When did Giovanni Domenico Cassini first discover Iapetus?
Giovanni Domenico Cassini discovered Iapetus in October 1671. He observed the moon on the western side of Saturn during this initial sighting.
Questions about Iapetus (moon)
Short answers, pulled from the story.
Why does Iapetus have two distinct hemispheres with different colors?
The leading hemisphere displays dark colors with albedo values between 0.03 and 0.05 while the trailing hemisphere shines brightly with an albedo ranging from 0.5 to 0.6. This contrast results from ice sublimating preferentially from warmer dark zones and depositing onto colder bright poles over geologic time scales.
What is the height and length of the mountain range along the equator of Iapetus?
A massive mountain range stretches about 1300 kilometers long and rises more than 13 kilometers above surrounding plains along the equator. These peaks form some of the tallest mountains found anywhere in the Solar System.
Which spacecraft provided the closest images of Iapetus and when did it happen?
Cassini orbiter achieved its closest approach on the 10th of September 2007 at a minimum range of just 2600 kilometers. This final encounter approached from the night side before Cassini ceased further targeted flybys.
How far does Iapetus orbit from Saturn compared to other moons like Titan or Hyperion?
Iapetus orbits much farther from Saturn than its neighbor Titan does and remains 2.4 times farther out than Hyperion. It holds the most inclined orbital plane among regular satellites in the system.