Mass transfer in our planetary system
Lead Research Organisation:
University College London
Department Name: Mullard Space Science Laboratory
Abstract
How and why are the atmospheres of Mars, comets, and other solar system bodies being eroded away? Our whole solar system is bathed in a flow of material from the Sun, travelling outwards at hundreds of kilometres per second. The Earth and its atmosphere are protected from this solar wind as our planet has a magnetic field that holds off the flow. Many other bodies, such as the planets Venus, Mars, and comets, are exposed directly to the wind. My research would examine how these bodies are affected by this relentless flow of solar particles. The simplest interaction is at comets. When a comet's icy nucleus nears the Sun, gas is released, forming a very thin, but very wide atmosphere. This gas gets electrically charged by several processes, forming ions. As soon as these ions are formed, they join the solar wind, and are carried away by it, creating the comet's ion tail, like paint poured into a stream of water. This process, called ion pickup, occurs where ions join an existing flow, in this case, the solar wind. Sunlight causes comet ions to glow, making the tail visible. As well as removing gas from a comet's atmosphere, the pickup process affects the solar wind, mainly by slowing it down and sometimes stopping it completely. My work has shown that tiny comets influence the solar wind over amazingly long distances - several times the distance between the Sun and Earth. The solar wind hitting the atmospheres of Venus and Mars drags ions away, forming wispy ion tails, and causing the atmospheres to lose gas. Earth-sized Venus has kept a very thick atmosphere, but smaller Mars loses its atmosphere quite easily. Today, Mars's air is too thin for liquid water to survive on the planet's surface. Long ago, before much of the gas had been lost, large lakes and rivers did exist there. So, this erosion is very important for learning how Mars's surface has changed. Exclusive measurements of this erosion are now being made by the Mars Express spacecraft. The thick atmosphere of Saturn's largest moon, Titan, also undergoes this erosion, and is now being studied by the exciting Cassini mission. Saturn's smaller moons and rings also release material around Saturn. Exactly how this happens, and what effects it has, is still a mystery. Ion pickup is very important elsewhere. Interplanetary dust doesn't produce much gas, but where there is a lot of it, such as along comet orbits, it can have big effects on the solar wind that aren't well-understood. The gas that flows into our solar system from outside is also affected: it is turned into ions and carried away again by the solar wind. Although the pickup process that occurs at these various places in the solar system are similar, there are also many differences. The main aim of my project is to help complete the picture of how the ion pickup process at a body is affected by solar wind conditions, how quickly ions are made, how big the body is, and the make-up of its atmosphere. To do this, I will use spacecraft instruments that sense individual ions, measuring their speeds, directions, and types, and use ion observations from telescopes in space and on the ground. This is a perfect time to carry out the project, with data arriving daily from Mars Express and Cassini, and soon also from Venus Express. The data will provide details of ion pickup at Mars, Venus, and at Saturn's moons and rings. Measurements already made at comets would be compared to observations from far away, and I would produce computer models to help understand the data. My work will offer better predictions of ion pickup's effects elsewhere, helping prepare for the Rosetta mission to a comet, which will observe how the pickup process changes as a comet nears the Sun, and the New Horizons mission to Pluto. Using unique data from new missions, this well-timed project will help us understand the extremely important process of ion pickup, and how it affects planets and comets nearby and at other stars.
Publications
Meier P
(2014)
A model of the spatial and size distribution of Enceladus? dust plume
in Planetary and Space Science
Jackman C
(2008)
A multi-instrument view of tail reconnection at Saturn
in Journal of Geophysical Research: Space Physics
Kanani S
(2010)
A new form of Saturn's magnetopause using a dynamic pressure balance model, based on in situ, multi-instrument Cassini measurements
in Journal of Geophysical Research: Space Physics
Coates AJ
(2015)
A new upper limit to the field-aligned potential near Titan.
in Geophysical research letters
Rouillard A
(2009)
A solar storm observed from the Sun to Venus using the STEREO, Venus Express, and MESSENGER spacecraft
in Journal of Geophysical Research: Space Physics
Regoli L
(2016)
Access of energetic particles to Titan?s exobase: A study of Cassini?s T9 flyby
in Planetary and Space Science
Walsh A
(2013)
An indication of the existence of a solar wind strahl at 10 AU
in Geophysical Research Letters
Snowden D
(2013)
Auroral electron precipitation and flux tube erosion in Titan's upper atmosphere
in Icarus
Gurnett D
(2011)
Auroral hiss, electron beams and standing Alfvén wave currents near Saturn's moon Enceladus AURORAL-LIKE PROCESSES NEAR ENCELADUS
in Geophysical Research Letters
Sembay S
(2012)
AXIOM: Advanced X-ray imaging of the magnetosheath
in Astronomische Nachrichten
Branduardi-Raymont G
(2011)
AXIOM: advanced X-ray imaging of the magnetosphere
in Experimental Astronomy
Wellbrock A
(2013)
Cassini CAPS-ELS observations of negative ions in Titan's ionosphere: Trends of density with altitude
in Geophysical Research Letters
Tokar R
(2009)
Cassini detection of Enceladus' cold water-group plume ionosphere
in Geophysical Research Letters
Teolis BD
(2010)
Cassini finds an oxygen-carbon dioxide atmosphere at Saturn's icy moon Rhea.
in Science (New York, N.Y.)
Coates A
(2012)
Cassini in Titan's tail: CAPS observations of plasma escape
in Journal of Geophysical Research: Space Physics
Wellbrock A
(2012)
Cassini observations of ionospheric photoelectrons at large distances from Titan: Implications for Titan's exospheric environment and magnetic tail
in Journal of Geophysical Research: Space Physics
Arridge C
(2016)
Cassini observations of Saturn's southern polar cusp
in Journal of Geophysical Research: Space Physics
Hill T
(2012)
Charged nanograins in the Enceladus plume
in Journal of Geophysical Research: Space Physics
Dartnell L
(2015)
Constraints on a potential aerial biosphere on Venus: I. Cosmic rays
in Icarus
Jasinski JM
(2014)
Cusp observation at Saturn's high-latitude magnetosphere by the Cassini spacecraft.
in Geophysical research letters
Nordheim TA
(2014)
Detection of a strongly negative surface potential at Saturn's moon Hyperion.
in Geophysical research letters
Tokar R
(2012)
Detection of exospheric O 2 + at Saturn's moon Dione
in Geophysical Research Letters
Roussos E
(2008)
Discovery of a transient radiation belt at Saturn
in Geophysical Research Letters
Raouafi N
(2015)
Dynamics of HVECs emitted from comet C/2011 L4 as observed by STEREO
in Journal of Geophysical Research: Space Physics
Roussos E
(2007)
Electron microdiffusion in the Saturnian radiation belts: Cassini MIMI/LEMMS observations of energetic electron absorption by the icy moons
in Journal of Geophysical Research: Space Physics
Pickett J
(2015)
Electrostatic solitary waves observed at Saturn by Cassini inside 10 R s and near Enceladus
in Journal of Geophysical Research: Space Physics
Paranicas C
(2012)
Energetic charged particle weathering of Saturn's inner satellites
in Planetary and Space Science
Roussos E
(2012)
Energetic electron observations of Rhea's magnetospheric interaction
in Icarus
Roussos E
(2008)
Energetic electron signatures of Saturn's smaller moons: Evidence of an arc of material at Methone
in Icarus
Krupp N
(2009)
Energetic particles in Saturn's magnetosphere during the Cassini nominal mission (July 2004-July 2008)
in Planetary and Space Science
Jones G
(2009)
Fine jet structure of electrically charged grains in Enceladus' plume
in Geophysical Research Letters
Jasinski J
(2016)
Flux transfer event observation at Saturn's dayside magnetopause by the Cassini spacecraft
in Geophysical Research Letters
Coates A
(2009)
Heavy negative ions in Titan's ionosphere: Altitude and latitude dependence
in Planetary and Space Science
SantolÃk O
(2011)
Intense plasma wave emissions associated with Saturn's moon Rhea PLASMA WAVES IN THE VICINITY OF RHEA
in Geophysical Research Letters
Nordheim T
(2015)
Ionization of the venusian atmosphere from solar and galactic cosmic rays
in Icarus
Tsang S
(2015)
Ionospheric photoelectrons at Venus: Case studies and first observation in the tail
in Planetary and Space Science
Marty B
(2008)
Kronos: exploring the depths of Saturn with probes and remote sensing through an international mission
in Experimental Astronomy
Roussos E
(2011)
Long- and short-term variability of Saturn's ionic radiation belts MEV ION VARIABILITY AT SATURN
in Journal of Geophysical Research: Space Physics
Steele I
(2016)
LOTUS: a low-cost, ultraviolet spectrograph
in Monthly Notices of the Royal Astronomical Society
Arridge C
(2012)
Mapping Magnetospheric Equatorial Regions at Saturn from Cassini Prime Mission Observations
in Space Science Reviews
Ozak N
(2012)
Modeling of electron fluxes in the Enceladus plume
in Journal of Geophysical Research: Space Physics
Meier P
(2015)
Modeling the total dust production of Enceladus from stochastic charge equilibrium and simulations
in Planetary and Space Science
Coates AJ
(2010)
Negative ions at Titan and Enceladus: recent results.
in Faraday discussions
Coates A
(2010)
Negative ions in the Enceladus plume
in Icarus
Masters A
(2014)
Neptune and Triton: Essential pieces of the Solar System puzzle
in Planetary and Space Science
Gowen R
(2011)
Penetrators for in situ subsurface investigations of Europa
in Advances in Space Research
Coates A
(2013)
Photoelectrons in the Enceladus plume
in Journal of Geophysical Research: Space Physics
Coates A
(2009)
Plasma environment of Jupiter family comets
in Planetary and Space Science
Stinson A
(2016)
Polarimetry of comets 67P/Churyumov-Gerasimenko, 74P/Smirnova-Chernykh, and 152P/Helin-Lawrence
in Astronomy & Astrophysics
Description | Several aspects of the transfer of mass in our solar system were investigated as part of the fellowship. These included comets, and the activity of moons orbiting the outer planets. Several spacecraft datasets were used in the study, and included some ground-breaking work on nanograins in the plume of Saturn's moon Enceladus. |
Exploitation Route | This knowledge provides a basis for further research in this field. This includes the JUICE mission to Jupiter and its moons. |
Sectors | Other |
Description | The fellow took part in numerous public engagement activities, disseminating the results and excitement of the research field to a wide audience. |
Sector | Education,Other |
Impact Types | Societal |
Description | "A Comet Revealed" Exhibit at the Royal Society Summer Science Exhibition 2016 |
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 | Leadership of "A Comet Revealed" Exhibit at the Royal Society Summer Science Exhibition, July 2016 |
Year(s) Of Engagement Activity | 2016 |
URL | https://royalsociety.org/science-events-and-lectures/summer-science-exhibition/ |
Description | "All you need to know about the Pluto mission" - article in The Register |
Form Of Engagement Activity | A magazine, newsletter or online publication |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Article on the New Horizons probe and how planetary space missions are run. |
Year(s) Of Engagement Activity | 2015 |
Description | "Dibendraw" - 30 minute Welsh-language documentary on Rosetta. |
Form Of Engagement Activity | A broadcast e.g. TV/radio/film/podcast (other than news/press) |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Public/other audiences |
Results and Impact | 30 minutes programme on career in space science and activities related to the Rosetta mission. Several requests for further information received afterwards. |
Year(s) Of Engagement Activity | 2015 |
Description | BBC News (several bulletins) - Interview on Rosetta mission to Comet 67P |
Form Of Engagement Activity | A broadcast e.g. TV/radio/film/podcast (other than news/press) |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Interview on the scientific background to the Rosetta mission to Comet 67P. Requests for more information received. |
Year(s) Of Engagement Activity | 2014 |
Description | BBC Radio 4 Sound Places project |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Public/other audiences |
Results and Impact | Interview on the crossing of Comet Hyakutake's tail, and the sonification of the relevant data. |
Year(s) Of Engagement Activity | 2017 |
Description | BBC Radio Cymru - Welsh-language interview on space travel |
Form Of Engagement Activity | A broadcast e.g. TV/radio/film/podcast (other than news/press) |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | BBC Radio Cymru - Welsh-language interview on the Challenger Accident. |
Year(s) Of Engagement Activity | 2016 |
Description | BBC Sky at Night - Interview on Neptune's moon Triton |
Form Of Engagement Activity | A broadcast e.g. TV/radio/film/podcast (other than news/press) |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Public/other audiences |
Results and Impact | Interviewed on the nature of Neptune's moon Triton, October 2014. Queries about the topic received afterwards. |
Year(s) Of Engagement Activity | 2014 |
Description | BBC Sky at Night - Interview on Rosetta Mission and cometary science, 2 October 2016 |
Form Of Engagement Activity | A broadcast e.g. TV/radio/film/podcast (other than news/press) |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Public/other audiences |
Results and Impact | Interview on Rosetta Mission and cometary science on BBC Sky at Night. |
Year(s) Of Engagement Activity | 2016 |
Description | BBC Sky at Night - Interview on Saturn's moon Enceladus |
Form Of Engagement Activity | A broadcast e.g. TV/radio/film/podcast (other than news/press) |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Public/other audiences |
Results and Impact | BBC Sky at Night - Interview on Saturn's moon Enceladus. Several queries from members of the public were received. |
Year(s) Of Engagement Activity | 2015 |
Description | BBC World News - Interview on Pluto and New Horizons mission |
Form Of Engagement Activity | A broadcast e.g. TV/radio/film/podcast (other than news/press) |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Interview on Pluto and New Horizons mission on BBC World News. Queries received afterwards from more information. |
Year(s) Of Engagement Activity | 2015 |
Description | BBC World Service "Science in Action" |
Form Of Engagement Activity | A broadcast e.g. TV/radio/film/podcast (other than news/press) |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Radio interview on space missions to comets. Queries received about topics covered in the interview. |
Year(s) Of Engagement Activity | 2014 |
Description | Bright Club - scientific stand-up comedy (Geraint Jones) |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | Scientific stand-up session at the Bloomsbury Theatre. |
Year(s) Of Engagement Activity | 2016 |
Description | Cassini Caught in Hyperion's Electron Beam - quoted in ESA press release |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Media (as a channel to the public) |
Results and Impact | European Space Agency press release on paper led by MSSL planetary group member Tom Nordheim. Nordheim and Geraint Jones quoted in the press release. Release led to numerous online and print articles. |
Year(s) Of Engagement Activity | 2014 |
Description | Ice Worlds exhibit at the Royal Society |
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 | Leadership of the Ice Worlds exhibit at the Royal Society Summer Science Exhibition 2013. Approximately 12,000 visitors during the week of the exhibition. |
Year(s) Of Engagement Activity | 2013 |
URL | http://sse.royalsociety.org/2013/exhibits/ice-worlds/ |
Description | Interview on the Rosetta mission; ORF Radio, Austria |
Form Of Engagement Activity | A broadcast e.g. TV/radio/film/podcast (other than news/press) |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Interview on the Rosetta mission. |
Year(s) Of Engagement Activity | 2016 |
Description | Keynote Scientific Talk 2015 at the National Eisteddfod of Wales |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Public/other audiences |
Results and Impact | Keynote Scientific Talk 2015 in the science pavilion of the national Eisteddfod, Meifod, on the topic of cometary science. |
Year(s) Of Engagement Activity | 2015 |
Description | Live coverage of Rosetta mission end, Nature News & Comment, 30 September 2016 |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Media (as a channel to the public) |
Results and Impact | Live video coverage of Rosetta mission end, on Nature News & Comment website. |
Year(s) Of Engagement Activity | 2016 |
URL | http://www.nature.com/news/rosetta-crashes-into-comet-live-from-the-nature-studio-1.20684 |
Description | NASA Press Conference Panel Member "The Battle of Fire and Ice: New Scientific Results from Comet ISON" |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Media (as a channel to the public) |
Results and Impact | Press conference held at Fall AGU Meeting, San Francisco on the topic of Comet ISON. Numerous requests for more information received from members of the media. |
Year(s) Of Engagement Activity | 2013 |
Description | Nature News story "Mission accomplished: Rosetta crashes into comet" |
Form Of Engagement Activity | A press release, press conference or response to a media enquiry/interview |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Media (as a channel to the public) |
Results and Impact | Quoted in Nature news story on topic of cometary science, 2 October 2016. |
Year(s) Of Engagement Activity | 2016 |
URL | http://www.nature.com/news/mission-accomplished-rosetta-crashes-into-comet-1.20705?WT.ec_id=NATURE-2... |
Description | Newyddion - Welsh language interview on MSSL and its science programme on main Welsh TV news programme |
Form Of Engagement Activity | A broadcast e.g. TV/radio/film/podcast (other than news/press) |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Public/other audiences |
Results and Impact | Interview led to queries about space exploration, planetary science from members of the public who had seen the interview. |
Year(s) Of Engagement Activity | 2014 |
Description | Presentation on "The JUICE mission to Jupiter" (West of London Astronomical Society) |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | Talk given on the JUICE mission; a good audience response, with plenty of questions. |
Year(s) Of Engagement Activity | 2016 |
Description | Presentation on advances in space exploration, London |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | Talk on space exploration for readers of The Register. Many questions from attendees. |
Year(s) Of Engagement Activity | 2014 |
Description | Public Talk on The ESA JUICE mission to the icy moons of Jupiter (British Astronomical Association National Meeting, Chelmsford) |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Public/other audiences |
Results and Impact | An invited talk given as part of the British Astronomical Association's meeting on "Robotic exploration of the Solar System". |
Year(s) Of Engagement Activity | 2016 |
URL | https://www.britastro.org/meetings |
Description | Public Talk on The Icy Moons of Jupiter and Saturn (National Maritime Museum, Greenwich) |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Public/other audiences |
Results and Impact | A talk given at the Flamsteed Astronomy Society, Greenwich. Between 50 and 80 attendees; many questions asked afterwards. |
Year(s) Of Engagement Activity | 2017 |
URL | http://flamsteed.info/ |
Description | Q&A with American International School Dhaka, Bangladesh |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Schools |
Results and Impact | Question and answer session with 10-11 year olds at the American International School Dhaka on many space and astronomy-related topics. Conducted over Skype. |
Year(s) Of Engagement Activity | 2017 |
Description | Rosetta exhibit at the National Eisteddfod of Wales, around 40,000 visitor to the science pavilion. |
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 | Rosetta exhibit at the National Eisteddfod of Wales, around 40,000 visitor to the science pavilion during one week in August 2015. Numerous questions from members of the public. |
Year(s) Of Engagement Activity | 2015 |
Description | Space Boffins podcast |
Form Of Engagement Activity | A broadcast e.g. TV/radio/film/podcast (other than news/press) |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Interview on planetary exploration and plans for future comet missions. |
Year(s) Of Engagement Activity | 2014 |
Description | Talk to Whiston Society, Clare College, Cambridge University, on The Cassini Mission |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Regional |
Primary Audience | Undergraduate students |
Results and Impact | One hour talk given to around 50 science students students. Many questions answered afterwards. |
Year(s) Of Engagement Activity | 2018 |
Description | Y Cosmos - several appearances on Welsh-language documentary series on astronomy. |
Form Of Engagement Activity | A broadcast e.g. TV/radio/film/podcast (other than news/press) |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Public/other audiences |
Results and Impact | Interviewed on several topics related to planetary science, and interviews used throughout the series of programmes. |
Year(s) Of Engagement Activity | 2014 |