--- title: "How many atoms are there in the universe? about 10^80" description: "about 10^80 How the figure is estimated, how confident it is, and what makes the scale graspable." url: https://atoneplace.net/how-many/atoms-in-the-universe/ site: "At One Place" --- # How many atoms are there in the universe? **How many atoms are there in the universe?: about 10^80** There are roughly 10^50 atoms in the Earth, so the observable universe holds about 10^30 Earths' worth of matter. And there are still vastly more possible chess games than atoms. The standard answer is 10^80 atoms in the observable universe, and unusually for a number this large it is a calculation from well-measured cosmology rather than a guess. Ordinary matter is only about 5% of the universe's energy density; dark matter and dark energy make up the rest and are not made of atoms. About 90% of the atoms by number are hydrogen. The figure applies strictly to the observable universe — beyond the horizon there may be arbitrarily more. ## How the figure is arrived at Three published numbers multiplied together. The observable universe is a sphere of radius 4.4 × 10^26 m, giving a volume of 3.6 × 10^80 m³. The critical density is about 8.6 × 10^-27 kg/m³, of which baryonic matter is 4.9%, so 4.2 × 10^-28 kg/m³. Multiply for a total baryonic mass of 1.5 × 10^53 kg and divide by the mass of a hydrogen atom, 1.67 × 10^-27 kg: about 9 × 10^79, or 10^80 to the nearest power of ten. ## How confident it is - **Low estimate:** 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 - **High estimate:** 10,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 - **Spread:** 10000.0× between the bounds ## Other space and the universe counts - [How many stars are there in the universe?](https://atoneplace.net/how-many/stars-in-the-universe/) — about 200 billion trillion - [How many stars are there in the Milky Way?](https://atoneplace.net/how-many/stars-in-the-milky-way/) — between 100 billion and 400 billion - [How many galaxies are there?](https://atoneplace.net/how-many/galaxies-in-the-universe/) — hundreds of billions — possibly 2 trillion - [How many satellites are in orbit?](https://atoneplace.net/how-many/satellites-in-orbit/) — about 12,000 active satellites - [How many moons are there in the solar system?](https://atoneplace.net/how-many/moons-in-the-solar-system/) — about 900 confirmed, and the number keeps moving - [How many planets are there in the galaxy?](https://atoneplace.net/how-many/planets-in-the-milky-way/) — at least 100 billion — probably more planets than stars - [How many stars can you see with the naked eye?](https://atoneplace.net/how-many/stars-visible-to-the-naked-eye/) — about 9,000 over the whole sky; roughly 2,500 at once - [How many constellations are there?](https://atoneplace.net/how-many/constellations/) — exactly 88 - [How much space junk is there?](https://atoneplace.net/how-many/space-debris/) — about 40,000 tracked objects, and over 130 million fragments too small to track - [How many asteroids are there?](https://atoneplace.net/how-many/known-asteroids/) — about 1.4 million catalogued ## Common questions ### How many atoms are there in the universe? about 10^80 ### How is that estimated? Three published numbers multiplied together. The observable universe is a sphere of radius 4.4 × 10^26 m, giving a volume of 3.6 × 10^80 m³. The critical density is about 8.6 × 10^-27 kg/m³, of which baryonic matter is 4.9%, so 4.2 × 10^-28 kg/m³. Multiply for a total baryonic mass of 1.5 × 10^53 kg and divide by the mass of a hydrogen atom, 1.67 × 10^-27 kg: about 9 × 10^79, or 10^80 to the nearest power of ten. ## Related pages - [How many stars are there in the universe?](https://atoneplace.net/how-many/stars-in-the-universe/) - [How many stars are there in the Milky Way?](https://atoneplace.net/how-many/stars-in-the-milky-way/) - [How many galaxies are there?](https://atoneplace.net/how-many/galaxies-in-the-universe/) - [How many satellites are in orbit?](https://atoneplace.net/how-many/satellites-in-orbit/) - [How many moons are there in the solar system?](https://atoneplace.net/how-many/moons-in-the-solar-system/) - [How many planets are there in the galaxy?](https://atoneplace.net/how-many/planets-in-the-milky-way/) - [How many stars can you see with the naked eye?](https://atoneplace.net/how-many/stars-visible-to-the-naked-eye/) - [How many constellations are there?](https://atoneplace.net/how-many/constellations/) - [How many people are there in the world?](https://atoneplace.net/how-many/people-alive-right-now/) - [How many countries are there in the world?](https://atoneplace.net/how-many/countries/) - [How many bones are in the human body?](https://atoneplace.net/how-many/bones-in-the-human-body/) - [How many grains of sand are there on Earth?](https://atoneplace.net/how-many/grains-of-sand-on-earth/) - [How many ants are there in the world?](https://atoneplace.net/how-many/ants-on-earth/) - [How many trees are there in the world?](https://atoneplace.net/how-many/trees-on-earth/) ## Sources - Calculated on this page — At One Place (/about/)