In the long history of looking for life elsewhere in the cosmos, one of the exciting discoveries has been learning the things a planet needs to support life. In 1961, American astronomer Frank Drake proposed what is called the Drake Equation. He was looking for a way to calculate the number of inhabited planets in our galaxy with which communication might be possible. Drake’s equation lists seven parameters that would determine the answer to that question. They are:
1) The rate of formation of stars in our galaxy.
2) The fraction of those stars with planetary systems.
3) The number of planets per solar system with an environment suitable for life.
4) The fraction of suitable planets on which life actually appears.
5) The fraction of life-bearing planets on which intelligent life emerges.
6) The fraction of civilizations that develop a technology that releases detectable signs of their existence into space.
7) The length of time such civilizations release detectable signals into space.
If you knew each of these probabilities, you could calculate how many planets in our galaxy might be inhabited by intelligent beings with whom we could communicate. Drake gave each of these parameters a number or probability, but they were wild guesses. Once you have the numbers, all you need to do is multiply each of these variables by each other.
Let me explain. What are the odds of drawing the ace of spaces from a card deck twice in a row back to back? The odds of drawing one ace of spades out of a full deck is 1 out of 52 since there are 52 cards in a deck. To calculate the odds of doing that twice in a row would be 1 out of 52 times one out of 52. You multiply the individual probabilities, so the total probability would be one out of 2704. If you knew the likelihood of each parameter in the Drake equation, multiplying them together would give you the theoretical odds that we could receive radio communication from intelligent life on another planet in our galaxy.
Going back to the card analogy, if you drew one time out of a deck of 52 cards, the odds would be one out of 52. If you drew the ace of spades 52 times in a row, the number would be astronomical since you would multiply the result 52 times! The problem with the Drake equation is that the parameters are unknown and are probably unknowable.
There are also variables that the Drake equation didn’t include, such as the type of star. For example, a supermassive star will have a very short life expectancy. Researchers at Rice University reported in January of 2020 that many stars have extended magnetic fields which overlap the Goldilocks zones of most exoplanets. (As we have explained before, we say that a planet is in the Goldilocks zone when it can contain water in the liquid state). These strong magnetic fields will strip away any atmosphere the planet might have. Our Sun has a magnetic field, but it is not strong enough to strip electrons from atoms and molecules in the Goldilocks zone where Earth is located.
More variables regularly show up, and they tell us that our solar system and Sun have been carefully designed and formatted so that we can exist. Psalms 1:19 continues to take on new meaning with every discovery we make in space. “The heavens (do) declare the glory of God, and the firmament (does) show His handiwork.”
— John N. Clayton © 2020
Reference: Astronomy magazine March 2020, page 9.
Frank Drake was involved in the founding of the Search for Extraterrestrial Intelligence (SETI), which we have discussed previously HERE and HERE and HERE.