Noctilucent clouds (NLCs), or polar mesospheric clouds, are breathtaking to see. And these are no ordinary clouds. They form in the highest part of our atmosphere, at an altitude of 80 kilometres.

The Martian forecast will almost always include a red sky but a recent panorama captured by NASA’s rover Perseverance shows what a blue sky would look like on the Red Planet.

This image shows the beauty of noctilucent clouds over Medicine Hat, Alta., in 2021. This is the best time of year to catch these electric-blue clouds, which appear after sunset and before sunrise.

One day last week we had a really blue sky. It had been awhile since we'd had one. Instead of blue, sometimes they were kind ...

People across Europe witnessed a mysterious glowing blue spiral in the night sky this week, and scientists say they think they know what caused the dazzling formation. The cloud-like spiral was ...