Geology of solar terrestrial planets billions of years ago in the cores of massive stars. These elements constituted only 0.6% of the material in the solar nebula. That is why the terrestrial planets could not grow very large and could not exert large pull on hydrogen and helium gas. Also, the faster collisions among particles close to the Sun were more destructive on average. Even if the terrestrial planets had had hydrogen and helium, the Sun would have heated the gases and caused them to escape. Hence, solar terrestrial planets such as Mercury, Venus, Earth, and Mars are dense small worlds composed mostly from 2%
Max Planck Institute for Solar System Research MPS is organised in three departments: In addition, since 2002 there is also an International Max Planck Research School. Subjects of research at the Institute are the various objects within the solar system. A major area of study concerns the Sun, its atmosphere, the interplanetary medium as influenced by the solar wind, as well as the impact of solar particles and radiation on the planets. The second area of research involves the interiors, surfaces, atmospheres, ionospheres, and magnetospheres of the planets and their moons, as well as of comets and asteroids. A further essential part of the activities at the