For decades, planetary scientists have suspected that ancient Mars was a much warmer, wetter environment than it is today, but estimates of just how much water Mars has lost since its formation vary widely.
Have you ever wondered how to become a scientist? Dr. Debra Fischer answers your question is this short video from the National Science Foundation.
Tuesday marks the 40th anniversary of the launch of NASA's Voyager 1 space probe. A companion spacecraft, Voyager 2, had launched a few weeks earlier on August 20, 1977.
At around 13 billion miles away, Voyager 1 has traveled the furthest distance from Earth for a human-created object. Voyager 2 has a record of its own - the longest continuously operating spacecraft.