How Many Stars are in the Universe?

Michael Anissimov
Michael Anissimov

Scientists estimate that there are between 3 and 7 x 1022 stars in the universe, or between 30 and 70 billion trillion. This is actually a relatively small number by some standards. For instance, the number of atoms in the Earth is roughly 1050, and the number of atoms in Mt. Everest is about 1040. The number of atoms in half a kilogram of rock is roughly 1025. Avogadro's number, which represents the number of atoms in 12 grams of carbon, is about 6 x 1023.

It is estimated that the universe contains between 30 and 70 billion trillion stars.
It is estimated that the universe contains between 30 and 70 billion trillion stars.

The stars in the universe are aggregated into many layers of organization -- beginning with star clusters, which coalesce in galaxies, which are members of galaxy clusters, which are in turn members of superclusters, which are in turn members of super-superclusters, all the way up to the largest features in the universe, such as the Great Wall, a galactic supercluster which is about half a billion light-years long, a third of a billion light-years wide, and 15 million light-years thick. At its highest level of organization, the galactic clusters are distributed in "filaments and voids," thin filaments of galaxies separated by vast voids.

Our own galaxy contains 200-400 billion stars.
Our own galaxy contains 200-400 billion stars.

The typical unit of organization in the universe, the galaxy, contains anywhere between about 10 million and one trillion stars. Our Milky Way Galaxy contains between 200 and 400 billion stars, depending on the exact number of low-mass dim stars, which is highly uncertain. There are approximately 80 billion galaxies in the observable universe, a similar number to the number of stars in a galaxy. These galaxies are spread out across a universe that is at least 93 billion light-years in diameter, and perhaps much larger. 93 billion light-years is only the diameter of the universe that we can see -- the visible universe -- reaches of the universe beyond this are concealed by the cosmic microwave background radiation, a field that is created by the hot plasma that was omnipresent in the first 300,000 years after the Big Bang.

Space telescopes are used to gather information about the stars in the Universe.
Space telescopes are used to gather information about the stars in the Universe.
Michael Anissimov
Michael Anissimov

Michael is a longtime wiseGEEK contributor who specializes in topics relating to paleontology, physics, biology, astronomy, chemistry, and futurism. In addition to being an avid blogger, Michael is particularly passionate about stem cell research, regenerative medicine, and life extension therapies. He has also worked for the Methuselah Foundation, the Singularity Institute for Artificial Intelligence, and the Lifeboat Foundation.

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Discussion Comments


Maybe think of it this way: the number of grains of sand is finite. For all we know, the universe is infinite.


While it is impossible to truly grasp the essence of such numbering or vastness, it is still a fun mental exercise to try. I cannot fathom a trillion of anything, but 70 billion trillion with each averaging a minimum of a million miles across? The human mind is not designed to comprehend such amazing concepts.

In all of our infantile exploration and attempts at understanding, I am comfortable in accepting that our perception of the universe and its true nature and size is at the best comparable to the ancients believing the world was flat and you'd fall off if you sailed too far. The sun being controlled by the gods was also another failed mentality (but that is another rant). Just when people think they are "all that", they just need to look upward at the night sky and should be instantly put in their microscopic place if they know what is good for them. End rant.


Star constellations have been formed arbitrarily by cultures which project their belief systems onto the night sky. Science has caused us to realize how incredibly small we are compared with these stars, and forming constellations would now seem somewhat audacious, considering our infinitesimal tininess.


Star gazing is an exciting hobby, especially when you have access to a powerful telescope. The wonder of the night sky only increases the more you can see. I enjoy going up to the mountains away from any light pollution and just looking up at the sky. It is truly beautiful, especially with an aurora taking place.


The Old Testament uses sands of the sea and stars in the sky as a metaphor for a vast number. God told Abraham that his descendants would be "more than the stars in the sky or sands in the sea." This number is not supposed to be taken literally, because that many people could never fit on the earth, and could form a chain of people which could reach to the nearest galaxy.


There are vastly more stars in the universe than there are grains of sand on the earth. To try to grasp this immense number of stars is beyond us. Each one of these stars is infinitely larger than us, and there are more of them out there than grains of sand on all the beaches and deserts of the earth.

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