There are more stars in the universe than grains of sand on all of Earth's beaches.

Calculating the number of sand grains involves estimating the total volume of Earth's beaches and deserts. Researchers at the University of Hawaii estimated that if you assume a grain of sand has an average size, there are approximately 7.5 x 10^18 grains on Earth. This number, 7.5 quintillion, is a staggering figure that covers every coastline and desert on the globe.In contrast, astronomers use data from deep-space surveys to estimate the number of stars. By counting galaxies in a specific patch of sky using the Hubble Space Telescope and multiplying by the average number of stars per galaxy, scientists reach a total of roughly 70 sextillion stars. This is represented as a 7 followed by 22 zeros, which is significantly larger than the sand count.The calculation assumes there are about 100 billion to 400 billion stars in our Milky Way alone. With an estimated two trillion galaxies in the observable universe, the math quickly outpaces any terrestrial comparison. This means that for every grain of sand on Earth, there are roughly 10,000 stars in the sky.These estimates only account for the observable universe, which is the portion of space light has had time to travel from since the Big Bang. Because the universe is expanding, the actual number of stars could be even higher or even infinite. This comparison remains one of the most popular ways for educators like Carl Sagan to illustrate the sheer scale of the cosmos.