Well to begin with i would calculate all the countable space in the universe in the smallest units possible (Planck lengths). Then i would calculate the total lifespan of the universe in Planck time units. After that i multiply the last two results to get the total amount of countable space in the universe times the amount of countable time in the whole lifespan of the universe.
Total space in universe calculation:
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Planck length in meters:
1.6 x 10^-35 =
0.000000000000000000000000000000000016
Diameter of the universe in meters:
8.8 x 10^26 =
880000000000000000000000000
Diameter of universe in Planck lengths:
5.4453761 x 10^61 =
54453761000000000000000000000000000000000000000000000000000000
Volume of universe in Planck cubes:
1.61467 x 10^185 =
161467000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
Total time of universe calculation:
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Current age of universe till now in years:
13.7 x 10^9 =
13700000000
Time from now till universe heat death in years:
1.7 x 10^106 =
17000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
Total life (past + future) of universe in years: (insignificant difference)
1.7 x 10^106 =
17000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
Total life of universe in seconds:
5.3618 x 10^113 =
536180000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
A few more calculations...
Planck lengths per light second (number of plank lengths light travels in 1 second):
1.855 x 10^43 =
18550000000000000000000000000000000000000000
Universe Planck volumes per second over total life of universe:
9.946139 x 10^156 =
9946139000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
Universe Planck volume * Planck time instances over life of universe:
1.605973225913 x 10^342 =
1605973225913000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
After that i can add matter into the mix by calculating the number of subatomic and atomic particles in the universe at any one plank time instance. Then we multiply that number into our last result.
Number of subatomic and atomic particles in the universe:
3.28 x 10^80 =
328000000000000000000000000000000000000000000000000000000000000000000000000000000
Result for all countable things in the universe so far:
5.267592180994640 x 10^422 =
526759218099464000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
We can add a few more things like stars planets and galaxies:
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Stars in the universe:
10^24 =
1000000000000000000000000
number of planets in the universe (star orbiting and rogue planets):
10^51=
1000000000000000000000000000000000000000000000000000
number of galaxies in the universe:
13 x 10^15 =
13000000000000000
All stars, planets, and galaxies in the universe:
1.3 x 10^91 =
13000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
My final result:
6.847869835293032 x 10^513 =
6847869835293032000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
This number can be significantly larger if we multiply in the number of molecules in the universe along with the number of space dust particles, asteroids, comets, black holes, and whatever else i'm missing.