Scientists have discovered a gigantic volcano on Mars near the planet’s equator that remained unnoticed for decades, according to newly published research. The huge volcano was found in the Red Planet’s eastern Tharsis volcanic province, along with what researchers interpret to be a large sheet of buried glacial ice beneath the Martian surface. The discovery came as a surprise, partly because orbital spacecraft have photographed this region of Mars since the early 1970s. Hidden in plain sight now for decades, the giant volcano, which has undergone extensive erosion over time, somehow remained unnoticed. The feature has been given the temporary...