Imagine predicting an entire planet's existence with nothing but math, and then finding it right where the numbers said it would be. The story of Neptune's discovery is unlike any other in astronomy.

It might seem unfathomable to us living today, but 179 years ago on this very date, our galaxy, The Milky Way, actually grew by one planet. Okay, okay, we know, that that is not what actually happened ...

The eighth and most distant planet from the sun, Neptune, reaches opposition with the sun on Sept.23, when it will be in its best position for viewing for the year. Neptune is too faint to see with ...