There are 200 billion to 2 trillion galaxies, and in the Milky Way alone we have located at least 10 planets in the Goldilocks zone. That could mean at least 2 to 20 trillion Goldilocks planets, and this is an under-estimate because the scale of our search has been comparatively small. So it is likely that there actively exists plenty of tool-using, scientific, space-faring life forms out there as you read this.
As for time scales, the heat death of the universe is estimated to occur in 1.7x10^106 (or, written out, 17000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000) years. Many, many planets will move into or out of Goldilocks zones in that time. And, depending on the source and the age of the information, we estimate the age of the universe to be 13 or 26 billion (or, 26,000,000,000) years. I added zeros so the two numbers could be visually compared, and you can see we are a very young universe.
Combine these two points and you have ample time and opportunity for many, many civilizations to rise and fall. Where ten planets’ stars may be exploding, ten more may be just entering the prime conditions for life. So take comfort in the thought that we are, statistically speaking, not alone out here.
There are 200 billion to 2 trillion galaxies, and in the Milky Way alone we have located at least 10 planets in the Goldilocks zone. That could mean at least 2 to 20 trillion Goldilocks planets, and this is an under-estimate because the scale of our search has been comparatively small. So it is likely that there actively exists plenty of tool-using, scientific, space-faring life forms out there as you read this.
As for time scales, the heat death of the universe is estimated to occur in 1.7x10^106 (or, written out, 17000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000) years. Many, many planets will move into or out of Goldilocks zones in that time. And, depending on the source and the age of the information, we estimate the age of the universe to be 13 or 26 billion (or, 26,000,000,000) years. I added zeros so the two numbers could be visually compared, and you can see we are a very young universe.
Combine these two points and you have ample time and opportunity for many, many civilizations to rise and fall. Where ten planets’ stars may be exploding, ten more may be just entering the prime conditions for life. So take comfort in the thought that we are, statistically speaking, not alone out here.
Have you seen the Fermi equation? Habitable planets aren’t the only variable.