While the Earth and all other solar system objects formed from the same initial reservoir, the solar accretion disk, they have very different composition and structure. The processes at the origin of these differences remain largely unknown. They also controlled the composition of the raw materials from which life originated and the environmental conditions pertaining to the development of the first living organisms on Earth, and perhaps also elsewhere in the Solar System, or even further away among extrasolar planets. IPGP is one of very few institutions where scientists from different fields can work together towards deciphering the processes that shaped the Solar System, its planets and its habitability. For instance, remote sensing, orbital gravimetry and magnetic mapping are used to study the early geological evolution of terrestrial planets and the origin and history of atmospheres. Mineralogical, magnetic and isotopic properties of extra-terrestrial matter and Precambrian rocks are used to provide insights into the origin and early evolution of the Earth and its precursors. Many types of samples are studied: meteorites, and samples brought back to Earth by space missions such as lunar rocks, as well as ancient terrestrial rocks collected in the field or through deep drilling.
Five major questions in the field of Origins have been identified:
• Find out when and how the first solids and planets formed in the solar system and the processes that controlled their bulk chemical and isotopic composition, with a focus on the complex nucleosynthetic origin of the chemical elements found in the solar system.
• Elucidate the origin of moons and rings around planets and reconstructing the collisional history of terrestrial planets, with a special emphasis on the origin, internal structure and early evolution of our Moon.
• Determine the key parameters controlling planetary differentiation into a metallic core, a silicate mantle and a silicate crust: elucidating how the first oceans and the atmosphere formed on Earth and evolved over the early geological history.
• Figure out when and how the geodynamo, mantle convection and plate tectonics started on Earth, the consequences this entailed for surface conditions and why the evolution of other terrestrial planets was very different.
• Decipher the traces and causes of the major changes in Earth’s surface conditions during the Precambrian and identify the first traces of life or organic compounds.