Pluto's days, though they drag on a bit at around 153 hours, are nothing compared to its years. Pluto's orbit takes 248 Earth ...

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Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. Many Americans grew up with this as the definitive planetary lineup and created clever mnemonic devices to memorize them in ...

On January 5, 2005, astronomers at NASA discovered Eris, the second-largest dwarf planet in the solar system. Eris is just ...

For the first time since Pluto was demoted, the idea of a true ninth planet is edging from speculation toward something ...

Pluto was a planet in good standing for seventy-six years when in 2006, out of the blue, it was demoted and booted from our solar system’s family of planets. The stunning event – still hotly debated ...

NASA's New Horizons spacecraft captured this high-resolution enhanced color view of Pluto that is inserted beneath the Short Wave logo. The image combines blue, red and infrared images taken by the ...

You know what a planet is, right? A big round thing that orbits a star. Uh, not so fast. You know what a planet is, right? A big round thing that orbits a star. Uh, not so fast. The surprisingly ...

Back when most of us were in elementary school, we were taught that our solar system has nine planets. Then in August 2006, our worlds were turned upside down when astronomy’s official governing body ...

We discovered something: Pluto was different! Pluto was discovered because Neptune’s orbit showed an anomaly that indicated that there was something else out there. So they looked and eventually Clyde ...