“The universe is a pretty big place. If it's just us..."

I see this quote by Carl Sagan a lot:
“The universe is a pretty big place. If it's just us, seems like an awful waste of space.”

So that got me curious. What if every planet in the universe had alien life? And what if every planet was a Jupiter sized planet? And what if every planet had a population proportional to Earth's population. Would that still be a waste of space?


Estimated Number of Planets in the Universe: 1e+24 or 1 septillion or
1,000,000,000,000,000,000,000,000

Volume of Jupiter (our largest planet): 1.43e+15 cubic kilometers

I multiplied the two numbers above to get:
Volume of all planets in the Universe: 1.43e+39 cubic kilometers

Volume of the Universe: 3.58e+71 cubic kilometers

So dividing the volume of all planets by the volume of the universe I get: 3.99e-33 or
0.000000000000000000000000000000399 % (percent)

So, if you subtract the percentage of volume of all planets from the 100% volume of the universe, the universe is still essentially at 100%.


Ok. Carl Sagan said "If it's just us..." To me that means if there were more of us, more aliens in the universe, then it wouldn't be a waste of space.

So let's do it by the volume of all alien flesh in the universe.

World Population: 7,400,000,000 or 7.4 billion people


Average weight of adult an on Earth: 62 kg (136.7 lbs)
Average volume of adult on Earth: 0.062 cubic meters

World Population (X) 0.062 cubic meters= 458,800,000 cubic meters of flesh.


In terms of surface area, Jupiter is 121.9 times bigger than the Earth.

121.9 (x) 458,800,000 = 55,927,720,000 cubic meters of alien flesh on Jupiter.


55,927,720,000 cubic meters (X) 1,000,000,000,000,000,000,000,000 Jupiter sized planets =

5.592772e+34 cubic meters

So there would be approximately 5.59e+34 cubic meters of total alien flesh in the universe.

Volume of the Universe: 3.58e+80 cubic meters

So dividing total volume of alien flesh by volume of the universe, we get
1.56e-46.

So the volume of all alien flesh in the universe represents
0.0000000000000000000000000000000000000000000156 % (percent) of the universe.

That's about as close as zero as you can get.

So, having every planet in the universe being populated by human sized aliens adds nothing to the universe.

It's still a waste of space.