A Happy Belated Birthday to Neptune

[LongTomH]

Break out the cake and party favors the planet Neptune is one (Neptunian) year old! :party:



Phil Plait at his Bad Astronomy blog wishes the planet: Happy Birthday, Neptune! and explains:

Today is special: it is now one full Neptunian year since this giant planet was discovered in 1846!

Although, as Phil goes on to explain, it's a bit more complicated than that:

First, to celebrate a birthday, you need the birthdate. That’s the first complication. Neptune was discovered on September 23, 1846 by astronomer Johann Galle using star charts by Johann Encke, and they are generally given credit for it. However, that date of September 23 is a bit dicey! Galle and Encke report that they found Neptune on 9/23 at 12:00:15 "Berlin M.T.", according to Westfall. But they reckoned the day starting at noon! And since they’re using Berlin mean time, you have to account for the longitude of Berlin with respect to 0° longitude on Earth. According to Westfall, once you do all that, you get a discovery time of September 23 at 23:06:40.

It gets even more complicated! It seems that Jupiter's gravity has enough of an influence on Neptune's orbit that it's year may actually be variable. And, things get really interesting when you consider that the center of Neptune's orbit isn't the sun's center, but, the solar system barycenter:

In fact, it’s not that simple (stop me if you’ve heard that before). Neptune actually orbits the solar system’s barycenter, its center of mass. You might think that would be the center of the Sun, but Jupiter is big enough to pull on the Sun a bit, making the entire solar system off-center (think of it like an adult and child holding hands and spinning around; the mass of the kid pulls the grownup a bit off-center as they circle each other — or just look at the animation here and let yourself get dizzy). The other planets contribute as well. This makes things a lot harder to figure out, and this is getting ridiculous as it is.

Fair makes your head spin, doesn't it? :crazy:

At least, Neptune takes a pretty picture for his birthday, doesn't he?

[midnight]

1. Beautiful electric blue color....

[krispos42]

2. Wjhen the Voyager 2 pics came back in 1989...

...PBS carried them live from NASA. I stayed up until the wee hours of the morning (4am?) to watch them come in.


I was 13.