an ethereal spectacle sometimes appears in the sky—clouds that shimmer with a ghostly blue-white light. These mysterious night-shining clouds, or noctilucent clouds, seem almost otherworldly ...

Named Eos after the Greek goddess of the dawn, the cloud of gas would appear huge in the night sky if visible to the naked eye. It measures roughly 40 moons in width and has a weight about 3,400 times ...

It's named Eos, after the Greek goddess of the dawn, and contains approximately 3,400 solar masses worth of gas.

The BBC's Sky at Night Magazine reports that, should we ever get to stargaze on Mars, we'd see two moons - Phobos and Deimos - instead of just one. We wouldn't see as many satellites either, making it ...