LAST week, the National Aeronautics and Space Administration (Nasa, 美國太空總署) of the United States announced an exciting discovery. They have found liquid water on Mars (火星)!
Whether there is water on the Red Planet has been a hot issue over the last few decades. In the past, some even claimed that the lines on Mars̕ surface looked like canals. But all water has been found frozen so far. In the past few years, NASA has been using a piece of special equipment on a spacecraft that stays in orbiting Mars to examine the chemical compositions of its surface, rocks and soil. After some analysis of the spectrum, they now conclude that there is salt water trickling on its surface.
Since flowing water has been discovered, people naturally ask: does that mean there is life on Mars? It is a difficult question to answer. There is no clear evidence to prove that at the present moment. Sending a spacecraft to Mars to investigate may not help, as we may have brought micro organisms from Earth to Mars!