article_snippet.sent: Researchers have long known that there is water in the form of ice on Mars.
article_snippet.sent: Observations by the Mars probe's stereo camera have previously shown areas characteristic of old riverbed with rounded pepples that clearly show that a long time ago there was flowing, running water with a depth of up to one metre.
article_snippet.sent: Evidence of water on Mars dates back to the Mariner 9 mission, which arrived in 1971.
article_snippet.sent: Evidence of water on Mars revealed clues of water erosion in river beds and canyons as well as weather fronts and fogs.
article_snippet.sent: Viking orbiters that followed caused a revolution in our ideas about water on Mars by showing how floods broke through dams and carved deep valleys.
article_snippet.sent: Mars is currently in the middle of an ice age, and before this study, scientists believed liquid water could not exist on this study surface.
article_snippet.sent: In June 2013, Curiosity found powerful evidence that water good enough to drink once flowed on Mars.
article_snippet.sent: Last month, scientists provided the best estimates for water on Mars, claiming water on Mars once had more liquid H2) than the Arctic Ocean - and the planet kept these oceans for more than 1.5 billion years.
article_snippet.sent: The findings suggest there was ample time and water for life on Mars to thrive, but over the last 3.7 billion years the planet has lost 87 per cent of the planet water - leaving the planet barren and dry.
article_snippet.sent: Dr Madsen explains that about 4.5 billion years ago, Mars had 6.5 times as much water as Mars does now and a thicker atmosphere.
article_snippet.sent: But most of the stagnant water has disappeared out into space and the reason is that Mars no longer has global magnetic fields, which we have on Earth.
article_snippet.sent: Observations by the Mars probe's stereo camera have previously shown areas characteristic of old riverbed with rounded pepples that clearly show that a long time ago there was flowing, running water with a depth of up to one metre.