In fact, the hole was thought to be a hoax until new footage of it taken by Russian engineer Konstantin Nikolaev was posted online this week. Since then, a number of theories about the hole's appearance have emerged, including, but not limited to: a sinkhole; impact from a meteorite; an underground gas explosion spawned from the area's gas-rich reserves; and a geological formation known as a hydrolaccolith, or pingo.
The only two details scientists from Russia's Emergencies Ministry have confirmed so far is that a large amount of soil seems to have been "thrown" out of the hole and that the crater likely didn't form from a meteorite striking the earth.
"We can definitely say that it is not a meteorite. No details yet," a spokesperson from the Yamal branch of Russia's Emergencies Ministry told the Siberian Times.
Two theories have emerged as the front-runners for a possible explanation on the site's formation. The first of which comes from Anna Kurchatova from the Sub-Arctic Scientific Research Center.
Kurchatova believes that the hole was formed by a explosion triggered by a volatile combination of water, gas, and salt. Kurchatova told the Siberian TImes that global warming likely caused a rapid melt of ice packed full of gas, releasing the gas in an action akin to "popping a champagne bottle cork," ultimately creating the crater.
The other theory comes by way of Dr. Chris Fogwill, a polar scientist at the University of New South Wales. Fogwill told the Sydney Morning Herald that he believes the crater formed due to a geological formation called a hydrolacccolith, or pingo. According to Fogwill, a pingo is just a large chunk of ice that forms into a small hillside. Eventually, that ice can push through the earth, and when it melts, leave behind a large hole, similar to the one discovered in Siberia.
“This is obviously a very extreme version of that, and if there’s been any interaction with the gas in the area, that is a question that could only be answered by going there,” Dr. Fogwill told the Sydney Morning Herald.
Like Kurchatova's explanation, Fogwill says that global warming likely contributed to the rapid melt of the pingo's hole, exposing it.
“We’re seeing much more activity in permafrost areas than we’ve seen in the historical past. A lot of this relates to this high degree of warming around these high arctic areas which are experiencing some of the highest rates of warming on earth,” Dr. Fogwill said.
More answers are expected from a team of Russian scientists dispatched to the area Wednesday. But until their reports come in, people will continue to wonder just what caused the unexplained phenomenon.