Clyde Tombaugh, who was born on this day in 1906, grew up on a farm in Kansas and was captivated by sights of the moon and ...

In 1930, scientists discovered a small celestial body on the outer edge of our solar system. They called it Pluto and classified it as a planet. However, the International Astronomical Union (IAU) — ...

The science community may be ecstatic over the discovery of a ninth planet, but the former planet "Pluto" had a totally different reaction. Hours after scientists announced there's solid evidence of ...

The heart's brightness arises from sunlight reflection, while red patches, formed by tholins, showcase Pluto's atmospheric ...

It's going on two years since the International Astronomical Union rewrote its definition of a planet and busted Pluto down to something it called a "dwarf planet." But it's not a done deal, says Mark ...

1. What is a planet? -- 2. Seven perfect planets made of aether -- 3. The Earth becomes a planet -- 4. Sixteen planets -- 5. Not everything that orbits the Sun is a planet -- 6. Uranus! -- 7. The ...