ESA's Mars Express orbiter discovers ice water deposits at the Red Planet's equator

Scientists operating Europe's Mars Express orbiter say it may have spotted huge ice water deposits below the surface of Mars.

It’s estimated that the deposits are around 3.7 kilometres thick, meaning that they could fill Earth's Red Sea if melted or cover the entirety of Mars in a layer of water about two metres deep.

The new findings suggest that Mars once looked very different to how it appears today, with glaciers, lakes, and river channels, according to scientists.

"We've seen evidence of glaciers, extinct glaciers which are no longer there, but also some glaciers covered with dust. Most of the water ice we've seen on Mars today is at higher latitudes, where the temperatures are colder and so the ice can be stable," said Colin Wilson, a project scientist at ESA.

"It's a testament to how much water there would have been on Mars in the past to amass piles of water ice several kilometres thick. That's a vast amount of water. So, we've seen the evidence of lots of water on the Martian surface in other places," Wilson added.

ESA’s Mars Express orbiter first confirmed the presence of ice on the Red Planet in 2004.

It discovered the deposits in 2007, but it wasn’t clear what they were made of -- perhaps giant accumulations of dust, volcanic ash or sediment.

In 2015, NASA also said Mars appears to have flowing streams of salty water.

"Today, we're revolutionising our understanding of this planet. Our rovers are finding that there's a lot more humidity in the air than we ever imagined," said Jim Green, NASA’s Director of Planetary Science, at a press conference.

Now, 15 years later, Mars Express’ new data suggests the deposits are actually layers of dust and ice.

The ice water is located at its equator, not at its poles, which