Giant crater mystery
A huge hole has been spotted in the Russian Arctic by a TV crew flying overhead. Despite speculation that the 50-metre crater might have been caused by weapons testing or even a UFO, scientists think there’s a perfectly natural explanation. They say high temperatures over the summer must have caused an eruption of methane gas below the thawing permafrost (frozen soil), scattering blocks of ice and soil for hundreds of metres. It’s the 17th giant crater to have been spotted in the last six years.