Planetary Origins and Evolution at Imperial (2019-2022)

点击翻译按钮获取中文摘要

How do stars and planetary systems develop and is life unique to our planet? This is one of the most fundamental of questions in science and has deeply profound implications for our place in the cosmos. It is thus a key scientific challenge set by the Science and Technology Facilities Council. Our planet formed 4.5 billion years ago along with the Sun and the other planets and minor bodies in our Solar System. Only by understanding the details of how our Solar System formed can we hope to find an answer.We now know how stars and planetary systems form in general. We know that stars form by the collapse of interstellar clouds of dust and gas, and planets are constructed in disks of dust and gas surrounding these young stars. There is, however, much we don't know about how our Solar System formed. Why, for example, are all the planets so different? Why is Venus an inferno, Mars a frozen rock, and Earth a haven for life? The answer lies in events that predated the assembly of the planets. Our research program focuses on answering key outstanding questions in this early history of the Solar System.The source of presolar dust provides a context to our solar system. From what types of star was dust derived and is this mixture typical of other planetary systems? Some of this dust still remains preserved within ancient meteorites and reveals that at least 30 stars produced building blocks for our planets. We aim to sample many more stars by looking for interstellar dust preserved on the Earth's surface within sediments accumulated throughout our planet's history. This will provide a full ingredient list for planetary systems, not just our own.How planetary materials changed after the dust was assembled into larger bodies is crucial in making planets that are suitable for life. Our research will examine whether primitive planetesimals, the early forerunners of planets, melted and mixed internally by examining the evidence for early magnetic fields within meteorites. Our research will evaluate whether ancient magnetic traces already found in meteorite minerals are reliable indicators of the dynamos of metallic cores.Volatile constituents are vital to life but easily lost by heating and they differ greatly in abundance between planets in our solar system. Our research focuses on the volatile budgets of the terrestrial planets, to identify the source of the volatiles and determine when they were added. For this, the research examines the isotopes of selenium and tellurium and is made possible by technology and method advances that will be pioneered in the study. As such, the work will help us understand how planets acquire the ingredients essential to the formation life.Large quantities of volatiles, organic matter and energy, were delivered to the terrestrial planets in a prolonged period of intense bombardment in the early solar system, which likely had a profound influence on the emergence and evolution of life. Large craters that scar the Moon, Mars, Venus and large asteroids provide a record of this bombardment, but one that is challenging to decode. By simulating large crater formation using advanced numerical models, we aim to link observed crater populations to the impactors that formed them and constrain the timing and source of their delivery to the inner solar system.Finally, what constitutes a planet "suitable for life"? To date only Earth is known to have living things. Whilst the search for life on Mars continues, many believe that living organisms are more likely within the ice-covered oceans of the moons of Jupiter and Saturn. Our research will focus on recognizing the molecular signature of life within the atmospheres and outflows from icy-moons using experiments and world-leading analytical techniques. This research could provide the first convincing evidence for life beyond Earth and widen our view of the right kind of planet.