Ganymede’s surface is a bit of a puzzle for planetary scientists. About two-thirds of its surface is covered in lighter terrain, while the remainder is darker. Both types of terrain are ancient, with the lighter portion being slightly younger. The two types of terrain are spread around the moon, and the darker terrain contains concurrent furrows.
For the most part, scientists think that the furrows were caused by tectonic activity, possibly related to tidal heating as the moon went through unstable orbital resonances in the past.
But a new study says that a massive impact might be responsible for all those furrows.
It seems almost certain that an asteroid impact wiped out the dinosaurs. But only almost. Another competing theory won’t completely go away: the extinction-by-volcano theory.
A new study from the UK piles more evidence on the asteroid side of the debate, while adding a new volcanic twist. These researchers say that volcanic activity actually helped life recover from the asteroid strike.
Astronomers think they know how Uranus got flipped onto its side. According to detailed computer simulations, a body about twice the size of Earth slammed into Uranus between 3 to 4 billion years ago. The impact created an oddity in our Solar System: the only planet that rotates on its side.
A study explaining these findings was presented at the American Geophysical Union’s (AGU) Fall Meeting in Washington DC held between December 10th to 14th. It’s led by Jacob Kegerreis, a researcher at Durham University. It builds on previous studies pointing to an impact as the cause of Uranus’ unique orientation. Taken altogether, we’re getting a clearer picture of why Uranus rotates on its side compared to the other planets in our Solar System. The impact also explains why Uranus is unique in other ways. Continue reading “Something Twice the Size of Earth Slammed into Uranus and Knocked it Over on its Side”