The high-tech system imaged the tiny droplets at the edges of clouds and found that there is a sharp transition between cloud and sky. The results may help scientists build better climate and ...

Grundy had spotted features in the haze on the edge – or “limb ... and a discrete fuzzy cloud seen against the sunlit surface above Krun Macula (I think) on the right,” he wrote.

Each year since the mid-1990s, as the sun has illuminated more and more of the northern hemisphere, the clouds have appeared brightest along the northernmost, newly sunlit edge. But bright clouds ...

These strange high-flying clouds at the edge of space — beguiling to scientists just two decades ago — are easy to observe from the station's orbit about 250 miles above Earth. "We have had so ...