Today, Neptune turned 1 year old. Well, sort of.

The eighth planet from our sun was discovered on September 23, 1846. Neptune takes a very long time to orbit the sun 164.8 Earth years, in fact and today Neptune completed its first orbit of the sun since it was discovered. Congratulations!

Now, this got us wondering, when will Pluto complete its first orbit since its discovery? (Yes, yes. Our brains know that Pluto is no longer a planet, but in our hearts ... Pluto!) After all, Pluto is even farther out (most of the time ) than Neptune, and was discovered much more recently. Will we even be around to celebrate it's orbital birthday? To the mathmobile!

Pluto was discovered on February 18, 1930. It takes the dwarf planet 248.09 Earth years to complete one orbit around the sun. Plug all that info into timeanddate.com's handy calculator, and we find that Pluto will complete its first full orbit since its discovery on Monday, March 23, 2178, just a few years after Neptune turns 2.

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