From orbit, Emi Koussi’s dramatic caldera and lava-scarred slopes hint at its fiery past, while dried lakebeds and erosion ...

NASA's Perseverance rover has spotted an oddball rock in an ancient river channel on Mars. Deputy project scientist Katie Stack Morgan explains. Credit: NASA/JPL-Caltech/ASU/MSSS ...

For Americans planning cruise ship vacations this spring or summer, there could be reason to worry about more than rough seas, experts say.