classic example of a totally nonsensical calculation. The problem
is with the assumptions. (a) may be reasonable (based on the systems
we observed so far). (b), well, maybe, drawing conclusions from a
sample of 1 (solar system) is a no-no in statistics. But, let it
pass. The real problem is with (c) which includes a number pulled out
of the author's *****. Why one in a trillion? Why not one in a
thousand, or 1/10^100. Or anything. The "one in a trillion" is based
on nothing more than "lets pick some small number". But the number
may be much larger (while still remaining small) or way, way smaller.
And, yes, it can be so small that (1-p)^N is nearly indistinguishable
from 1, thus 1 minus this probability is almost identically zero. I'm
not saying that this is indeed the case, only that we do not have, at
present, the information to say anything sensible about the magnitude
in (c) and we should be honest about it. Deciding what answer one
wants and fabricating numbers to support it is a very bad practice.
Isn't there some information in the fact that life did form on planet
earth that allows us to refine the estimate of p above?
No, there really isn't.
I think that
Aczel's estimate of p is too low. As you know, for a normal distribution,
mu = N * p where mu is the expected number of successes
= expected number of times life developed
For our galaxy, N = 300 billion stars, p = 5e-14 from above so
mu = 3e11 * 5e-15 = 1.5e-3
which seems much too low.
If instead we *assume* mu is at least 1 (life did develop on earth), we
get a p = mu / N = 1 / 3e11 = 3.33e-12
What do you think?
All you know is that p is not zero. Beyond this, you can't say. Why
would you take our galaxy as a baseline, for the number of tries,
instead of, say, the local group, or even the whole observable
universe. Or, to the other extreme, just the sphere of stars within,
say, 100 l.y. from Sol. So you can get nearly any number, depending
on what N you pick.
More important, though, your statistics is extremely poor, just a
single case. Now, true, when you get k successes out of n tries, your
estimate for probability of success is k/n. but this estimate (which,
after all, results from fallible measurement) has a statistical
uncertainty which is about sqrt(k)/n. So, where k = 1, the
uncertainty of the result is as large as the result itself and you
really cannot say anything.
Note, again, I'm not trying to claim that Aczel's estimate is
unreasonably high, nor that it is unreasonably low. I'm just saying
that he has no basis for any estimate and that the scientifically
honest thing to do when the information available is not sufficient
for a reasonable answer is to say just this, instead of inventing
numbers.
Mati Meron | "When you argue with a fool,
meron@cars.uchicago.edu | chances are he is doing just the same"
I'm not a statistician, but I disagree that life on earth is a single trial,
and nothing can be inferred from it.
Here's a thought experiment. I have 1000 boxes, and I say to you, these
boxes may all be empty, all have a prize in them, or anything in between.
You can open as many boxes as you like until you find a prize.
You start opening boxes at random, and the second box you open has a prize.
From this, you would infer that there is probably more than one box with a
prize in it.
Life on earth is a bit like that, but instead of boxes we have one million
year periods of the earth's history. Life developed very early on earth;
soon after it cooled and stabilised. It was in one of the very first boxes
that was opened.
If the earth was (say) 10 billion years old, and life developed only 1
million years ago, then I would infer that life developing was a
comparitively rare event (it took 10,000 periods of 1 million years before
it appeared). That is not the case. Life appeared almost immediately; like
finding a prize in the first or second box that you open, it suggests that
it is a comparatively likely event.
As far as I understand most of the planets we have found so far don't
have curricular orbits making it extremely unlikely that life will
evolve. Also none of the other terrestrial planets in our solar system
have large satellites that stop the earth from flipping on its axis, I
am led to believe ( that is, the moon stops the earth filliping on its
axis I am pretty sure we have large satellite though some people on
this news group would probably dispute even this). How probable is a
large satellite and circular orbit? But the main problem is as I see
it, if there is life out there why has it not come to see us? Even a
modestly slow space travelling alien would have be here by now. Are
they just shy, I doubt it.
What would incite advanced aliens to spend time and efforts to
contact less developed civilizations?
Marcel Luttgens
.
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| User: "J. Horta" |
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| Title: Re: There's life out there! |
21 Aug 2006 07:40:29 PM |
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On Mon, 21 Aug 2006 09:27:55 -0600, dkomo wrote:
How would one go about estimating the probability that life has
developed on a planet orbiting at least one star in the observable
universe? Amir Aczel in his book _Probability 1_ gives an example of
one such calculation.
He estimates the probability that *no* life comes about at a given star,
and then multiplies this probability by the number of stars in the
universe. This gives the probability that no life has formed anywhere
in the universe. Subtracting that probability from one gives the
probability that life has formed one or more times.
Here's an outline:
a = probability that a star has a planet = 0.5
b = probability if it has a planet that planet will be
in the habitable zone and can harbor life = 1/9
(using our solar system as an example)
c = probability that life will go ahead and develop on the planet =
one chance in a trillion
so p = a*b*c = 0.00000000000005 is the probability life will develop
around a given star
Next, there are 300 billion stars in our galaxy and 100 billion galaxies
in the observable universe (Aczel's numbers), so the number of stars is
N = 30,000,000,000,000,000,000,000,000
So the probability of *no* life forming anywhere is
(1 - p)^N = (0.99999999999995)^(30,000,000,000,000,000,000,000,000)
This is a probability that is indistinguishable from zero at any level
of decimal accuracy given by most computers or calculators.
Finally, the probability that life has formed at least once is 1 minus
the above probability, or almost identically 1.
Hence the name of the book: _Probability 1_ :-)
Viewing the above numbers, it's not hard to conclude that the universe
is probably *teeming* with life. Even decreasing p and N by several
orders of magnitude makes little difference to the conclusion.
--dkomo@cris.com
Most likely life is a complex chemical reaction with a very slow time
constant. It's as likely as forming water from hydrogen and
oxygen given the proper conditions and no more (or less) random. The
chances of an earth-like planet not producing life in 3 or 4 billion
years is 0.
.
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| User: "Jan Panteltje" |
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| Title: Re: There's life out there! |
21 Aug 2006 11:00:11 AM |
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On a sunny day (Mon, 21 Aug 2006 09:27:55 -0600) it happened dkomo
<dkomo871@comcast.net> wrote in
<Gamdnc6e1eqfTHTZnZ2dnUVZ_oudnZ2d@comcast.com>:
How would one go about estimating the probability that life has
developed on a planet orbiting at least one star in the observable
universe?
100%, we are here.
.
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