Are there aliens out there in space?
How many alien civilizations are there?
Why haven’t aliens communicate with us?
Astrophysist Frank Drake wanted to encourage astronomers to consider alien civilizations. SETI, the Search for Extra Terrestrial Intelligence was just beginning and needed funding.
So one day at Greenbank West Virginia, taking a break form observing with the giant radio telescopes there, put pen to paper and created the Drake Equation. There is a plaque the in that room commemorating that equation. (See the featured image.)
There is an interactive version of the Drake equation at this BBC web site. At that BBC site, you can change the number of each variables.
I calculate almost two thousand advanced alien civilizations right now in our Milky Way galaxy.
N* is the number of detectable civilizations in the Milky Way. We will solve for N*. Here’s the Drake Equation:
N* = R* fp Ne fl fi fc L Nr
How many new stars begin fusing hydrogen into helium each year in our galaxy? Recent observations indicate that 7 new stars appear annually, not ten. The January 5 issue of Nature magazine describes the research,
What percentage of stars have planets? Scientists use to estimate this at about 50% The Kepler space telescope has shown us that just about every star observed has at least one plant.
How many of those planets would be like the Earth? For our solar system, I count one
Earth-like planet for 8.
How many Earth-like planets will have life? Right now our one example shows us 100% I’m going to be a little conservative here and say 50%
What’s the chance that that life will become intelligent? Again, our one example is 100% and again I choose to be conservative at 50%
What’s the chance that intelligent life will develop communication like radio? Again I go 50%
How long will such a civilization last on average? I’m going very conservative here. Let’s hope we last a million years.
How many times can our civilization bounce back from a catastrophe. Nuclear War, Climate change, Killer Asteroid? I guess once.
Do I believe in aliens?
No, I don’t, and…
For my best guess at the variables, I calculate a mere 1,929 intelligent, communicating civilizations in our galaxy right now.
That’s about 300 trillion in the whole known universe. I think alien civilizations are probably out there.