It tipped the balance. Massive volcanic heat beneath the moon’s surface altered its density and shifted it off its axis about three billion years back, according to new research. Scientists argue that a six-degree shift moved hydrogen deposits away from its original poles — a change they compare to Earth’s North Pole moving to Greenland. The “total pole wander” shows that lunar water dates to before the volcanic eruptions, possibly the early years of the solar system. Researchers hope this discovery will lead to further polar ice exploration on Earth’s natural satellite.