BellaOnline Forums Education Astronomy Saturn's giant moon discovered 360 years ago today

On March 25, 1655 Christian Huygens discovered Saturn's biggest moon. It didn't get a name at the time, but nearly two centuries later got the very appropriate name of Titan. Huygens was a Dutch mathematician, astronomer, telescope-maker, diplomat, and all-around very clever person.

When NASA's Cassini mission went to Saturn to study the planet and its system of moons and rings, it took a passenger. It was the European Space Agency's lander called Huygens, which landed on Titan and took this picture.

Five fun facts about Titan . . .

1. It's the only Solar System moon with a substantial atmosphere.

2. Except for Earth, Titan is the only Solar System body with an atmosphere that's primarily nitrogen.

3. It rains on Titan - but the rain is liquid methane, not liquid water.

4. Rocks on Titan are made of frozen water - it's so cold that ice is as hard as rock.

5. There are surface lakes on Titan - made of liquid methane.

Click to find out more about Saturn's planet-sized moon.

Our moon is called the Moon because it was the only one humans knew about for thousands of years. None of the moons of the other planets are visible to the unaided eye. When Galileo discovered Jupiter's four largest moons with his telescope, the reaction ranged from greeting it as a major sensation to accusing him of fakery.

So moons were still something of a novelty when, several decades later, Huygens discovered a moon for Saturn. Being the only one, everybody just called it Saturn's moon. Nearly thirty years went by before Cassini discovered another moon for Saturn. Neither of them could have imagined that spacecraft bearing their names would actually go and visit Saturn and its moons. The tenth anniversary of the Huygens landing on Titan was earlier this year.

Space.com does lots of good infographics and here's one of them. It's about Saturn's big, big moon Titan.