There’s a point to the math

September 28, 2015
Alexis Bouvard's Blue PeriodCredit NASA
Alexis Bouvard's Blue Period

  This is “Looking UP! in southern Colorado,” from the Colorado Springs Astronomical Society. I’m Jim West, and there are lots of reasons to look up!

When looking through a telescope, there are two kinds of objects that make people say “wow.” There are objects that are intrinsically gorgeous on their own, like the Orion nebula or the planet Saturn, and there are objects that make you say wow, not because of their beauty, but because of the awe-inspiring realization of what you are seeing. The planet Neptune, one of my favorite telescope objects, is in the latter group.

Through a telescope Neptune appears as a blue dot, roughly the size of a period at the end of the sentence. But that tiny dot is actually the most distant planet in our solar system -- sorry Pluto fans.

Neptune has the distinction of being the only planet in our solar system located through mathematics. In 1845 strange wiggles in the orbit of Uranus caused astronomers to wonder if there might be another planet farther out, whose gravity was messing with Uranus. In 1846 two different astronomers pointed their telescopes to where the mathematicians said there ought to be a planet, and Neptune was discovered.

Along with Jupiter Saturn and Uranus, Neptune is one four gas giant planets in our solar system. Neptune is a strange and freaky place. It has the highest known winds in the solar system, blowing it over 1300 mph. In spite of its size, it rotates so fast that its day lasts only 16 hours.

It has 14 known moons, one of which, Triton, is the coldest known place in the solar system. The temperature there dips to 391° below zero, yet the only spacecraft to visit Neptune and its moons, Voyager 2 in 1989, observed geysers of liquid nitrogen rising from Triton’s surface. Oh, and Triton orbits Neptune backwards, relative to all the other moons. It almost certainly was a dwarf planet like Pluto, which Neptune captured billions of years ago. All that in a tiny blue dot the size of a period. Wow!

If you’d like to take a closer look at Neptune or any of the other wonderful and amazing things in the sky, please visit or for a link to information on our monthly meetings and our free public star parties! 

This is Jim West for the Colorado Springs Astronomical Society, telling you to keep looking up, Southern Colorado!