8 The Walnut Mystery
One of Saturn’s moons looks like a walnut. Along the equator of Iapetus snakes a line of peaks that gives the moon an unusual ridge. This feature is unique in the solar system and a complete mystery.
Recently, new simulations suggested that Iapetus once had its own ring, similar to those of Saturn. This theory fits the formation of the lunar range. At one point, the massive ring collapsed and fell to the moon’s surface. This was not a single event but rather several waves of material that rained down on the equator.
The model showed that if the first objects came in slowly and at a low angle, they would have skidded through the Moon’s icy crust and left deep tracks. Subsequent debris followed along the same path, piled up, and resulted in peaks reaching up to 20 kilometers (12.4 mi) high.
As mountain ranges go, it might not be the biggest. However, when measured in relation to the size of the world to which it belongs, the ridge is the largest range in the solar system.
7 Astronauts Warmed The Moon
In the 1970s, the first astronauts bounced over the lunar surface and made history. Then something strange happened. After the Apollo crews departed, the lunar temperature spiked by almost 2 degrees Celsius (3.6 °F).
For decades, this mystified NASA scientists. A dedicated team took eight years to track down 400 missing NASA tapes and to find and analyze temperature readings from mission logs that had been archived long ago. They studied the data, including photographs of where the men had walked.
In 2018, the results were released and revealed that the first 12 astronauts disturbed enough lunar dust to expose swaths of raw surface. They had been protected for billions of years by the dusty layer. But it took just six years for the scuffed spots to absorb enough solar radiation to raise the entire Moon’s surface temperature.
The temperature probes originally planted by the astronauts also confirmed that the heat started at the surface and not from inside the Moon. This fact was not known until the missing tapes were recovered and analyzed.