Noctilucent clouds, Earth's highest clouds, shine blue in the twilight sky from late May to August in the northern hemisphere ...

Jumping back in time, Thuban was positioned as a North Star some 4,700 years ago, as early civilizations thrived in ...

In photos The details in this photograph include the airglow of the atmosphere dividing Earth from space — yellow-green at an ...

A little over 240 years ago, birds were the only things that could fly above the ground untethered without eventually falling ...

We've even been asked if you could run solar cells during the long lunar night on reflected earthlight, so we decided to ...

A little over 240 years ago, birds were the only things that could fly above the ground untethered without eventually falling ...