Anyone believe in Aliens? in The AnswerBank: Science

This is the basis for the Drake Equation

http://www.msnbc.com/modules/drake/default.asp

i think the generally perceived theorem is that the odds of it not having happened anywhere are ermm...astronomical. no punin tend ed.

Clanad

There are, currently, 165 characteristics identified for life to exist on earth. These are being added to almost daily. Each is has been shown to be necessary and the odds of these occurring simultaneosly anywhere else has been estimated to be 1 chance in 10 to the 182nd... None of the "planets" discovered thus far display even a few of these requirements...

Loosehead

There are definately aliens and we will almost certainly never encounter them because of the distances involved. So any aliens you do encounter are the product of whatever drugs you are on at the time!

jake-the-peg

Clannad - are you not confusing this with the so called "tuning of the cosmological constant".

This affects the expansionary phase of the early univers which humans and aliens would equally be exposed to and therefore would have no effect on the probability of alien life evolving.

Although the development of life from basic inorganic chemistry remains one of the great unknowns the most notable fact is that life started so rapidly after the earth stabilised that the processes involved cannot be that unlikely.

Clanad

No confusion, jake. Examples of the fine tuning you reference include but aren't limited to:

Strong nuclear force constant
Weak nuclear force constant
Gravitational force constant
Electromagnetic force constant
Ratio of electromagnetic force constant to gravitational force constant
Ratio of proton to electron mass, etc.

However the characteristics necessary for like of any kind, to which I refer include:

Local abundance and distribution of dark matter, decay rates of different exotic mass particles, galaxy cluster size, galaxy location, star distance from closest spiral arm, number of stars in system, star age, star�s carbon to oxygen ratio, planetary distance from star, axis tilt of planet, mass and distance of moon, oceans-to-continents ratio, position & mass of Jupiter relative to Earth, carbon dioxide level in atmosphere, zinc quantity in crust, and regularity of cometary infall, to name but a few. I can understand your interpretation of the likelyhood for the genesis of life elsewhere. However, there is, as you know, a deafining sound of silence as to proof.

I find it highly ironic that the current movement towards the theory of intelligent design comes from within the scientific community, however...

-- answer removed --

slimfandango

Clanad, he's right, you've got your wires crossed there. In any given universe the chances of any life like ours (I mean even slightly like ours, not occupying the 8th dimension) is given by the list you provide, along with some other factors. However, given that we do in fact inhabit this type of universe, the chances of there then being other intelligent life even a little bit like ours is extremely extremely high. For this you need to take into account the number of stars, the likelihood of them having planets, planets in the right place etc etc. Basically based on this probability, to suggest that there are not intelligent alien civilizaitons, or have not been, is really absurd. If I play the national lottery every week for the next year, the chances of me winning every week are much higher than the chances of there not being alien life.

Second Point. Please explain your leap from universe which supports life like ourselves, thanks to fine tuning of ecological variables, and there being intelligent design behind it.

slimfandango

And by the way, the constants your first mention (weak force, gravitational etc) are the same throughout the universe. It is strangely homologous.

And since you mention carbon/oxygen etc, this is being overanthropocentric, there is no reason why there could not be types of "intelligent life" based on types of chemistry other than the carbon based one to which we are acquainted.

-- answer removed --

newtron

Also Clanad, can you provide references please. Thanks.

Clanad

For newtron:

(This will take a couple of postings, please be patient)

First, the list of 165 currently identified requirements:

local abundance and distribution of dark matter 0.1
relative abundances of different exotic mass particles 0.1
decay rates of different exotic mass particles 0.1
galaxy cluster size 0.1
galaxy cluster location 0.1
galaxy size 0.1
galaxy type 0.1
galaxy mass distribution 0.2
galaxy location 0.1
variability of local dwarf galaxy absorption rate 0.1
quantity of galactic dust 0.1
star location relative to galactic center 0.2
star distance from corotation circle of galaxy 0.005
star distance from closest spiral arm 0.1
z-axis extremes of star�s orbit 0.02
proximity of solar nebula to a type I supernova eruption 0.01
timing of solar nebula formation relative to type I supernova eruption 0.01
proximity of solar nebula to a type II supernova eruption 0.01

Clanad

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timing of solar nebula formation relative to type II supernova eruption 0.01
timing of hypernovae eruptions 0.2
number of hypernovae eruptions 0.1
flux of cosmic ray protons 0.1
variability of cosmic ray proton flux 0.1
number of stars in birthing cluster 0.01
star formation history in parent star vicinity 0.1
birth date of the star-planetary system 0.01
number of stars in system 0.7
number and timing of close encounters by nearby stars 0.01
proximity of close stellar encounters 0.1
masses of close stellar encounters 0.1
star age 0.4
star metallicity 0.05
ratio of 40K, 235,238U, 232Th to iron in star-planetary system 0.02
star orbital eccentricity 0.1
star mass 0.001
star luminosity change relative to speciation types & rates 0.00001
star color 0.4
star magnetic field 0.1
star magnetic field variability 0.1
stellar wind strength and variability 0.1
short period variation in parent star diameter 0.1
star�s carbon to oxygen ratio 0.01
star�s space velocity relative to Local Standard of Rest 0.05
star�s short term luminosity variability 0.05
star�s long term luminosity variability 0.05
amplitude and duration of star spot cycle 0.1
number & timing of solar system encounters with interstellar gas clouds 0.1
galactic tidal forces on planetary system 0.2
H3+ production 0.1
supernovae rates & locations 0.01
white dwarf binary types, rates, & locations 0.01
structure of comet cloud surrounding planetary system 0.3
planetary distance from star

Clanad

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inclination of planetary orbit 0.5
axis tilt of planet 0.3
rate of change of axial tilt 0.01
period and size of axis tilt variation 0.1
planetary rotation period 0.1
rate of change in planetary rotation period 0.05
planetary revolution period 0.2
planetary orbit eccentricity 0.3
rate of change of planetary orbital eccentricity 0.1
rate of change of planetary inclination 0.5
period and size of eccentricity variation 0.1
period and size of inclination variation 0.1
number of moons 0.2
mass and distance of moon 0.01
surface gravity (escape velocity) 0.001
tidal force from sun and moon 0.1
magnetic field 0.01
rate of change & character of change in magnetic field 0.1
albedo (planet reflectivity) 0.1
density 0.1
reducing strength of planet�s primordial mantle 0.3
thickness of crust 0.01
timing of birth of continent formation 0.1
oceans-to-continents ratio 0.2
rate of change in oceans to continents ratio 0.1
global distribution of continents 0.3
frequency, timing, & extent of ice ages 0.1
frequency, timing, & extent of global snowball events 0.1
asteroidal & cometary collision rate 0.1
change in asteroidal & cometary collision rates 0.1
rate of change in asteroidal & cometary collision rates 0.1
mass of body colliding with primordial Earth 0.002
timing of body colliding with primordial Earth 0.05
location of body�s collision with primordial Earth 0.05
position & mass of Jupiter relative to Earth 0.01
major planet eccentricities 0.1
major planet orbital instabilities 0.05
drift and rate of drift in major planet distances 0.05
number & distribution of planets 0.01
distance of gas giant planets from mean motion resonances 0.02
orbital separation distances among inner planets 0.01
mass of Neptune 0.1
total mass of Kuiper Belt asteroids

Clanad

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inclination of planetary orbit 0.5
axis tilt of planet 0.3
rate of change of axial tilt 0.01
period and size of axis tilt variation 0.1
planetary rotation period 0.1
rate of change in planetary rotation period 0.05
planetary revolution period 0.2
planetary orbit eccentricity 0.3
rate of change of planetary orbital eccentricity 0.1
rate of change of planetary inclination 0.5
period and size of eccentricity variation 0.1
period and size of inclination variation 0.1
number of moons 0.2
mass and distance of moon 0.01
surface gravity (escape velocity) 0.001
tidal force from sun and moon 0.1
magnetic field 0.01
rate of change & character of change in magnetic field 0.1
albedo (planet reflectivity) 0.1
density 0.1
reducing strength of planet�s primordial mantle 0.3
thickness of crust 0.01
timing of birth of continent formation 0.1
oceans-to-continents ratio 0.2
rate of change in oceans to continents ratio 0.1
global distribution of continents 0.3
frequency, timing, & extent of ice ages 0.1
frequency, timing, & extent of global snowball events 0.1
asteroidal & cometary collision rate 0.1
change in asteroidal & cometary collision rates 0.1
rate of change in asteroidal & cometary collision rates 0.1
mass of body colliding with primordial Earth 0.002
timing of body colliding with primordial Earth 0.05
location of body�s collision with primordial Earth 0.05
position & mass of Jupiter relative to Earth 0.01
major planet eccentricities 0.1
major planet orbital instabilities 0.05
drift and rate of drift in major planet distances 0.05
number & distribution of planets 0.01
distance of gas giant planets from mean motion resonances 0.02
orbital separation distances among inner planets 0.01
mass of Neptune 0.1
total mass of Kuiper Belt asteroids

Clanad

And now for citations:

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Anyone believe in Aliens?

Answers