A rare storm system over Titan's tropics help explain the region's unique liquid-carved landscape.
With dedication and good timing, amateur astronomers have helped track asteroids and search for planets. NASA is enlisting some for a moon observation mission.
Some mid-career professionals are moving forward by starting over.
Universities and the US government warned American students about the risks of travel in Mexico. But Cancún numbers are off only slightly.
The US will launch the Kepler spacecraft Friday to look for other Earths.
Conservation land in Mexico and a desalting plant in Arizona are at the center of a debate over the river.
Effect of natural drought cycle and climate change is restoration of the grasslands of centuries ago.