Mars formed in record time, growing to its present size in a mere three million years, more quickly than scientists previously thought.
Its rapid formation could explain why the Red Planet is about one tenth the mass of Earth.
The study supports a 20-year-old theory that Mars remained small because it avoided collisions with planetary building material.
The new finding is published in the journal Nature.
In our early Solar System, well before planets had formed, a frisbee-shaped cloud of gas and dust encircled the Sun.
Scientists believe that the planets grew from material pulled together by electrostatic charges - the same force that's behind the "dust bunnies" under your bed.
These proto-planetary dust balls grew and grew until they formed what scientists term "embryo" planets.
These rocky masses were large enough to exert a considerable gravitational force on surrounding material,...
