Ceres has recently puzzled scientists worldwide as NASA’s Dawn mission revealed that the dwarf planet lacks the large impact craters a space body like itself should have. Nevertheless, the space body is dotted with smaller craters.
So, researchers believe that some mysterious geological process such as cryovolcanoes or the viscous bouncing back of the surface ice may provide and explanation.
Craters are to celestial bodies what scars are to people: they tell a story and can be reliable time keepers. Craters, however, can also pinpoint the type and composition of the rocks on a planet’s surface.
Scientists make use of craters to date a multitude of space bodies including moons and asteroids. One rule is that the older a thing is, the more craters it should have. Additionally, crater size can also tell a story on the planet’s past.
The 600-mile-wide Ceres, which is the largest known denizen of the Main Asteroid Belt, drew scientists’ attention mainly due to its size. It is larger than an asteroid but smaller than a planet, and was in the end classified as a dwarf planet, just like its remote cousin, Pluto.
Scientists believe that Ceres holds important clues to our solar system formation. And one first step in that direction is to study its craters. And because the dwarf planet is considered to be quite ancient it should have been scarred by gigantic craters.
Yet, this is not the case. Although computer models suggested that it should host at least 10 major craters, i.e. craters with a 250-mile-plus diameter and theoretical models based on asteroid Vesta data suggested at least six huge craters, no monster crater appeared in Dawn photos.
The largest impact crater on Ceres is Kerwan which is just 173-mile wide, and the next in line is Yalode with its 167-mile diameter. Additionally, smaller impact craters in the 62-to-93 mile bracket are “severely depleted,” as study authors put it.
According to a study published this week in Nature Communications, the phenomenon may have an explanation.
According to an older theory, Ceres was not born within the Main Belt, but it has somehow migrated there. Proponents of this theory based their hypothesis on ammoniated phyllosilicates found on Ceres. Yet, even if the theory holds water, Ceres was still supposed to have some large impact craters on its surface.
The latest study suggests that the rocky world once had monster impact craters but evidence somehow vanished in time. Though they are not sure, researchers speculate that one of the planet’s large basins, the 500-mile-wide Vendimia Planitia, is one such impact crater. Researchers believe that its flat appearance is the result of ice volcanoes filling the ancient the crater with their material.
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