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%
The Science of Aliens possibilities for alien life. The second section explores the variety of life on Earth and the extreme conditions in which it can survive. It looks at recent missions to moons and planets in the Solar System and what they can tell us about alien life before going on to examine some extra-solar planets. The next section presents two fictional planets, Aurelia and Blue Moon and their ecosystems as imagined by scientists. These are used to explore the factors and parameters governing life on other planets and are presented as two large interactive landscapes. The exhibition concludes by looking at the