Some five billion years ago, in a perfectly ordinary place in the galaxy, something happened. It might have been a supernova explosion pushing a lot of its heavy-element wreckage into a nearby cloud of hydrogen gas and interstellar dust. Or, it could have been the action of a passing star stirring up the cloud into a swirling mixture. Whatever the kick-start was, it pushed the cloud into action which eventually resulted in the birth of the solar system. The mixture grew hot and compressed under its own gravity. At its center, a pro to stellar object formed. It was young, hot, and glowing, but not yet a full star. Around it swirled a disk of the same material, which grew hotter and hotter as gravity and motion compressed the dust and rocks of the cloud together.
The hot young pro to star eventually “turned on” and began to fuse hydrogen to helium in its core. The Sun was born. The swirling hot disk was the cradle where Earth and its sister planets formed. It wasn’t the first time such a planetary system was formed. In fact, astronomers can see just this sort of thing happening. Elsewhere in the universe.
While the Sun grew in size and energy, beginning to ignite its nuclear fires, the hot disk slowly cooled. This took millions of years. During that time, the components of the disk began to freeze out into small dust-sized grains. Iron metal and compounds of silicon, magnesium, aluminium, and oxygen came out first in that fiery setting. Bits of these are preserved in chord rite meteorites, which are ancient materials from the solar nebula. Slowly these grains settled together and collected into clumps, then chunks, then boulders, and finally bodies called planet animals large enough to exert their own gravity.
~ Mahipal Vyas from Ojaank IAS Academy