SPACE — On October 25, 1671, Italian astronomer Giovanni Cassini discovered a new moon on Saturn. Iapetus was the second moon ever discovered orbiting Saturn, and the first of four moons Cassini discovered on the ringed planet.
About six years earlier, Dutch astronomer Christiaan Huygens had discovered Titan, Saturn’s largest moon. After Cassini discovered Iapetus, it also discovered the moons Rhea, Tethys, and Dione orbiting the ringed planet.
When Cassini first saw Iapetus, the moon appeared like a small dot on the western side of Saturn. He calculated its orbit and thought he would see it again on the east side of Saturn 39 days later. However, Iapetus was nowhere to be seen.
When it reappeared on the west side, Cassini realized that Iapetus must have one side that was darker than the other. This is believed to be the reason why it is difficult to see when the dark side is facing Earth.
Also Read: Today’s History: Cassini-Huygens Launches to Saturn and Titans
More than 300 years later, NASA sent a spacecraft called Cassini to Saturn. The spacecraft took some pretty amazing photos of Iapetus. Realizing that Iapetus was similar to yin-yang in the Chinese concept of balance, he was later nicknamed the Yin-Yang Moon. Source: Space.com
2023-10-25 12:44:00
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