From tiny molecules to the vast expanse of the atmosphere, the blue sky is a testament to the elegance of the natural world. The next time you look up on a clear day, pause for a moment to ...

The expanse of sky is so wide, there's often more than one thing going on. Rain may darken the western rim while a fierce sun illuminates cloud towers in the center and a brilliant blue fills the ...

Look Up at the Sky Day, observed annually on April 14, invites us to pause, look up – and appreciate the vast expanse up there.