(Image: GETTY STOCK IMAGE • NASA )

The vast hole opened up several hundred kilometres across the area of about 80,000 square kilometres – but this feature remains a mystery to researchers.

Named as a “polynya”, this is usually found in coastal regions of Antarctica, but this hole is far from the edge where the ice is much thicker.

Kent Moore, a professor of physics at the University of Toronto, said: “In the depths of winter, for more than a month, we’ve had this area of open water. It’s just remarkable that this polynya went away for 40 years and then came back.”

(Image: NASA )

A smaller polynya was observed in the same area in the 1970s but the exact sale of that fissure was not recorded.

Many will suspect this having something to do with climate change, but scientists are yet to confirm.

The Weddell Sea polynya could force more changes in ice as the melting ice causes a localised temperature contrast between the ocean and atmosphere – which drives a convection current.

(Image: MEEREISPORTAL.DE )

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Some scientists speculate that the formation of the Weddell polynya is part of a cyclical process, though the details are unclear.

Researchers from the Princeton-based Southern Ocean Carbon and Climate Observations and Modelling (SOCCOM) group are conducting a study of the polynya that seeks to answer many of the questions.

Polynyas allow heat to escape the ocean, cooling the top layer of water as it becomes colder and denser – allowing more warm water to rise and keep the hole open.