Planetary Science and Cosmochemistry at the University of Manchester

我们试图了解我们太阳系的各种环境是如何形成和演化的，以及它们今天是如何运行的。我们研究到达地球表面的样品(例如陨石)或由太空任务带回来的样品。我们还使用对太阳系其他天体的观测，从中我们可以确定其组成，并推断它们的火山活动和撞击陨石坑的历史。我们将我们的数据与模型进行比较，例如模拟大气、小行星冷却和火山喷发的模型。这些模型基于我们用来理解我们星球的相同理念。因此，除了了解我们的太阳系，我们还测试了我们的想法，并深入了解了地球环境如何对自然和人为变化做出反应。包括地球在内的行星的组成是在45.6亿年前环绕着不断增长的太阳的尘埃和气体的圆盘中形成的。成团的尘埃颗粒被闪电加热成熔滴，迅速冷却：球粒。球粒的形成去除了被热能驱离的物种(“挥发物”，如水)。通过在实验室制作“球粒”并将它们与陨石样本进行比较，我们将了解圆盘的成分，并试图确定加热机制(闪电、冲击波、撞击)。第一批小行星--小行星--是由球粒陨石和其他颗粒形成的，其中一些从来不是热的。快速衰变的放射性加热了行星体，随着行星体冷却，它们被轰击，直到圆盘消散--这导致了更多的挥发性损失。通过研究来自这些行星的陨石，我们将追踪加热、冷却和撞击过程的历史，以了解行星的初始组成，表征形成早期太阳系的撞击，并了解放射性是否在盘中均匀分布，或者显示出在太阳系形成时来自附近恒星的证据。一些陨石含有丰富的挥发物。我们将了解它们的挥发性成分是如何演变的，并测试它们是否可能代表着一个补充行星的来源。我们还将测试漂浮在我们大气层中的微小尘埃颗粒，看看它们是否对另一个来源进行了采样，例如彗星。我们将研究微生物是否可以在一些陨石中的富碳物质上生存，以及这种材料是否可以作为地球以外生命的燃料。自从行星形成以来，它们的地壳受到了撞击、火山活动和水流的影响。撞击提供了一种可以改变岩石结构的热源--月球上的一些神秘岩石提供了机会来研究这种情况是如何发生的，并了解整个太阳系行星壳演化的一个主要过程。月球火山活动在火山火山碎屑沉积中很明显，火山火山碎屑沉积现在覆盖着火山喷口周围的表面。利用这些火山中心的图像，以及从月球带回的火山岩结构，我们将发现这些物质从月球内部爆炸出来的速度有多快。由于膨胀的气体为这种喷发提供动力，这反过来将提供对月球内部挥发物浓度的洞察。我们将检查最近发现的一块火星陨石，它似乎是由撞击组装而成的不同时代的多个碎片。由此，我们将了解火星表面的成分如何随着时间的推移而变化，以及这是如何影响其大气的。行星大气提供了一个令人兴奋的机会来测试我们用来了解我们自己的天气和气候的想法。火星表面显示出40亿年前的痕迹，当时它的气候与地球非常相似，我们将研究云如何在这种环境中形成并导致降水。在土星上，我们将通过模拟围绕其北极的六边形云结构的形成来测试我们对行星自转如何与其大气相互作用的理解。

We seek to understand how our solar system's diverse environments formed and evolved, and how they operate today. We study samples that arrived at the Earth's surface (e.g. meteorites) or were brought back by space missions. We also use observations from missions to other bodies in our solar system, from which we can determine compositions and infer their history of volcanic activity and impact cratering. We compare our data to models, such as those that simulate atmospheres, the cooling of asteroids and volcanic eruptions. These models are based on the same ideas we use to understand our planet. So as well as learning about our solar system, we test our ideas and gain insight into how the Earth's environment responds to natural and man-made changes.The compositions of the planets, including the Earth, were set as they formed in a disk of dust and gas that circled the growing sun 4.56 billion years ago. Clumps of dust grains were flash-heated into melt droplets that rapidly cooled: chondrules. Chondrule formation removed species that are driven off by heat ("volatiles", like water). By making "chondrules" in the lab and comparing them to meteorite samples we will understand the composition of the disk and try to identify the heating mechanism (lightning, shock waves, impacts). The first asteroids - planetesimals - were formed from chondrules and other grains, some of which had never been hot. Fast-decaying radioactivity heated planetesimals, and as planetesimals cooled they were bombarded until the disk had dissipated - this led to more volatile loss. By studying meteorites from these planetesimals we will track the history of heating and cooling and impact processing to understand the starting compositions of planets, to characterise the impacts that shaped the early solar system, and to learn whether radioactivity was equally distributed in the disk or shows evidence of having been introduced from a nearby star as the solar system was forming.Some meteorites are rich in volatiles. We will learn how their volatile content evolved, and test whether they may represent a source that replenished the planets. We will also test minute particles of dust that float down through our atmosphere to see if they sample another source, such as comets. We will study whether microbes can live on carbon-rich material in some meteorites, and so whether this material could serve as fuel for life beyond Earth. Since the planets formed, their crusts have been modified by impacts, by volcanic activity, and by water flows. Impacts provide a source of heat that can change the structures of rocks - some enigmatic rocks on the Moon offer the chance to study how this occurs and learn about a major process in the evolution of planetary crusts across the solar system. Lunar volcanic activity is evident in the volcanic pyroclastic deposits that now drape the surface around volcanic vents. Using images of these volcanic centres, and the structure of volcanic rocks brought back from the Moon, we will find out how rapidly the material was blasted out of the lunar interior. Since expanding gases power such eruptions, this in turn will provide insights into the concentration of volatiles inside the Moon. We will examine a recently discovered Martian meteorite that appears to be multiple fragments of different ages assembled by an impact. From this we will learn how the composition of the Martian surface has changed over time, and how this has affected its atmosphere. Planetary atmospheres provide an exciting opportunity to test the ideas we use to understand our own weather and climate. The Martian surface shows traces of a time 4 billion years ago when it had a climate very like the Earth, we will study how clouds would form and lead to precipitation in this environment. On Saturn, we will test our understanding of how a planet's spin interacts with its atmosphere by modelling the formation of hexagonal cloud structures around its North Pole.