text: Giant glaciers of ice may be lurking all over Mars, hidden from view by dust on the surface. That’s the surprising conclusion of a study that found that large amounts of ice were not just at the Martian poles, but likely towards the equator as well. It means that, if all ice were to be spread across the surface of Mars, the entire planet would be covered in more than 3.3ft (one metre). This image from Nasa's Mars Reconnaissance Orbiter shows that a thick layer of dust on Mars covers the glaciers, so they appear as the surface of the ground, but radar measurements show that there are glaciers composed of frozen water underneath the dust . The latest research was carried out by scientists at the Niels Bohr Institute at the University of Copenhagen and published in the journal Geophysical Research Letters. Evidence of water on Mars dates back to the Mariner 9 mission, which arrived in 1971. It revealed clues of water erosion in river beds and canyons as well as weather fronts and fogs. 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. Mars is currently in the middle of an ice age, so liquid water cannot exist on its surface at the present time. However, the planet seems to have been warmer and wetter in the past. In June 2013, Curiosity found powerful evidence that water good enough to drink once flowed on Mars. In September, the first scoop of soil analysed by Curiosity revealed that fine materials on the surface of the planet contain two per cent water by weight. Images from several Martian satellites had revealed the shape of glaciers just below the surface, and confirmed most were made of water-ice. And now the researchers have measured how big the glaciers are, and their similarity to glaciers on Earth. In total there is more than 150 billion cubic metres of ice on Mars, which could ‘cover the entire surface of Mars with 1.1 metres of ice,’ explained Dr Nanna Bjørnholt Karlsson at the Centre for Ice and Climate at the Niels Bohr Institute. She added that the ice closer to the Martian equator was ‘an important part of Mars’ water reservoir.’ There are thought to be thousands of glacier-like formations on the planet in both the northern and southern hemispheres. They are located on Mars between latitude 30.0 and 50.0 - equivalent to just south of Denmark’s location on Earth. Mars has belts of glaciers at its central latitudes - between the blue lines, in both the southern and northern hemispheres. A thick layer of dust covers the glaciers, so they appear as the surface of the ground, but radar measurements show that there are glaciers composed of frozen water underneath the dust . Using radar measurements (shown) from Nasa's Mars Reconnaissance Orbiter, researchers have been able to identify thousands of glacier-like formations on Mars. They can see how thick the ice is on the radar images . As the ice has not evaporated into space, the dust must be protecting it. If the ice were unprotected, it would evaporate and become water vapour, owing to the low atmospheric pressure on Mars. ‘We have looked at radar measurements spanning ten years back in time to see how thick the ice is and how it behaves,’ Dr Nanna Bjørnholt Karlsson explained. ‘A glacier is after all a big chunk of ice and it flows and gets a form that tells us something about how soft it is. ‘We then compared this with how glaciers on Earth behave and from that we have been able to make models for the ice flow.’ The latest research was carried out by scientists at the Niels Bohr Institute at the University of Copenhagen and published in the journal Geophysical Research Letters. They looked at how big the glaciers were, and also how similar they were to glaciers on Earth (one in Alaska shown) Nasa’s Mars Reconnaissance Orbiter, artist's illustration shown, launched on 12 August 2005. It entered Martian orbit on 10 March 2006, and continues to remain operational today. It is tasked with imaging the surface, and also monitors weather and surface conditions on Mars .
target: Danish scientists studied ice hidden under the surface of Mars .
  Dust is thought to be covering huge glaciers on the surface .
  And the researchers say there is more water-ice than anticipated .
  If spread out it would cover the surface in 3.6ft (1.1 metres) of ice .