The origin and evolution of the terrestrial planets

Lead Research Organisation: The Natural History Museum
Department Name: Earth Sciences

Abstract

The Solar System we see today, comprised of a central star orbited by planets, formed from a cloud of dust and gas that collapsed over 4.5 billion years ago. We can learn about the early stages of the Solar System's history by studying meteorites - samples of rocky asteroids (and possibly comets) whose contents provide us with snapshots of the events they have experienced. Some asteroids have remained rather dormant throughout their history, and preserve the very materials that were once swirling around the newly forming Sun. By analysing the primitive meteorites that sample such asteroids, we plan to study the ancient grains they contain in order to find out more about the solar system environment prior to planet formation.

Other asteroids have been much more active, experiencing heating, melting and even igneous and volcanic activity. Any ices present in these bodies have melted, allowing liquid water to react with the rocky materials and produce water-bearing minerals. By studying the minerals in these processed meteorites we aim to learn more about the abundance and distribution of water in the early Solar System.

As well as water, many asteroids and comets also contain organics. These two components are key ingredients to life as we know it. It has been suggested that once the Earth was formed, the water and organic material necessary for the development of life were actually delivered by impacting asteroids and comets. We will therefore also study the transfer of these materials during impacts by mimicking the process in the laboratory using various targets and bolides.

The presence and action of water is not limited to the Earth, asteroids and comets. Missions to Mars have revealed its surface to be strewn with water-bearing minerals but have yet to return samples that we can study in the laboratory. We are fortunate to have a selection of meteorites that originated on Mars in our collection, and we plan to study these to learn about the action of water and the habitability of this planet.

Planned Impact

The main people who will benefit from our work, aside from our academic colleagues, are the general public and other scientists who may require analysis at fine spatial scales.

The study of meteorites lends itself to knowledge exchange for two reasons. Firstly, they are typically small and precious samples, and so encourage the development of new techniques that allow for measurement at very high spatial resolution and/or in non-destructive ways. Secondly, meteorites appeal to the public imagination; they are pieces of rock from space, and lend themselves to literally "hands-on astronomy". Every year the group handles several dozen media enquiries (the Meteorites group is second only to Dinosaurs in the number of requests for interviews it receives).

The projects described here rely on innovative techniques that we will develop further to optimise them for extraterrestrial sample research. In particular, the development of synchrotron methods and experimental protocols for the non-destructive study of extraterrestrial materials will have implications and benefits for geoscientists, material scientists and physicists. Our group has been particularly innovative in the use of computed tomography (CT) for dense samples such as meteorites, and this work will continue to develop this aspect. Improvements in software for CT scanning that will form part of our work will have broader applications in the life and physical sciences. In collaboration with our unique X-ray diffraction laboratory, we have developed equipment and optimised methods specifically for the non-destructive analysis of meteorites. By collaboratively providing access to our expertise and specialised X-ray diffraction facilities, we aim to benefit and enhance research across the wider UK cosmochemistry community.

Working at a national museum, we have a remarkable opportunity to engage with the public. For example, we will participate in "Nature Live", a daily event in which a museum scientist describes their work to the public, "Science Uncovered", an annual event where the public can talk to scientists about their work and collections, and contribute to many annual mineral and fossil 'roadshows and festivals'.

In 2018, we will have a particularly exciting opportunity. The museum is planning a temporary gallery on Meteorites, which will give us an unprecedented opportunity to showcase our work and to enhance the cultural wealth of the country.

Publications

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Krzesinska A. M. (2016) SECONDARY MINERALS IN NAKHLA: A 3D RECONSTRUCTION OF ALTERATION SEQUENCES. in METEORITICS & PLANETARY SCIENCE

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Russell Sara S. (2017) The origin, history and role of water in the evolution of the inner Solar System in Philosophical Transactions of the Royal Society of London Series A

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Shah Jay (2017) Long-lived magnetism on chondrite parent bodies in Earth and Planetary Science Letters

 
Description We have discovered that micron sized Al rich particles are abundant in primitive chondrite matrix. This means the first stage of our project has been successful. We have analysed these using the NanoSIMS for their Mg isotope composition. We have continued our work on CM and CI meteorites in support of the OSIRIS-REx mission, and found that CM1 meteorites may be a good analogue for the target asteroid of this mission.
Exploitation Route We have shown that the matrix of primitive chondrites contains small grains rich in Al. This is the first stage of our project, which is less than a year along. We will now make isotope measurements of these grains that will allow us to determine the amount of radioactive 26Al they contained. This will provide constraints on nucleosynthesis theory, thermal evolution of young planets and asteroids and on our understanding of early solar system chronology.
Sectors Education,Culture, Heritage, Museums and Collections

 
Description Collaboration with the university of Koln 
Organisation University of Cologne
Country Germany 
Sector Academic/University 
PI Contribution This is a new collaboration that has been set us as an outcome from the grant. The PDRA Dr Hezel funded by the grant moved to Germany and we continue to colloborate on planetary science projects.
Collaborator Contribution Our partner Dr Hezel has been modelling data that we acquire in our experiments.
Impact We have just had a paper accepted in the journal Meteoritics and Planetary sciences.
Start Year 2012
 
Description NanoSIMS collaboration 
Organisation Open University
Country United Kingdom 
Sector Academic/University 
PI Contribution We provided characterised samples for analysis
Collaborator Contribution The partners provided analysis for Mg and O isotopes by NanoSIMS
Impact None yet
Start Year 2017
 
Description Meteorite Blog 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact we have set up a meteorite blog, at http://blog.nhm.ac.uk/tag/meteorites-blog/
Year(s) Of Engagement Activity 2015,2016
URL http://blog.nhm.ac.uk/tag/meteorites-blog/
 
Description Meteorite twitter account 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact we have created a twitter account to communicate our work and other activities of interest related to meteorites.
Year(s) Of Engagement Activity 2015,2016
URL https://twitter.com/NHM_Meteorites
 
Description New Scientist Live lecture and exhibit 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact We participated in "New Scientist Live" event at the EXCEL centre in London, 28th September to 1st October 2016. We presented our work in the form of a talk (presented by S Russell) and with a stall demonstrating our STFC research.
Year(s) Of Engagement Activity 2016
URL https://live.newscientist.com/
 
Description School Visits 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Visits to the following school to deliver workshop:
William Perkin C of E High School, London, Sep 2016 to June 2017.
Avondale Park Primary School, London, September 2016.
Our Lady of Victories Catholic Primary School, London, September 2016.
Year(s) Of Engagement Activity 2016
 
Description Science Uncovered 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact We presented the results of our STFC work at the Science Uncovered event at the Natural History Museum, September 2015. This was an evening of science activity and included talks, exhibits and posters aimed at the public and at policy makers.
Year(s) Of Engagement Activity 2015
URL http://www.naturalhistorymuseum.org.uk/press-office/press-releases/ScienceUncovered2015.html