Why I am not a believer in Flying Saucers visiting us

My form of the Drake Equation:

N=ns*np*nl*nmc*ncmc*nil*nt

Whe

N = number of civilizations EVER in the galaxy
n = fraction of stars including brown dwarfs
np = fraction of stars having planets
nl = fraction having even single celled life
nmc = fraction having multi-cellular life
ncmc = fraction having complex multi-cellular life
nil = fraction having intelligent life
nt = fraction having technology

Plug in some numbers. I use 4 E 11 for the number of stars. .5 for
the number having planets, .5 for the number having single cellular
life, .03 for the number having multi-cellular life, .3 for the
fraction having complex multi-cellular life, .3 for the fraction
having intelligent life, and .1 for the fraction developing
technology. This gives only 2.7E7 civilizations EVER in the galaxy.

Now, I make an assumption that seems reasonable to me. That after
100,000 yrs, a civilizations technology will be so advanced that it
will “disappear” from view. That is, it will either destroy itself
(unlikely) or will encode itself into the information contained in the
universe so it has no conventional physical form. You may not agree
with this but it makes sense to me given the rate of technical
advances.

I assume that the universe is about 15 billion years old and that life
could not begin to exist until about 5 billion years later when there
was sufficient “metal” in the universe from fast burning stars. So,
since 10 billion years ago, there have been only 100,000 civilization
lifetimes. Divide the number of civilizations EVER in the galaxy by
this number of lifetimes and you get an estimate of the number of
visible civilizations in the galaxy NOW. I get ………only, 270.

270 is a small number in a big galaxy.

Now, the Milky Way galaxy is 100,000 light years (LY) radius and 2000
LY thick giving a volume of 1.26E14 cubic LY or CLY. Assume our
civilizations are spread equally throughout giving each one 4.65 E11
CLY. What is the distance to the edge of such a cube with this
volume, this distance being the distance to the “boundary” of the next
civilization? Simple, take the cube root of this number and divide by
2 giving 3870 LY. This means we can expect that the closest
civilization to be no closer than 3870 LY although since we assumed
the civilizations are located at the center of these cubes it is
actually double this distance or 7740 LY.

I assume that any ET visiting earth can not move faster than c. If
they can move faster than c then the universe gets enormously bigger
because they are no longer constrained by moving just one direction in
time so they could just as easily visit all of the 27 million
civilizations that have ever existed before us and all of those that
will exist after us and soon one civilization will look like another.
Really, how many data points do you need?
So, our ETs move below c.

Say, 10,000 years ago, using gravitational lensing from a star, our
ETs looked at earth and saw the beginnings of civilization. Well, it
took the light from those mud huts 7740 years to reach them before
they hopped in their spaceships moving at .999c meaning their
spaceships will be here in 2260 years.

Now, you can change any of my numbers a lot, say increase the age of a
civilization by a factor of 10 to be a million years and the ultimate
result does not change much, it is still a very long way (over 1000
LY) to the nearest civilization. You would have to change two or more
of my numbers by a large amount to get much of a change and I think
this is unlikely.

Consequently, I do not believe in flying saucers.