Traces of water on the surface of Mars, found in recent years by NASA satellites, arose due to the melting of ice on the edges of large Martian craters after the fall of meteorites, according to an article published in the journal Geophysical Research Letters.
Scientists have found many hints that on Mars in ancient times there were rivers, lakes and entire oceans, comparable to our Arctic.
Many scientists to wonder how liquid water got to Mars and how it could have survived long enough to form a network of shallow but branched channels on the crater slopes.
David Weiss’s team noticed that all the channels and valleys of the "freshest" rivers are located where the melted fragments of soil and rocks that were thrown out when the asteroid collided with the surface of Mars were to fall.
As the calculations of geologists have shown, this heat should be enough to melt the significant reserves of ice under the surface of Mars and get enough water that can pierce these channels.
Martian：形容詞，火星的。例句：Water vapor has been detected in the martian atmosphere.（火星的大氣層裡，已檢測出水蒸氣。）
crater：名詞，隕石坑、火山口。例句：This crater （Lio）is a giant hollow with a diameter of 225 kilometers and a depth of about seven kilometers.（這隕石坑「里歐」是一個直徑225公里、深度約7公里的巨大凹洞。）
asteroid：名詞，小行星。例句：This crater （Lio） arose as a result of the fall of a large asteroid from 1.6 billion to three billion years ago.（這隕石坑「里歐」的出現，是16億年至30億年前，一顆巨大的小行星墜落的結果。）