The protostar began to attract things with its gravitational pull as this was happening planetesimals or protoplanets were formed. Soon enough the protostar evolved into a star which is our sun and with a flare of solar wind most of the gas and dust of the first four planets were blown away leaving rocky earthy planets. However, the wind of the sun was much weaker towards the outer lengths of the solar system therefore most of the gas remained with the planetesimals forming the gaseous planets we know today. In its state of completion, the earth has only 1/318 of Jupiter's mass and 1/329,000 of the sun's mass. In the universe, the most abundant solid is Ice. This is just one of the few theories of how our solar system was formed this theory is known as the protoplanet theory. Other theories such as the nebular hypothesis and the encounter theories do not explain what is already knows of the solar system and are inaccurate.
As I have said before cosmology is the study of the universe as a whole. It concerns thing such as the shape, structure, origin, and fate of the universe. Unfortunately due to the lack of technology most of cosmology is theoretical. Conversely, a theory is a model based on existing evidence, theories in cosmology involve an extensive use of math. However, math just extends the logic of what is already known, but by applying what is know to a prediction you can then formulate theories. Currently, the most widely accepted theory on the formation of the universe is the Big Bang theory. The big bang theory states that the universe started out as a single object or space, which exploded between 10 and 20 billion years ago. Edwin Hubble with his theory that the universe is expanding supports evidence of this theory. He noticed that distance galaxies have a red shift meaning the wavelength in the light is shifting from a short wavelength to a long wavelength.
