A study suggests that a rare active volcano on Mars may be causing the planet to spin faster than expected. The discovery could explain Mars' quicker rotation and how the planet holds on to geologic heat longer than expected, leading scientists to rethink how small, rocky worlds cool and die. The study was published in the journal The Planetary Exploration Journal. The researchers identified a "negative mass anomaly" in the mantle beneath the Tharsis region, which may explain how the Tharathi region became so large and full of volcanoes. They also found that this less-dense material could shift mass inside Mars enough to influence the planet's spin. The findings could help scientists better understand how rocky planets cool and eventually die.