There are two different pronunciations of Iapetus: Eee-a-Pa-tus or I-a-PA-tus. Either of these pronunciations are accepted.
|Discovered By:||G.D. Cassini October 25, 1671|
|Mass:||1.81 × 10^21 kg (2.5% Moon)|
|Orbit Distance:||3,560,851 km|
|Orbit Length:||79.3 days|
|Surface Temperature:||-143 to -183 °C|
Iapetus is one of the four moons of Saturn that were discovered in 1672 by Giovanni Cassini.
Iapetus was a bit difficult to find due to the dark and light that contrasted and hid the moon for many years.
Iapetus is tidally locked to Saturn, which means it keeps the same face turned toward Saturn and the same opposite face away from Saturn.
The unusual positioning of Iapetus kept it in the shadow, only allowing the bright side to be seen from Earth when it traveled on Saturn’s west side.
The most contrasting feature about Iapetus is that the side facing Saturn is brilliantly light, whereas the side facing away is coal black.
Cassini originally named the four moons as part of the “Sidera Lodoicea” or “Stars of Louis” in honor of King Louis XIV. However, not too many people liked the names and they were referred to in their numerical form based on their distance to Saturn.
Almost 200 years later, Williams Herschel’s son, John Herschel, suggested that the 4 moons be named after the mythological Greek Titans and their families (Saturn to the Romans).
Iapetus in Greek mythology is the son of Gaia and Uranus and the father of Prometheus and Atlas.
Since Prometheus was supposed to have given fire to mankind, Iapetus is considered to be the father of the human race. The density of Iapetus is so low that it is just a bit more than liquid water.
Scientists believe that the moon is made up of mostly water and about ¼ rock. Iapetus also has a weird walnut-shape with a center that bulges and poles that are squashed.
The shape is an indicator that the moon has an odd rotation, once every ten hours as compared to the orbit which takes 79 days to complete a revolution.
It’s believed that early in the life of this moon it was rapidly spinning and a thick crust could have frozen over its surface.
Over many years, the moon began to slow down in its spin and became tidally locked.
Iapetus is Saturn’s third-largest moon, with a diameter of 914 mi/1,471.2 km. Around its equator it has a chain of high mountains that stretch over halfway around it for over 800 mi/1,300 km.
It has mountain peaks that reach over 12 mi/20 km which make them some of the highest mountains in our solar system.