Final answer:
Astronomers now believe that the differences in composition among the planets reflect collision events in the early solar system.
Step-by-step explanation:
Astronomers now believe that the differences in composition among the planets reflect collision events in the early solar system.
According to recent studies, there were violent events soon after the early evolution of the solar system, involving substantial changes in the orbits of Jupiter and Saturn. These events would have caused scattering of asteroids into the inner solar system, leading to a period of intense bombardment. These collisions would have affected the composition of the planets, resulting in the differences in composition that we observe today.