Since 2014, more than 20 such craters have exploded, pockmarking the remote landscape of northwestern Siberia’s Yamal and Gydan Peninsulas — the most recent of which was discovered in August.

A Merlin rocket engine exploded Sunday at SpaceX's test facilities in Central Texas. According to the company, no one was injured during the mishap, which damaged two bays in a Merlin engine test ...