Scientists have discovered the largest impact crater in the Solar system. Giant trail, located on Jupiter’s moon Ganymede, reaches a diameter of 7800 miles. The previous record, equal to 3,800 kilometers, belonged to another crater Valhalla on Jupiter’s moon Callisto. The article, which describes the discovery of Japanese scientists from Kobe University, published in the journal Icarus.
the Researchers found that the grooves on Ganymede, which is the oldest geological structures on the satellite, form a series of concentric rings, looking like a trail from the impact of a large object. Previously it was thought that the furrows which constitute the depressions with sharp edges, arose as a result of multiple collisions when the lithosphere of Ganymede was more subtle and not as strong as it is now.
Planetary scientists have analyzed a series of satellite images taken by the probe Voyager in 1979 and Galileo Orbiter to Jupiter, which studied the planet and its moon. Ganymede has two types of surfaces: light and dark areas. The dark area in contrast to the light has many craters, indicating its older age. The dark zone also contains furrows, over which is formed the craters. The researchers caused the depression to the map and found that they are not scattered randomly, but form a circular ruffle. The results of computer simulation showed that this structure had to be caused by the fall of an asteroid with a diameter of 150 kilometers, which crashed into the surface at a speed of about 20 kilometers per second.
According to scientists, a catastrophic event occurred about four billion years ago. However, scientists want to obtain more information which will conclusively establish the cause of the anomalous structure. For example, the probe “Juno” needs to fix the gravity anomaly in the area of the alleged crater. Also, another probe — the Jupiter Icy Moon Explorer — will be launched in 2022 for a detailed study of the moons of Jupiter.