A look back over centuries at man's attempt to uncover information about the 'Red Planet.'Sources: NASA, American Museum of Natural History, and Scientific American
George Ferris, whose 154th birthday is celebrated with a Valentine's Day-themed Google Doodle, didn't just come up with a new amusement park ride; he provided an opportunity for physics teachers to come up with truly terrifying scenarios.
After 50 years of missions to Mars, scientists are unlocking some of the mysteries surrounding a planet that has captivated mankind for millenniums. Will humans ever leave a boot print on Mars?
First test: See how you do with this book.