There are many large asteroids in our solar system, and one called Vesta is the second largest of them all. Vesta has a diameter of about 330 miles. It’s located between the orbits of Mars and Jupiter. NASA has previously investigated Vesta with a program called Dawn that launched in 2007.

The mission’s goal was to study Vesta and Ceres, which are two out of a trio of known protoplanets in the asteroid belt. Vesta has rock in its crust and mantle along with an iron core. Its size and the fact that it has a crust, mantle, and core lumps into a group known as planetesimals. Scientists believe planetesimals are building blocks that planets, like Earth, originate from.

By studying Vesta, scientists can window into the very early stages of rocky planets like our own. Scientists never propose new theories on some of the surface features of Vesta. One of the big questions scientists wanted to answer was what caused the formation of large troughs seen around the asteroid’s equator.

Those troughs are circular and go around two massive impact basins known as Rheasilvia and Veneneia. Both impact basins are believed to have formed at the same time by impact events. The research showed that the troughs and basins have a similar number of craters of various sizes, indicating they are of a similar age.

The new theory suggests the troughs are something known as fault-bounded valleys. Scientists say each of the valleys has a distinct scarp on each other sides, indicating sliding of a block of rock. The team says rock can crack apart and form troughs as seen near the equator, which is something that hadn’t been previously considered. Project scientists say calculations indicate gravity on the asteroid is too low to induce stresses for rock sliding to occur at shallow depths. Therefore, the physics indicates rocks there cracked apart.