On the 95th anniversary of its discovery, Pluto remains one of the most beloved and enigmatic worlds in our solar system, ...

More pocked with craters than any other object in our solar system, Jupiter's outermost and second-biggest Galilean moon, Callisto, appears geologically unremarkable. In the 1990s, however, NASA's ...

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Saturn, Venus, Neptune, Uranus, Jupiter, Mars and Mercury will be visible in an uncommon planetary alignment this month.

Clyde Tombaugh discovered Pluto in 1930 at Lowell Observatory in Flagstaff. Here's how Pluto won - and lost - its planetary status.

Pluto may not be a planet any more, but you still have a chance to see the distant dwarf planet at one of Michigan's ...

“New Horizons shattered a major paradigm of planetary science,” says Alan Stern, the mission’s principal investigator. “Pluto ...

Feb. 18 marks the 95th anniversary of the discovery of our outermost planet-not-planet. Here's what to know about the short ...

Venus is now at its almost unbelievably brightest at a marvelous time when many other (though less radiant) planets and ...

Pluto was once the ninth planet of our solar system, until scientists reclassified it in 2006, sparking outrage and debate. But why was Pluto kicked out of the planetary club? The answer lies in a new ...