Night-shining ‘noctilucent’ clouds have crept south this summer
An uptick in atmospheric moisture may be fueling clouds that catch the sun’s rays after dark
![Noctilucent clouds](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2019/07/071219_cw_noctilucent-clouds_feat.jpg?fit=860%2C460&ssl=1)
SHINE ON Noctilucent clouds that catch sunlight after dark are showing up farther south than usual this year. Scientists are studying the upper atmosphere to figure out why.
Matthias Süßen/Wikimedia Commons (CC BY-SA 4.0)