The featuring is hovering over a volcano on the Martian surface. But it does not appear to be related to volcanic activity, instead is a water ice cloud being pushed around by the volcano.
That did not stop many speculating that the images showed a huge fire burning on the planet, despite that being technically impossible. And some even went to far as to suggest that the activity might be linked to alien life, with one newspaper suggesting the evidence could be getting hidden by Nasa.
But the actual explanation is much cooler: it's not hot, but very cold indeed. Water ice clouds condense over the summit of the volcano, known as Asia Mons, and can be spotted spreading across the surface.
The images were collected by the European Space Agency's Mars Express craft. They were first spotted in late September and have been tracked throughout October, allowing for hundreds of pictures.
The white cloud stretches 1,500km over the surface of the planet – far bigger than the volcano itself – making it easy to see in images sent back from the spacecraft.
Usually, the clouds disappear around this kind of year. Mars had its winter solstice on 16 October, and the clouds usually go before that.
But a water ice cloud in this region has occurred at a similar time of year before, scientists say.
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