Fine-Tuned Earth Part II: Comparing to Drake's Equation

 Did God fine-tune the Earth for life as we know it?

In my previous post on "Was the Earth Fine Tuned For Life?" I posted an equation for estimating the probability of another planet anywhere in the universe having life similar to earth's. The value that I calculated for that occurrence was approximately ONE occurrence in over a QUADRILLION. A commenter responded that I should compare my equation to Drake's Equation, formed in 1961 to determine how many planets we should detect in our galaxy with which we could communicate. I used the probability function for multiple events, each having a probability value, (estimated), and computing the overall probability that all events would occur at once on a given planet.

The values I gave for individual events which I consider critical for life on earth as we know it, are below:

SIZE AND GRAVITY: .4 or 4 out of 10,WATER: .1, ATMOSPHERIC CONSTITUTION: .01, OXYGEN RICH: .01,  RARE EARTHS MINERALS.1, THE SUN: .3, DISTANCE FROM THE SUN:  .2, RADIOACTIVITY: .5, DISTANCE AND PLACEMENT FROM THE GALACTIC CENTER: .5, THE OZONE LAYER: .1, VOLCANIC ACTIVITY: .3, EARTH'S  MAGNETIC FIELD: .2, SEASONS: .2, THE CREATION OF THE MOON: .0001.

Explanations for each event are contained in the previous post, "Was The Earth Fine-Tuned For Life?".

The function itself is:

 P = p1 x p2 x p3 x p4 ... where P is the overall probability, and p1,p1, etc are individual probabilities.

 Drake's equation was formed in much the same way, using the same probability function, but was for the express purpose of presenting it at a meeting at Green Bank Radio Observatory, in W.Va. in 1961, to allow the members to be able to determine the number of possible planets in our galaxy alone that we might expect to detect via radio communications techniques.

The major difference between Drakes equation and mine is that I compute the probability of life, and he calculates the NUMBER of planets (in our galaxy) we could possibly communicate with. The similarities are that that we both use the same probability function, and he estimates these values the same way that I do. We both give 2 as the maximum number of planets to expect around a typical star that would possibly have the requisite conditions that can support life but he gives the odds of life on these planets as 100%, which I think is ridiculous. He assumes that life will develop everywhere that conditions are right, when the only example we have to compare with is our own earth.

This factor alone makes his number of possible planets extraordinarily high at 10 out of 6 billion in the Milky Way galaxy, as estimated by Hubble analysts.

Another similarity is that he estimates the possibility of a star as having planets as .5 where I give an estimate at .3. Research since his equation came out has proven the number to be lower than his estimate. Later research results have caused most scientists to believe that his individual estimates of all events were high. My estimates are conservative, and more in line with current thinking.

If you reduce the factor L in his equation, which is the length of time he estimates we will exist to attempt communication, the number of planets, N, in Drake's equation comes WAY down, but he is calculating a different outcome to mine, in the number N of planets that will be produced in 10,000 years that can bear life. I believe he is also overestimating the length of time even our own civilization will be trying to communicate, given the troubling conditions on our planet at present, and the possibility of annihilation by nuclear war.

I see Drake's method as not being vastly different, or any more precise than my 'guesstimate' for finding probability. In fact, in light of recent findings, his values are actually LESS precise than mine. He uses the same probability function and the same method of estimating the odds of certain terms. I do disagree with him that 100% of all planets with certain conditions will develop life and that every star that has planets will have at least two such planets. That is an outrageous assumption given the unique requirements that we now know of for life, and given that our own sun, an average star, has only one, and is the only one we have to make a comparison with.

It was pointed out in the previous post that there was some inter-relatedness among my variables in my equation, which I admit to, but, as in the case of the tilt of the earth related to creation of the moon, and the Ozone layer related to having oxygen and an atmosphere, I accounted for that in the estimation of the variables. Ozone separately should be a very rare occurrence compared to oxygen, but I gave it  a .2 value instead of a .001,(the higher the value, the less influence on the outcome), because part of that occurrence is accounted for in the value given for having an oxygen rich atmosphere, given that not all oxygen-rich atmospheres will produce an ozone layer..

The following description of Drake's Equation and analysis is from Wikopedia:

I draw attention to the last paragraph, a modern assessment of the values used by Drake, which dispute those original values and agree more with my own values.

"  Drake's Equation is given as: N=R* x fp x ne x fl x fi x fc x L

R* is the average rate of star formation per year in our galaxy

fp is the fraction of those stars that have planets

ne is the average number of planets that can potentially support life per star that has planets

fℓ is the fraction of the above that actually go on to develop life at some point

fi is the fraction of the above that actually go on to develop intelligent life

fc is the fraction of civilizations that develop a technology that releases detectable signs of their existence into space

L is the length of time such civilizations release detectable signals into space.[2].

Historical estimates of the parameters

Considerable disagreement on the values of most of these parameters exists, but the values used by Drake and his colleagues in 1961 were:

R* = 10/year (10 stars formed per year, on the average over the life of the galaxy)
fp = 0.5 (half of all stars formed will have planets)
ne = 2 (stars with planets will have 2 planets capable of supporting life)
fl = 1 (100% of these planets will develop life)
fi = 0.01 (1% of which will be intelligent life)
fc = 0.01 (1% of which will be able to communicate)
L = 10,000 years (which will last 10,000 years).

Drake's values give N = 10 × 0.5 × 2 × 1 × 0.01 × 0.01 × 10,000 = 10.

The value of R* is determined from considerable astronomical data, and is the least disputed term of the equation; fp is less certain, but is still much firmer than the values following. Confidence in ne was once higher, but the discovery of numerous gas giants in close orbit with their stars has introduced doubt that life-supporting planets commonly survive the creation of their stellar systems. In addition, most stars in our galaxy are red dwarfs, which flare violently, mostly in X-rays-a property not conducive to life as we know it (simulations also suggest that these bursts erode planetary atmospheres). The possibility of life on moons of gas giants (such as Jupiter's moon Europa, or Saturn's moon Titan) adds further uncertainty to this figure.

Geological evidence from the Earth suggests that fl may be very high;(emphasis mine) life on Earth appears to have begun around the same time as favorable conditions arose, suggesting that abiogenesis may be relatively common once conditions are right. However, this evidence only looks at the Earth (a single model planet), and contains anthropic bias, as the planet of study was not chosen randomly, but by the living organisms that already inhabit it (ourselves). Also countering this argument is that there is no evidence for abiogenesis occurring more than once on the Earth-that is, all terrestrial life stems from a common origin. If abiogenesis were more common it would be speculated to have occurred more than once on the Earth.(emphasis mine). In addition, from a classical hypothesis testing standpoint, there are zero degrees of freedom, permitting no valid estimates to be made". Reprinted from Wikopedia.

Given the intervening evidence from when Drake's Equation was first published and the present, I believe my method of finding the probability of other life in the universe similar to the earth's, while not a precise value, and was not intended to be, is more accurate and up to date.

We really should appreciate more, the 'garden place' in the universe, that God has given us,