Two new craters were discovered in Siberia this week, and surely they have a logical scientific explanation.
At first glance, however, these giant holes in the earth look less like a natural occurrence, and more like leftover special effects from an apocalypse movie. Or giant robot footprints. Or evidence of the End of Times.
This week’s finds bring the total mysterious Siberian crater count to three. The first hole was discovered last week on the Yamal Peninsula—which means “the end of the world” in the local language, according to the Washington Post. The hole is between 160 and 260 feet wide and over 200 feet deep, and has a frozen lake at the bottom.
The two new holes are not as wide as that, but are still just as mystifying. Science-based hypotheses (as opposed to the alien invasion variety) about the origins of the craters abound, including meteorite collisions, sinkholes, drilling-related methane explosions, stray missiles, and global warming.
The latter is the most likely explanation, according to scientists who have visited the site.
The frigid Siberian landscape is mostly covered by ice and permafrost. But the 2012 and 2013 Yamal’s summers were relatively hot, according to Andrey Plekhanov, a senior researcher at the State Scientific Centre of Arctic Research, in an interview with the Siberian Times.
In permafrost landscapes, groundwater in deep, unfrozen ground can move upwards through a crack in the permafrost. When it hits the colder ground, it freezes into ice and expands, leading to a dome in the surface. (Here’s a helpful diagram of the process from the British Society for Geomorphology.)
Some geologists are speculating that if the Siberian permafrost melted rapidly over the past two summers, the craters could be evidence of these melted ice lakes. As Plekhanov puts it:
The theory was that the number of Yamal lakes formed because of exactly such natural process happening in the permafrost. Such kind of processes were taking place about 8,000 years ago. Perhaps they are repeating nowadays. If this theory is confirmed, we can say that we have witnessed a unique natural process that formed the unusual landscape of Yamal peninsula.
Or, you know, it could always be aliens.