People who know me know that I’m a somewhat obsessive Carl Sagan fan. (We don’t need to go into too many details, but while some people imagine their lives having theme music, mine has voiceover narration.) I was therefore excited to see that we have an effort to investigate Carl Sagan’s claim that there are more stars in the universe than grains of sand on all of the Earth’s beaches. The answer (well, estimate, really), via Fraser Cain at io9, is that yes, there probably are more stars than grains of beach sand (I’m not sure what Carl Sagan had against deserts.)
The total number of stars in the universe might be somewhere between 10 and 200 sextillion (that’s 1×10^22, or 10,000,000,000,000,000,000,000). The number of grains of sand on beaches (bear with me here) is somewhere between 2.5 and 10 sextillion. So Carl Sagan was right, maybe.
Also, in case you think 10 sextillion is a big number, you might wonder how much space that many atoms would occupy. Per io9, “about four times smaller than a dust mite.” Ponder that, but watch out for the existential dread.