I think it is because the Drake equation[1] over-estimates the chances of intelligent life forming.
A common average result for the Drake equation is 10,000 habitable planets capable of sending signals in our universe. But if you look at the equation and estimates they are a bit optimistic.
If you take fℓ from the equation, I don't think simply being of the right composition in the habitable zone is enough. The Earth formed life because of the moon, because we had been shiften off our axis which formed seasons, because we were made of enough iron to form a magnetic field, and we just happen to form a moon which protected the Earth from space debris and gave us tides (in short, the moon and magnetic field are essential to life on Earth, as well as the composition of the planet).
That is a lot of 'ifs' to add to the equation, which brings the chances of a planet even in the habitable zone having the same life-bearing characteristics as earth much, much lower. Even with thousands of planets in the habitable zone the chances of finding one that has a magnetic field, the right temperature, a moon, etc. are very very slim and when multiplied back into the Drake equation brings the result back to lower than 1 - meaning we are a complete fluke.
There is also the time portion of the equation. The Earth is 4.6B years old, and we have been capable of sending signals for only 100 years of that time. Even if our civilization survives for another 10,000 years it is still 10,000 years divided into 4.6B years - so even with the complete fluke of an Earth-like planet being created in a habitable zone takes place, we are still 1 in 460,000 chance of being around at the same time. If Drake gives us 10,000 possible habitable planets with life, the 1 in 460,000 factor of time brings it back to a lot less than 1 again.
I believe that Keppler will continue finding planets in the habitable zone, but they will look more like Mars and Venus than anything like Earth.
I find it interesting that the Drake equation, created to show that there must be other intelligent life, can today be used to show that we are very unique when it is adapted with what we know today.
[1] https://en.wikipedia.org/wiki/Drake_equation#The_equation
The problem with the Drake equation is the huge uncertainty in the factors. I propose instead that we get someone at Microsoft to estimate the number of piano movers in the universe and estimate from there.
A common average result for the Drake equation is 10,000 habitable planets capable of sending signals in our universe. But if you look at the equation and estimates they are a bit optimistic.
If you take fℓ from the equation, I don't think simply being of the right composition in the habitable zone is enough. The Earth formed life because of the moon, because we had been shiften off our axis which formed seasons, because we were made of enough iron to form a magnetic field, and we just happen to form a moon which protected the Earth from space debris and gave us tides (in short, the moon and magnetic field are essential to life on Earth, as well as the composition of the planet).
That is a lot of 'ifs' to add to the equation, which brings the chances of a planet even in the habitable zone having the same life-bearing characteristics as earth much, much lower. Even with thousands of planets in the habitable zone the chances of finding one that has a magnetic field, the right temperature, a moon, etc. are very very slim and when multiplied back into the Drake equation brings the result back to lower than 1 - meaning we are a complete fluke.
There is also the time portion of the equation. The Earth is 4.6B years old, and we have been capable of sending signals for only 100 years of that time. Even if our civilization survives for another 10,000 years it is still 10,000 years divided into 4.6B years - so even with the complete fluke of an Earth-like planet being created in a habitable zone takes place, we are still 1 in 460,000 chance of being around at the same time. If Drake gives us 10,000 possible habitable planets with life, the 1 in 460,000 factor of time brings it back to a lot less than 1 again.
I believe that Keppler will continue finding planets in the habitable zone, but they will look more like Mars and Venus than anything like Earth.
I find it interesting that the Drake equation, created to show that there must be other intelligent life, can today be used to show that we are very unique when it is adapted with what we know today. [1] https://en.wikipedia.org/wiki/Drake_equation#The_equation