NEWS - About 4 billion years ago, an asteroid slammed into Jupiter’s moon Ganymede, shifting the axis of the largest moon in the solar system. The asteroid was about 20 times larger than the one that ended the age of dinosaurs on Earth, causing one of the largest impacts with a visible footprint in the solar system.
“Jupiter’s moons Io, Europa, Ganymede and Callisto all have interesting features, but what caught my attention were the grooves on Ganymede,” said planetary scientist Hirata Naoyuki of Kobe University.
“We know that these features were formed by an asteroid impact about 4 billion years ago, but we weren’t sure how big the impact was and what impact it had on the moon,” Naoyuki said.
Ganymede is the largest moon in the solar system, even larger than the planet Mercury, and harbors an ocean of liquid water beneath its icy surface. The moon is tidally locked, meaning it always shows the same side to the planet in orbit.
Much of the surface is covered with concentric circles of grooves around a single point, leading researchers in the 1980s to conclude that the grooves were the result of a major impact event. .
Researchers have struggled with this and Hirata was the first to recognize the impact site, which is thought to be almost exactly on the meridian farthest from Jupiter. A similar impact event on Pluto caused the dwarf planet's axis of rotation to shift, and data from the New Horizons spacecraft suggests Ganymede may have undergone a similar change in orientation.
The asteroid that struck Ganymede was probably 300 kilometers (180 miles) across, or 20 times larger than the asteroid that hit Earth 65 million years ago, ending the age of the dinosaurs and creating craters 1,400 to 1,600 kilometers (750 to 1,000 miles) across.
"I want to understand the evolutionary origins of Ganymede and other Jupiter moons. The massive impact must have had a significant impact on their early evolution, but the thermal and structural effects of the impact have not been investigated at all. I believe that further research into the internal evolution of icy moons is possible," Hirata said.
Such a large impact would have changed the mass distribution and caused the rotation axis to shift to its current position. Ganymede is the final destination for ESA’s JUICE spacecraft. If all goes well, it will enter orbit in 2034 and conduct six months of observations to send back data that will help answer many questions.
Original research
Hirata, N. Giant impact on early Ganymede and its subsequent reorientation. Scientific Reports 14, 19982 (2024), DOI:10.1038/s41598-024-69914-2
“Jupiter’s moons Io, Europa, Ganymede and Callisto all have interesting features, but what caught my attention were the grooves on Ganymede,” said planetary scientist Hirata Naoyuki of Kobe University.
“We know that these features were formed by an asteroid impact about 4 billion years ago, but we weren’t sure how big the impact was and what impact it had on the moon,” Naoyuki said.
Ganymede is the largest moon in the solar system, even larger than the planet Mercury, and harbors an ocean of liquid water beneath its icy surface. The moon is tidally locked, meaning it always shows the same side to the planet in orbit.
Much of the surface is covered with concentric circles of grooves around a single point, leading researchers in the 1980s to conclude that the grooves were the result of a major impact event. .
Researchers have struggled with this and Hirata was the first to recognize the impact site, which is thought to be almost exactly on the meridian farthest from Jupiter. A similar impact event on Pluto caused the dwarf planet's axis of rotation to shift, and data from the New Horizons spacecraft suggests Ganymede may have undergone a similar change in orientation.
The asteroid that struck Ganymede was probably 300 kilometers (180 miles) across, or 20 times larger than the asteroid that hit Earth 65 million years ago, ending the age of the dinosaurs and creating craters 1,400 to 1,600 kilometers (750 to 1,000 miles) across.
"I want to understand the evolutionary origins of Ganymede and other Jupiter moons. The massive impact must have had a significant impact on their early evolution, but the thermal and structural effects of the impact have not been investigated at all. I believe that further research into the internal evolution of icy moons is possible," Hirata said.
Such a large impact would have changed the mass distribution and caused the rotation axis to shift to its current position. Ganymede is the final destination for ESA’s JUICE spacecraft. If all goes well, it will enter orbit in 2034 and conduct six months of observations to send back data that will help answer many questions.
Original research
Hirata, N. Giant impact on early Ganymede and its subsequent reorientation. Scientific Reports 14, 19982 (2024), DOI:10.1038/s41598-024-69914-2