The Earth and Other Solar-System Bodies

Abstract

Our knowledge of solar-system bodies, their formation and evolution, has tremendously improved over the past 50 years. The main reason is the advent of the space era and the in-situ exploration of planets, satellites and comets with flyby probes, orbiters, landers, and even rovers in the case of Mars. In addition, ground-based observations campaigns using large telescopes and an improved instrumentation have led to major discoveries, such as the detection of trans-neptunian objects. Numerical simulations have also been essential for understanding the dynamical history of solar-system bodies. In the future, planetology will face several challenges. The first open question is the formation scenario of the solar system, which looks very different from those of extra solar systems recently discovered. Will we find stellar systems comparable to ours, or is the solar system unique? To better constrain the formation scenario of the solar system, a special emphasis will be given to the study of primitive bodies, such as comets and trans-neptunian objects, which can be seen as remnants of the early stages of solar-system formation. Another challenging question is the search for life in the solar system. We have identified several niches where liquid water might have been probably present (the surface of Mars) or could presently exist (in the interiors of outer satellites). These environments will be favoured targets for space planetary exploration in the forthcoming decades.