Neptune as seen by Voyager 2. Credit: NASA/JPL

Though it may be hard to believe, Neptune, once again the farthest planet from the Sun (in our solar system) thanks to Pluto’s demotion, completes it’s first orbit around the Sun in two day’s time.  What that means is that on August 20th, Neptune will have traveled fully around the Sun for the first time since it’s discovery on September 23rd, 1846.

For those counting that’s about a 60,189 day orbit or 164.8 years (Earth years of course).  Although this is the first time Neptune will make the journey as a planet, it’s not actually the first time it has orbited since being seen by humans.  Everyone’s favorite astronomer and Queen reference, Galileo Galilei actually saw Neptune twice, first on December 28th, 1612 and then again on January 27th, 1613 but mistook the planet for a star thanks to a woefully underpowered telescope and happening to observe the planet during it’s “stationary” period (where the relative motion of the Earth and a planet cause the planet to appear stationary in the sky).

More fun facts about Neptune?  OK.  Neptune’s day is only 16.11 hours.  Neptune’s orbit has an eccentricity of 0.01 meaning that it is nearly circular, especially compared to Pluto’s highly elliptical orbit.  When Pluto was still a planet (poor Pluto, I pine for you) these orbital patterns would make it so Neptune was actually the 9th planet from the Sun for about 20 years of every 248 year orbit of Pluto.  That last happened from 1977 to 1999 (I said about 20!).

Side note, since Pluto was discovered in 1930 and has a 248 year orbit, I’ll be long dead before that happens so I’ll have to schedule a post for 2178 and hope that my well wishes to our Plutonian Robot Overlords are received, and then they clone me or something.  I’ll attach a DNA sample to the post …

Anyway, Happy New Year Neptune!  I’m going to go do the Fandango.