This striking satellite image reveals a giant, near-perfect cloud circle that formed in the heart of the Pacific ... on ...

Related: See all the best images of Earth from space A group of five barchan, or "horned," sand dunes can be seen in a zoomed-in version of the 2013 photo (see below). Over time, these arrowhead ...

Instead, it was a subtle but powerful reminder of the complex physics playing out in Earth’s atmosphere ... leave a clear middle—like this image of a circle of clouds. Scientists believe ...