Are We Alone in the Universe?

Frank Drake
The Drake Equation
N= N* fp ne fl fi fc fL

Frank Drake who was the founder of SETI (Search for Extra-Terrestrial Intelligence) developed the Drake Equation. The equation is used to figure the number of worlds in our Milky Way Galaxy capable of supporting intelligent life.

The equation goes like this:
N* = the (N)umber of stars in our Milky Way.
fp = The (F)raction of stars that have (P)lanetary systems.
ne = (N)umber of planets per star (E)cologically able to sustain life.
fl = (F)raction of those planets where (L)ife actually evolved.
fi = The (F)raction of (fl) that evolves (I)ntelligent life.
fc = The (F)raction of (fi) that communicates.
fL = The (F)raction of the planets (L)ife durring which the communicating civilization survives.

(N*=100 billion) X (fp=50%) X (ne=1) X (fl=50%) X (fi=20%) X (fc=20%) X (fL=1/1,000,000 or 10,000years). Using these numbers then N = 1,000 communicating civilizations in our galaxy. The actual numbers may be quite a bit higher.

1,000 planets just in our own Milky Way Galaxy. Many scientists will tell you that this number is very conservative and the actual number maybe many times higher. Remember that there are billions of galaxies in the universe so the real number of planets with intelligent life could be in the hundreds of billions.

Are we alone? I would have to say probably not. Have we been visited? That’s another thing entirely, maybe, maybe not but that discussion is for another day but makes you think.