The solar system is a diverse environment from the small rocky worlds at its centre (including Earth), to the gas giants with their own systems of moons and the numerous minor bodies such as asteroids and comets. Each of these bodies offers different clues to the formation of the solar system. In recent years we have been able to observe planets orbiting distant stars. The development of more advanced techniques and sophisticated telescopes and satellites will lead to an increased understanding of distant solar systems.
The Sun is central to life on Earth. As the nearest star, the Sun has a special place in astronomy as detailed measurements are not possible for its distant cousins. Current projects have the capabilities to explore the physics of the Sun, from its exterior regions that impact directly on conditions on the Earth, down to the processes that take place at its centre. It is a keystone on which much of the knowledge of stellar structure and evolution is based. Furthermore the Sun’s variability is of crucial consideration for climate models of the Earth.
A big question for humanity, both from the standpoint of science and philosophy, is whether or not there is life elsewhere in the Universe. Over recent years a paradigm shift has occurred in the debate regarding the probability of life, and in particular whether benign earth-like conditions are required. Microbial life has been discovered on Earth which survives well in the most hostile and extreme of environments. The consensus now is that, where there is water, nutrients and an energy source such as our Sun, or from within a planet’s sub-surface, then the possibility for discovering life (past or present) is considerable. The obvious first place to search for extra-terrestrial life is within our own solar system. Possible examples include Mars that may have regions in its permafrost that could harbour microbial communities, and also in the subsurface water ocean of Jupiter’s moon, Europa. Beyond our own solar system, exoplanets may also harbour life.