The asteroid that collided with Ganymede, the largest moon of Jupiter, was 20 times larger than the one that caused the extinction of dinosaurs on Earth.
The catastrophic event occurred about 4 billion years ago. As a result of the impact, Ganymede changed its position so that the crater from the collision is now directed in the opposite direction from Jupiter.
Computer modeling showed that the diameter of the asteroid was about 300 kilometers. It crashed into the surface of Ganymede at an angle of 60-90 degrees. The impact created an initial crater up to 1600 kilometers wide, which was partially filled with rock fragments and dust ejected during the collision.
Dr. Naoyuki Hirata of Kobe University in Japan explains that the characteristic furrows on Ganymede’s surface have long been thought to be the remnants of multiple concentric rings formed by the giant asteroid’s impact. However, it was still unclear how strong the impact was and how it affected the Jovian moon.
In their study, published in Scientific Reports, Hirata describes how the center of the furrow system points almost directly in the direction opposite to Jupiter. This could have happened if the asteroid that hit Ganymede added extra weight to the impact zone, destabilizing the satellite and causing it to rotate on its axis.
The collision had dramatic consequences for Ganymede, whose diameter exceeds 4,800 kilometers, making it larger than Mercury. The «impact completely destroyed the original surface of the» satellite and affected its internal structure, where scientists believe a salt ocean is hidden.
Further evidence to confirm or refute Hirata’s theory may come from the probe Juice The European Space Agency’s Jupiter spacecraft, which traveled to Jupiter and its moons last year. As part of its mission, the spacecraft will search for sources of water and energy necessary for life on Jupiter’s moons.
Source: The Guardian, Phys
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