The giant hole appeared close to a forest some 30 kilometres from Yamal's biggest gas field Bovanenkovo. Experts are confident that a scientific explanation will be found for it and that it is not - as one web claim suggested - evidence 'of the arrival of a UFO craft' to the planet.
A report and footage highlighted by Zvezda TV says the dark colour of the crater indicates 'some temperature processes', without explaining more what they may mean. Others say that the darkening around the inner rim indicates its formation was accompanied by severe burning scorching the edges.
Some observers believe water or dry soil is seen falling into the cavity.