Strange structures discovered buried below the surface of Mars

An expedition to Mars has uncovered an intriguing structure buried beneath the planet's surface.

The structure have the appearance of large polygons underground, and could offer insight into the structure and make-up of the planet.

Analysis from the Chinese rover Zhurong has revealed the 16 structures, which experts are now analysing.

Zhurong is the first Chinese rover expedition to the Red Planet and is exploring Utopia Planitia, the largest impact crater on Mars.

Radar from the rover found the structures buried around 35 metres underground, and examined their appearance horizontally across 1.9 kilometres - the first time this has been done.

But what do the structures mean?

Well, experts think that they were formed as part of a freeze and thaw cycle which was also responsible for creating cracks in the terrain when it was at the surface.

Previously, evidence has suggested that floods in the basins more than 3 billion years ago would have displaced sediment.

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This combined with other thermal processes would have formed the structures.

There was also no evidence that the structures had been formed as a result of lava like some on Earth, for example the Giant's Causeway in Ireland.

This is all well and good, but what can we glean from this information?

It tells us that, at one point, Mars had not only an atmosphere, but a varied atmosphere which would have been responsible for the freeze and thaw process indicated by the structures.

Yes, that's right, looking at structures buried deep underground can help us to theorise about the contents of the atmosphere not just millions, but billions of years ago.

Isn't science just amazing?

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The study authors said: “Occurring at low latitudes (∼25° N), the polygonal terrain, which is interpreted as having most likely formed by thermal contraction cracking, makes a compelling case for the high obliquity of early Mars.

“The subsurface structure with the covering materials overlying the buried paleo-polygonal terrain suggests that there was a notable palaeoclimatic transformation some time thereafter.”

And, of course, the presence of water on Mars in the past also raises a lot of interesting questions about whether there has ever been life on the planet.

All the same, Mars is not the highest candidate for extraterrestrial life in the solar system.

That goes to Jupiter's moon Europa.

Some scientists think that beneath the moon's frozen surface is a deep and cold ocean of liquid water.

If this exists, it may not be an environment that distinct from that found in the deepest oceans on Earth where life, though thinly spread, is abundant.