SOLAR SYSTEM

Detailed explanation-1: -Within the solar nebula, scientists believe that dust and ice particles embedded in the gas moved, occasionally colliding and clumping together. Through this process, called “accretion, ‘’ these microscopic particles formed larger bodies that eventually became planetesimals with sizes up to a few kilometers across.

Detailed explanation-2: -According to the planetesimal hypothesis, when a planetary system is forming, there is a protoplanetary disk with materials from the nebulae from which the system came. This material is gradually pulled together by gravity to form small chunks. These chunks get larger and larger until they form planetesimals.

Detailed explanation-3: -Asteroids and comets are leftover planetesimals from the time of formation of our own solar system. The formation of km-sized or larger planetesimals remains an open problem in planet formation theories. Once objects are larger than  10 km, gravity helps these objects grow into planets.

Detailed explanation-4: -The dust particles were brought together by the forces of drag to form clumps of rock that grew into “planetesimals” tens to hundreds of miles across, and then to Mars-sized “protoplanets” by colliding with each other. Earth grew to its final size through one last major collision with another Mars-sized object.

Detailed explanation-5: -Jovian Planet Formation Thus, the planetesimals that formed in the outer solar system are composed primarily of hydrogen compounds with traces of rock and metal. Hydrogen and helium do not condense in the solar nebula, and are rather abundant in the large orbits of objects in the outer solar system.