What’s life without a little mystery? Three giant holes have suddenly appeared in the wastes of Siberia. The first emerged a couple weeks ago, a crater leading down a funnel to an icy lake below, its diameter nearly 262 feet. That prompted an inconclusive investigation. Now two more holes have appeared. They are smaller: one is about fifty feet across, the other almost fourteen feet.

Their depths are all around 230 feet. Loose earth around the rims of the holes seems to suggest an outward explosive force producing the pits. A consistent darkening pattern in the lip of the cavity could perhaps be scorch marks, evidence that there was a combustive element in their creation.

Investigating scientists have yet to explain these holes, but the Internet has plenty of theories. UFOs, the devil, missiles, meteors, and human mischief have all been put forth as explanations. The two most common postulations from the scientific community center around methane gas and the ice growths known as pingos.

The methane gas theory itself splits into two camps. Each relies on global warming softening Siberia’s permafrost, releasing methane gas toward the surface. That gas would presumably then pool under the frozen top layer. One camp believes that the growth of said methane pools could lead to the earth popping like a cork. The other camp believes that as the methane mixes with water, salt, and other gases, it spontaneously combusts, creating the chasms.

That explosive methane gas theory is of particular worry due to the large number of oil drills and pipelines in the area. Moreover, should pooling methane be the solution to this mystery, then that could be evidence that global warming is releasing methane from other deep reserves—specifically, the worlds oceans. Should that be true, it would only accelerate the pace of global warming and create an increasingly unstable environment.

The pingo theory posits that absorbed water freezes, which creates pressure, pushing it upwards through the earth and creating a hill or dome. When the ice melts and collapses, usually through solar radiation, it can leave behind a large pit.

Neither of those arguments are completely satisfying to researchers right now, and the investigation is ongoing. This may be a unique geological phenomena that has not occurred for 8,000 years, since it possibly formed the lakes that shaped the outer reaches of the Siberian landscape. At this point, answers will be slow in coming as scientists hope to get it right and not speak too soon. So we are left with only speculation.