Noctilucent Cloud Season Has Begun

May 20, 2020: NASA’s AIM spacecraft has detected a noctilucent cloud (NLC) inside the Arctic Circle–the first of the 2020 summer season. It is the blue puff in this satellite image of the North Pole:

The detection on May 17th marks one of the earliest starts in the 14 year history of the spacecraft. “In previous years, we have seen the first NLCs appear between May 15th and May 27th,” says Cora Randall, a member of the AIM science team at the University of Colorado. “Only once, in 2013 (May 15th), has the northern season started earlier than this.”

NLCs are Earth’s highest clouds. Seeded by meteoroids, they float at the edge of space more than 80 km above the ground. The clouds form when summertime wisps of water vapor rise up to the mesosphere, allowing water to crystallize around specks of meteor smoke. Last summer, they spread as…