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No one can ascertain the answer to this question with absolute certainty due the immensity of the universe and fact that light from vastly distant galaxies has not even had time to reach the Earth. The reason for this is that even though light travels at approximately 300,000 kilometers per second in a vacuum it will still take billions upon billions of years for it to travel from the outer limits of the universe across the seemingly infinite distance to planet Earth.

Yet, in 2003 Australian astronomers set out to answer this very question to the best of their abilities. They used two of the world's most powerful telescopes to observe 10,000 visible galaxies and then extrapolated this data out to the edge of the known universe.

The number they estimated was an astonishing 70 sextillion, written as 70,000,000,000,000,000,000,000 . 70 sextillion is 7 followed by twenty-two zeroes!

More importantly, is there any way for us to even begin to get our minds around a number so large as this?

There is if we descend to the Earth for a few moments and use our imaginations.

Imagine that you are laying on the beach at night, looking up at the expanse of the sky and stars above you, amazed by the surreal feeling of imbibing the cosmos. Countless grains of sand stretch out in all directions beneath you. Hanging in the sky, the moon acts as a sentinel shining its light on the clouds that creep by it like apparitions. Incessantly the waves roll to the shore in curls, spirals, and tumbles and then recede, pulled by the tugging reins of gravity from the moon.

Mesmerized by this thought you walk toward the tide and begin to dig your ankles into the sand beneath your feet as the water splashes over them. Burying your feet in countless minuscule grains of sand as you fixate on those dots of light piercing the night's canopy, you pause to ponder a question that enters your mind.

You think to yourself, "What if I were to walk every beach of the earth, digging my feet into every sand bar, then lay myself down and drag my fingers through every smoothed plane of wet sand to build countless sand castles. How many grains of sand could I count? What if I then were to traverse every cubic millimeter of every desert on this planet Earth, diving into sand dunes and shielding myself from devastating sand storms, but through pure magic were able to tally up every last grain of sand on my feet, every grain surrounding me in the dunes, and every grain blown violently at me from the punishing winds? Surely, I would find that there must be more grains of sand on this planet Earth than there are stars in the universe."

The Australian researchers would say that you were very diligent yet also very wrong. They estimated that there are at least ten times as many stars in the known visible universe as there are grains of sand along every single beach, and in every single desert on the planet Earth.

Inevitably this inspires us to wonder about the possibility of life elsewhere in the cosmos. Dr. Simon Driver, who spoke at the General Assembly of the International Astronomical Union about this calculation, said this when asked about this possibility, "Seventy thousand million million million is a big number ... it's inevitable."

Somewhere on a distant planet, with far fewer grains of sand on his or her own world than exist stars in the universe, may lie an intelligent being peering out into the universe amazed by the very same possibilities that you and I have dared to imagine.

Learn more about this author, Josh Gough.
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