posted on May, 30 2018 @ 06:47 AM
originally posted by: wildespace
There's simply no gravitational reason for billions of comets to come together and clump like that.
What's the gravitational reason for billions/trillions of rocks and asteroids coming together to form Earth?
The inner planets formed where it was warmer. The volatile materials (water, methane, etc) that formed the pre-solar system nebula would not easily
survive the inner warmth once the Sun lit up, so the materials that began clumpging together there was mostly rocky materials (asteroids), and those
mostly rocky asteroids were the raw materials that gravitationally came together to be the major component of the formation of the inner planets.
The volitile materials of the outer reaches of the nebula from which our solar system formed could still survive the emergence of the Sun, and the
warmth that came with it, because of their distance from the sun. Those volatile and icy gasses, along with the rocky materials also present in the
outer proto-planetary system, formed the icy comets that are prevalent in the outer solar system rather than forming mostly-rocky asteroids...
...And it was those icy comets and other raw materials that may have come together through gravity to form larger icy kuiper belt objects, just like
the more rocky raw materials of the inner solar system gravitationally came together to form the inner planets.
By the way, the gas giants of the outer solar system also formed beyond that "frost line" where the volatile gasses that formed together to make those
gas giants could still be present. It is the leftover materials -- the rocky asteroids left in the inner solar system and the icy stuff left in the
Kuiper belt and beyond -- that formed the rest of the solar system.
edit on 30/5/2018 by Soylent Green Is People because: (no reason