Ganymede hit by massive asteroid, altering its axis

Ganymede, the largest moon in the solar system, experienced a significant impact from an ancient asteroid approximately 4 billion years ago. This asteroid was estimated to be 185 miles wide, striking Ganymede at a steep angle, resulting in a massive crater up to 1,000 miles wide. The impact altered Ganymede's axis, causing it to rotate such that the crater now faces away from Jupiter, the planet it orbits. This reorientation is supported by computer simulations conducted by Dr. Naoyuki Hirata, which suggest that the impact added weight to the moon's surface, destabilizing it. The collision not only reshaped Ganymede's surface but also likely affected its interior, which is believed to contain a subsurface saltwater ocean. The distinctive furrows observed on Ganymede's surface have been linked to this ancient impact, previously thought to be remnants of multiple concentric rings. The research highlights the complexity of Ganymede's geological history, shaped by billions of years of bombardment from celestial bodies. Further investigation into Ganymede's geological features and the implications of this impact is anticipated from the European Space Agency's Juice probe. This mission aims to explore the moon's surface and subsurface, searching for water and energy sources that could support life. The Juice spacecraft is equipped with advanced instruments to capture detailed images and analyze Ganymede's shape and gravity field, providing insights into the moon's past. Prof. Leigh Fletcher emphasized the importance of understanding the overlapping geological events on Ganymede's surface. The findings from the Juice mission could offer valuable evidence to support or challenge the impact and reorientation hypothesis, enhancing our understanding of Ganymede's evolution and its potential for harboring life.