Comparative planetology based on material physics
- How planets were formed -
by Shinji Karasawa
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　 The formation of the solar system cannot be explained by universal gravitation alone. Cosmic dust particles have an extremely weak gravitational force, and they adhere to other particles due to the short-range force at the contact point. As the planets get bigger, the universal gravitational force increases, and when they get closer, the gravitational pull of each other increases, and the impact of the collision increases. The planets initially grew greatly due to their close-range attachment. As the universal gravitational force increases, the energy of the collision increases.　 Therefore, a large collision occurs at the end of the formation of the planet.
However, when planets in the same orbit collide, the entire center of gravity changes and continues to move in orbit, so eventually the fragments of the planet scattered by the collision gather at the center of gravity with a low gravitational potential, and a large planet is formed. This scenario corresponds to "Giant Impact".　
　When a substance with a counterclockwise rotation component due to the rotation of the Sun collides with a planet, it as a whole gives the rotational force of rotation in the counterclockwise direction. Mercury is small in size but close to the Sun, so it is thought that it was affected by the material emitted by the Sun and the solar wind to slow down its rotation. In addition, Venus's rotation is in the direction of clockwise rotation, but when the solar wind collides head-on with the thick atmosphere of Venus, it is thought to have caused "Superrotation of Venus" and had the effect of changing the rotation to the clockwise direction. (May23, 2025)

YouTube:Oxidation of ultrafine iron powders by solid carbon dioxide　　
YouTube:The internal structure of the Earth explained from the viewpoint ofcondensed matter physics　
YouTube:Origins of meteorites　
YouTube:Asteroid belt remains debris of the planet that failed to become the second Sun　
Youtube:The birth of planets those are understood by condensed the matter physics　
[Click on the image to play the video. ]
[to Index] Chap.1 Introduction
Chap.2 Bonding through contact of fine particles　Chap.3 Accumulation of the solar nebula
Chap.4 Formation of planets　Chap.5 Birth of the Sun
Chap.6 Formation of the asteroid belt 　[Conclusion]
[Website of shinji karasawa]　 E-mail:[shinji-karasawa@kbh.biglobe.ne.jp]