Uranus' Moons Stun NASA With An Unexpected Dark Discovery By Hubble
For some context, Uranus' four largest moons -- Ariel, Umbriel, Titania, and Oberon -- are all tidally locked. This means that one side of each moon constantly faces the planet while the other side continually faces away from it. Scientists call the side facing the planet the "leading side" and the other, the "trailing side."
NASA thought that the leading side of Uranus' moon would be bright while the trailing side would be dark. Their thinking was based on the assumption that Uranus' magnetic environment (called the magnetosphere) hits the trailing side with charged particles, making that side dark.
However, while investigating the interactions between Uranus' magnetosphere and the four largest moons, they discovered that their brightness differed from initial assumptions. There was no evidence for darkening on the trailing side, but rich evidence for darkening on the leading side.
The leading and trailing sides had almost the same brightness level on Ariel and Umbriel. On Tatania and Oberon, the outer moons, the leading sides were even darker and redder than the trailing sides. This would mean, contrary to existing data, Uranus' magnetic environment might not actually interact mich with its large moons. NASA presented these findings at the 246th American Astronomical Society meeting, held this week in Anchorage, Alaska.
Scientists changing their understanding of the solar system as new information comes to light is quite common. We recently reported that a new finding revealed that the possibility of a collision between the Milky Way and the Andromeda Galaxy is unlikely, for example. The Hubble Space Telescope continues to amaze with its breathtaking images and discoveries and it likely won't be long before its upends another long held beleif.
