Earth Atmosphere

From an average altitude of 400 kilometers above the surface of Earth, the brilliant shades of orange and red along our planet’s curving limb are often stunning. They also showcase an […]

Mega Chad

Lake Mega Chad

About 7,000 years ago, a vast lake spread hundreds of square kilometers across north-central Africa. Known to scientists as Lake Mega Chad, it covered more than 400,000 square kilometers at […]

Cloudy Sulawesi, Indonesia

Cloudy Sulawesi, Indonesia

The International Space Station was crossing over the equator when an astronaut looked east and took this photograph just after sunrise. The strip of land outlined by morning sunglint is the northern […]