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I've just done a few (very rough) calculations aimed at showing just how rare life is in our immediate cosmic neighborhood. Wherever '=' occurs below, just consider it to mean 'roughly equal to'. Details of the calculations are available upon request.

As far as we know right now, life in our immediate cosmic neighborhood exists only on a strip of the Earth's surface a few miles thick. Let's be generous and assume this strip to be 200 miles thick. Let BS—BioSphere— stand for the volume (in cubic miles) of this strip. Then

BS = 156,861,815,589 cubic miles

Now, aside from our Sun, the next nearest star to us, Proxima Centauri, is about 5 light years away (roughly 6 trillion miles). Let PC stand for the volume (in cubic miles) of the sphere of space centered on the Earth with radius 5 light years. Then

PC = 1.131 x 10⁴¹ cubic miles

The ratio of BS to PC gives the relative volume of space occupied by life in a sphere of radius 5 light years centered on the Earth:

BS / PC = 1.4 x 10^-30

or

BS / PC = .000000000000000000000000000000014

To say this in words, life occupies no more than about

14 billionths of a trillionth of a trillionth

of the spatial volume in a sphere of radius 5 light years centered on the Earth.

And, of course, when we take into account the fact that a sphere of radius 5 light years contains essentially no spatial volume at all when compared to the spatial volume of the entire visible cosmos (and even less when compared to the spatial volume of our entire inflationary bubble), we begin to get an inkling of just how exiguous life appears to be within the vast scheme of things.

From this point of view, it does seem a bit odd to say that "[t]he universe seems uncannily well suited to the existence of life". If it were so well suited to life, one would think that life would occupy much more of it. Energy is ubiquitous in the universe, life appears to be at the other extreme (as far as we now know).

As a snide aside, let me point out that, using the ordinary acceptations of the acronyms BS and PC, the ratio of BS to PC seems to be pretty nearly 1. But I'll defer a more detailed examination of that ratio to another day.

Correction to previous post:

1 light year is approximately 6 trillion miles, so 5 light years is approximately 30 trillion miles.

Hence the sentence

Now, aside from our Sun, the next nearest star to us, Proxima Centauri, is about 5 light years away (roughly 6 trillion miles).

should read

Now, aside from our Sun, the next nearest star to us, Proxima Centauri, is about 5 light years away (roughly 30 trillion miles).

good number crunching snarks.

But you stopped half-way.

Take your extremely low ratio and extend it across the universe and you end up with lots and lots of places that have life.

But since we are never going to be able to travel to the stars, it is meaningless because we will never ever meet any of that other life.

there are 100 billion neurons in the brain

there are 100 billion stars in the Milky Way

there are 100 billion galaxies in the visible universe

the visible universe is 1 billionth billionth billionth of the whole universe

or so