Elon Musk Outlines His Plan to Colonize Mars

Elon Musk outlined his plan to colonize Mars before a highly receptive crowd at the International Astronomical Congress in Mexico this week. The cleantech visionary framed the future settlement as the only eventual choice for humans in a world facing major environmental threats.

Is High-Speed Train Travel Worth the Investment?

With all the pros of high-speed trains, from fast travel times to limiting pollution, people often wonder why they aren’t even more widespread. But the answer to that question is complex, and varies largely from region to region.