Formation Of Solar System
(Muhammad Unza Farooqui, Karachi)
Many scientists think our solar
system formed from a giant, rotating cloud of gas and dust known as the solar
nebula. As the nebula collapsed because of its gravity, it spun faster and
flattened into a disk. Most of the material was pulled toward the center to form
the sun. Other particles within the disk collided and stuck together to form
asteroid-sized objects named as planetesimals, some of which combined to become
the asteroids, comets, moons and planets. The solar wind from the sun was so
powerful that it swept away most of the lighter elements, such as hydrogen and
helium, from the innermost planets, leaving behind mostly small, rocky worlds.
The solar wind was much weaker in the outer regions, however, resulting in gas
giants made up mostly of hydrogen and helium.