Almost 10 years ago, a NASA spacecraft was able to take several photos of Pluto, known for decades as a planet before it was ...

Instead, it was a job offer (from the head of the Observatory, no less), and ... the starry background, roughly where Lowell ...

came up with a new definition of planets that leaves Pluto out in the cold. The problem was that the term "planet" had no firm definition, just as in geology, "continent" remains a somewhat ...

The Pluto-Kuiper Express is currently slated to become the first spacecraft to visit the mysterious world, the smallest and usually farthest planet-like body from the sun. The Planetary Society on ...