How many planets exist? As the sand of Earth’s beaches…

So, fun fact for the day!

There are at least between 1/4 – 1/2 trillion stars in our galaxy & scientists (Caltech) now estimate there’s at least 1 planet per star, possibly many more.

+ There are about 1/2 trillion galaxies in the known universe, each with about as many stars and planets as ours. The cosmos & galaxies can be very disparate so these are pretty rough averages but models the right neck of the woods.

Multiply “hundreds of billions” by “hundreds of billions” and you get a fairly unfathomable number. It turns out to be somewhere around the number of grains of sand on all the world’s beaches … that’s how many planets are in the observable universe.


There’s a lot of sand, and that’s a ton of planets. Oh but here’s where things get really fun. A significant portion of them—perhaps 1/3 or more—are earth-like terrestrial planets. This doesn’t even count “rogue planets“, free-floaters ejected from their solar systems and lost to utter the darkness of space. There are at a minimum twice as many of those so two times the world’s beaches and potentially 100,000 to each 1 star. And the exciting science of extremophiles has begun teaching us that they could harbor life as easily as could the hidden oceans inside Jupiter or Saturn’s – no sunlight required thank you!


The very best part of all? These are approximations for the observable universe only. Like, potentially just scratching the surface. Many scientists believe that at a bare minimum all of this is actually just a teeny tiny corner under the couch of the vast expanse of reality. Or, as one NASA site puts it, we can only observe a finite volume of the Universe. All we can truly conclude is that the Universe is much larger than the volume we can directly observe.

So next time you go to the beach bring home a jar full of sand to serve as a reminder of all that is out there: the unimaginable number of planets that likely includes a great number just like ours… and whatever they contain.



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