How Many Atoms Are in the Universe?

Answer 1

10^78 is the best guestimate available,

7 x 10^22 is the best guestimate available for the number of stars in the observable universe.

This is dwarfed by the number of possible 40-move chess games which is about 10^120

Answer 2

It is very sad to see 23 such dumb answers so far and only 3 sensible ones. The number of atoms in the Universe can be very reasonably estimated from known and observed data. The most reasonable estimate is 10^80, and it is quite possibly 10^79 or 10^81, but we can be confident that it is not as little as 10^78 or as much as 10^82.

Answer 3

Several assumptions: The universe is expanding at such a rate that gravity just fails to halt it (similar to escape velocity prob). The age of the universe is about 10billion years+/-2 or 3! And the hubble constant (related to expansion rate) is about 75km/s per megaparsec. This gives a density of about 200 proton masses per cubic meter (average), and approx 10^81 proton masses for whole universe (1proton=1hydrogen nucleus) {10^81=1 followed by 81 zeros- a big lotto win!}

Answer 4

we need a constant lets take einstein theory that the universe is finite as a constant.

approximation of the number of atoms in our galaxy is (highest estimate including dark and exotic matter) 10 to the power of 69 or 10^69

our galaxy is of average size, some are larger others are smaller that's our second constant

the number of galaxies in the universe (highest estimate) 1 trillion or 10 ^12

so the equation is:

the number of atoms in a average galaxy 10^69
X
the number of galaxies in the universe 10^12
=
the number of atoms in the universe 10^81

answer is 10^81 or
1,000,000,000,000,000,000,
000,000,000,000,000,000,
000,000,000,000,000,000,
000,000,000,000,000,000,
000,000,000 atoms

Answer 5

I read on the back of a box of matches once that the number was 7.9x10^89 or something thereabouts. I do realise that just a couple of digits out means an astronomical amount but c'mon gimme a break

Answer 6

Try to imagine how many atoms are in your body and then try to grasp the idea of counting or presuming how many of them are in the universe

Answer 7

we do not know the size of our universe, this results in us not knowing how many atoms there are in the universe. my guess would be about one less than infinity. theres millions of atoms in just one house. in a universe its like a one with as many zeroes behind it as you can possibly fit into this comment box.

i tried to do it but know otherwise- it might have been classified as spam...

Answer 8

A man was once asked how many stars were in the heavens. His reply was that if one counted all the grains of sands ,on all the beaches of the Earth ,it wouldn't reach the number of stars in the heavens. If one were to ask the same question about how many atoms were there in the universe , he will have mulitiply by infinity ,those beaches.

Answer 9

Well let's see...the radius of the observable universe is 3^26 meters and there are 1 to 2 hydrogen atoms per cubic meter. Do the math and you've got your answer (approximate).

Answer 10

The fact your asking in a quantitive figure, with a resolute definitive, shows your logical proccesses cannot compute the absolute answer, not without quantifying it, at least to what you comprehend, a numerical system, therefore, it will not be possible to implant the answer, certainly not by means of typological representation, as even the complex means of doing so could not relate to visual crainial beta representaion, even though the proccess would be possible, i believe in your crainial proccesses could not compute the algorythm, let alone the answer.