Giant troughs that stretch across the asteroid Vesta may have formed after a fellow asteroid smacked into Vesta's south pole, researchers say. These findings add to evidence that, like Earth, Vesta is ...

Catherine Weitz, a senior scientist at the Planetary Science Institute in Tucson, Arizona, has reported new evidence for multiple, water-related geologic processes on Mars. She and her colleagues ...

Off the southern coast of Japan, the Philippine Sea Plate lies underneath the Japanese mainland. The locked tectonic plates threaten to unleash a catastrophic megathrust earthquake, likely within the ...

View of a Mars polar trough, approximately 20 kilometers across and a few hundred meters deep. The image shows a mound (orange dot) and a depression (blue dot) that are concentrically layered. Some of ...