Astronauts offer etiquette lessons to space tourists

Don't look directly at the Sun. Don't play with your grape juice. And don't hog prime viewing space at the windows. This was the advice several astronauts and space doctors gave to prospective space tourists on Tuesday More…

Mars images hint at recent climate swings

A dust layer sandwiched between layers of ice near Mars's north pole suggests the planet's climate has shifted dramatically in the past 100,000 years or so, reveal images recently obtained by NASA's Mars Reconnaissance Orbiter (MRO). More…