#MERCURY'S #TAIL HAS #RETURNED: Space weather affects some planets more than others. It's really hard on Mercury. The solar wind scours Mercury's rocky surface at point-blank range, creating a "sodium tail" occasionally visible from Earth. David Marshall of Christ Church, Barbados, saw it on Dec. 20th:

"It's back! Mercury's sodium ion tail is approximately 1 degree long in this image and is expected to become more prominent over the next couple of days," says Marshall.

First predicted in the 1980s, Mercury’s tail was #discovered in #2001. It is a yellow-orange tail of sodium-rich gas more than 24 million kilometers long.

Mercury's tail brightens and dims as it orbits the #sun.

https://spaceweather.com/