Venus spins extraordinarily slowly and in the opposite direction to most planets — and new research suggests a violent ancient encounter may be to blame.
A primordial collision
Scientists propose that a chance encounter with a moon-sized impactor some 4.5 billion years ago could explain Venus's strange retrograde rotation, which sees the planet turn so slowly that a Venusian day is longer than its year.
Reconstructing the past
Understanding how Venus ended up so different from Earth — despite their similar size — helps scientists piece together the early history of the solar system and the forces that shaped the planets.
Source: ScienceDaily.