In the frozen outskirts of the solar system, a reddish dwarf planet orbits in silence. Known as Sedna, it is so distant that one trip around the Sun takes more than 11,000 years. For much of that time ...

When he wasn't designing warships, John Ericsson was dreaming up solar technology. The Swedish American inventor, credited with the screw propeller and the first ironclad vessel in the U.S. Navy, ...