Even setting aside the unproven hints of ancient oceans, the extent of the outflow channels suggests that a huge total volume of water existed on Mars in the past.

即使不考虑未经证实的古代海洋迹象，流出渠道的范围表明，过去火星上存在着大量的水资源。

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Since most planetary scientists believe that water is essential to life, the presence of jarosite means that one prerequisite for life was once present on Mars.

由于大多数行星科学家认为水是生命的基本要素，因此黄钾铁矾的存在意味着火星上曾经存在出现生命的先决条件之一。

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We were discussing the geological evidence of liquid water on Earth and Mars three to four billion years ago.

我们讨论了30到40亿年前地球和火星上液态水存在的地质证据。

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Mars landers and rovers were designed to look for signs of liquid water that may have flowed on Mars in the distant past.

VOA: special.2010.07.28

Scientists have previously established the existence of water on Mars in the form of ice at the poles and water vapor, and pointed to geological features that appear to have been carved by water ages ago.

CNN: Life on Mars?

"The results suggest that water was incorporated during the formation of Mars and that the planet was able to store water in its interior during the planet's differentiation, " Hauri said.

MSN: Scientists say parts of Mars interior are as wet as Earth's

Images taken by the orbiting NASA's Mars Global Surveyor spacecraft enabled scientists to detect changes in the walls of two craters in the southern hemisphere of Mars, apparently caused by the downhill flow of water in the past few years.

CNN: Life on Mars?