S.J. de Vet
Please Note
18 records found
1
Experimental debris flows and rock avalanches under different gravities
To the Moon and Mars in an airplane
In this study, we experimentally explored the effects of gravity on the dynamics of dry mass movements and those lubricated by a liquid. We performed rotating drum experiments under varying gravity (from ~0.1g to 2g, with g=9.81ms-2). The lower and hyper-gravity conditions were created by flying, respectively, parabolic trajectories and steep turns with a Cessna Citation II aircraft (PH-LAB), in which the rotating drum set-up was installed. In the rotating drum (diameter=50 cm), we tested how dry and wet granular flows responded to different gravity by measuring flow depth, density, compaction and dilation, and internal grain dynamics. Reference experiments with varying drum-rotation speeds were performed under Earth gravity to determine the relative effects of centrifugal force versus gravity, and aircraft vibrations.
Preliminary analyses show that gravity changes the dynamics of both dry and wet granular flows in our drum, and that these effects are more pronounced for wet granular flows. Under higher gravities (>1g), the granular flows become more compacted, which pushes the water out of the mixture and decreases the water content of the granular flow itself. As a result, the interparticle friction increases and the centre of mass shifts upslope in the drum. At lower gravities (<0.7g), the granular flows dilate, increasing the pore space in the sediment-water mixture, resulting in an increase in air in the inter-particle pore space. This increases the relative importance of flow resisting forces relative to lubricating forces within the mixture, shifting the center of mass of the mixture upslope. The results under varying gravities seem to imply that, for a given ratio of sediment to water, an optimum gravity exist for peak water-lubricated granular flow mobility.
Comparison of the results under varying gravity with those of the reference experiments with varying drum rotation speeds under 1g confirm that gravity has a unique effect on the flow dynamics of granular flows. In particular, on the dilation of the flowing mixture and the interparticle behaviour. However, as changing drum-rotation speed also shifts the centre of mass of the flowing mixture, further analysis will focus on the combined effects of dilation, shifting centre of mass, and the steepening slope in the drum for all experiments. ...
In this study, we experimentally explored the effects of gravity on the dynamics of dry mass movements and those lubricated by a liquid. We performed rotating drum experiments under varying gravity (from ~0.1g to 2g, with g=9.81ms-2). The lower and hyper-gravity conditions were created by flying, respectively, parabolic trajectories and steep turns with a Cessna Citation II aircraft (PH-LAB), in which the rotating drum set-up was installed. In the rotating drum (diameter=50 cm), we tested how dry and wet granular flows responded to different gravity by measuring flow depth, density, compaction and dilation, and internal grain dynamics. Reference experiments with varying drum-rotation speeds were performed under Earth gravity to determine the relative effects of centrifugal force versus gravity, and aircraft vibrations.
Preliminary analyses show that gravity changes the dynamics of both dry and wet granular flows in our drum, and that these effects are more pronounced for wet granular flows. Under higher gravities (>1g), the granular flows become more compacted, which pushes the water out of the mixture and decreases the water content of the granular flow itself. As a result, the interparticle friction increases and the centre of mass shifts upslope in the drum. At lower gravities (<0.7g), the granular flows dilate, increasing the pore space in the sediment-water mixture, resulting in an increase in air in the inter-particle pore space. This increases the relative importance of flow resisting forces relative to lubricating forces within the mixture, shifting the center of mass of the mixture upslope. The results under varying gravities seem to imply that, for a given ratio of sediment to water, an optimum gravity exist for peak water-lubricated granular flow mobility.
Comparison of the results under varying gravity with those of the reference experiments with varying drum rotation speeds under 1g confirm that gravity has a unique effect on the flow dynamics of granular flows. In particular, on the dilation of the flowing mixture and the interparticle behaviour. However, as changing drum-rotation speed also shifts the centre of mass of the flowing mixture, further analysis will focus on the combined effects of dilation, shifting centre of mass, and the steepening slope in the drum for all experiments.
The Isidis Planitia impact basin on Mars is located on the north-south dichotomy boundary, bordered by Utopia Planitia and the Syrtis Major volcanic province. The basin records a long geological history of global and regional events of impact-induced, volcanic and sedimentary processes. This is evident in the presence of a high-density subsurface mass concentration, the strongest on Mars outside the major volcanic provinces. The nature of this interior structure remains poorly understood despite modelling efforts (e.g., [1-3]). Isidis Planitia’s surface also hosts the densest clustering of pitted cones [4,5]. The formation mechanism of these landforms, characterised by a conical mound with a central depression, remains debated as volcanic [6], sedimentary [4] or glacial [7].
We present an integrated approach to Isidis Planitia, showing that pitted cones are topographically constrained by surface wrinkle ridges driven by its subsurface structure. The subsurface is modelled using impact scaling laws combined with geological context to formulate a multi-layered model, which is fit to the local gravity field. Resultant structural elements are consistent with impact theory [8-10], estimated structures below Lunar basins [11,12], as well as mapped basins [13]. However, the gravity field cannot be constrained using infill, scaling laws and realistic density values. The models require mantle-like materials in the innermost parts of the basin. This element does not reconcile with expectations of impact theory nor basin infill, and is interpreted as significant post-impact plutonic intrusions.
This intrusive element is linked to a set of wrinkle ridge surface expressions with anomalous direction and dip. Two distinct formations of ridges are identified: an initial radial set of ridges and a latter concentric inward-dipping formation. This anomalous concentric set is not mirrored in Lunar basins [14,15] nor in Martian basins Utopia and Hellas [16,17]. The initial set is likely driven by regional compressive effects. The latter formation is driven by a stress field in the inner basin, which could be achieved during pluton inflation.
The pitted cones are shown to correlate with the basin topography dominated by the wrinkle ridges. The population conforms to both sets of pre-existing wrinkle ridges in distinct surface flow patterns. They are most consistent with volcanic rootless cones formed by lavas interacting with near-surface volatiles. The lava could be sourced from the intrusive magmatism, addressing the lack of other sources [6]. Overall, this study links Isidis Planitia’s subsurface structure to surface morphology. It could redefine the complex and dynamic basin, offering new insights into the active geological evolution of Mars.
To strengthen this effort, a new Planetary Science Network in the Netherlands is being established. The network builds on the existing expertise in solar system research within the Dutch scientific community and aims to develop a framework for identifying key observables that enable the detection and assessment of planetary habitability through both in situ and remote sensing observations.
The research is organised around three main themes. The first theme focuses on planetary interiors, using Ganymede as a case study. The second theme examines surface morphology, particularly landform development, with Mars serving as the primary case study. The third theme investigates surface composition by comparing Earth's oldest geological surfaces with those of Mars and icy moons.
Through a synergistic approach within the network, these themes will produce both case-study-specific observables and more general observables that can be applied across the solar system and to the growing number of known exoplanetary systems. The network aims to strengthen the position of the Dutch planetary science community and support active contributions to the development of instruments for future planetary exploration missions. In addition, it will foster closer collaboration with the strong Dutch exoplanet research community, helping to bridge the gap between what should ideally be observed and what is currently feasible to observe.
This presentation introduces the network, its research goals, and its strategy for advancing the study of planetary habitability, while inviting collaboration and discussion within the international planetary science community. ...
To strengthen this effort, a new Planetary Science Network in the Netherlands is being established. The network builds on the existing expertise in solar system research within the Dutch scientific community and aims to develop a framework for identifying key observables that enable the detection and assessment of planetary habitability through both in situ and remote sensing observations.
The research is organised around three main themes. The first theme focuses on planetary interiors, using Ganymede as a case study. The second theme examines surface morphology, particularly landform development, with Mars serving as the primary case study. The third theme investigates surface composition by comparing Earth's oldest geological surfaces with those of Mars and icy moons.
Through a synergistic approach within the network, these themes will produce both case-study-specific observables and more general observables that can be applied across the solar system and to the growing number of known exoplanetary systems. The network aims to strengthen the position of the Dutch planetary science community and support active contributions to the development of instruments for future planetary exploration missions. In addition, it will foster closer collaboration with the strong Dutch exoplanet research community, helping to bridge the gap between what should ideally be observed and what is currently feasible to observe.
This presentation introduces the network, its research goals, and its strategy for advancing the study of planetary habitability, while inviting collaboration and discussion within the international planetary science community.
Approach: The development of both online labs is largely driven by student participation. First, 2D images are taken of the meteorites, and displayed on the UML website, accompanied by a brief description, including name, location of fall or find, year of collection, and classification. Then, 3D representations of the meteorites are made via Structure from Motion (SfM) photogrammetry using the software Agisoft Metashape Professional and stored on SketchFab, with links to the DML and UML websites. Of selected specimens thin sections are made and full thin section microscope photographs and sections in PPL and XPL will be added to the online collection (AXIOM).
Use in education: DML and UML are already actively used in education. The descriptions of the meteorites for the UML are written by the students as part of the Planetology, an Introduction course taught at the department of Earth Sciences at Utrecht University. 3D models from the DML are used to familiarise students with properties of meteorites that can be related to specific processes, such as fusion crusts from ablation during atmospheric entry, compositional differences between differentiated and undifferentiated meteorites [1,2]. Also, the DML 3D models are used for a meteorite or meteorwrong practicum during the courses Planetary Science at BSc and MSc level.
Outreach: Over the past years, the 3D models have been used in several outreach activities. In an online lecture for the popular ‘Universiteit van Nederland’, we discussed several Dutch meteorites using 3D models in a chroma key (‘green screen’) environment to explain properties of meteorites, their taxonomy and implications for planet formation. Based on the renderings, 3D prints have been made of the Dutch Utrecht (’Loevenhoutje’ fragment) and Broek in Waterland meteorites for outreach activities at the Space Expo Museum. To mark the 150-year anniversary of the Diepenveen meteorite fall on 27 October 2023, 6:1 scaled model was created for a monument based on the 3D model of Diepenveen and revealed on the day of the impact anniversary in the town’s centre.
Outlook: Building upon our current experiences with the Delft Meteorite Lab focussing on photogrammetry workflow development and educational applications, and the Utrecht Meteorite Lab, linking to data from various material characterisation methods, we aim to create the ‘Dutch Meteorite Lab’as a national hub to explore meteorites in study collections found across the Netherlands.
References: [1] de Vet S. J. (2024) Proceedings of the IMC, Redu, 59-62 [2] Guedes D., Zucolotto M., Silva L., Brenha S., and Canelle J. B. (2010). Meteoritics and Planetary Science Supplement, MetSoc 73. ...
Approach: The development of both online labs is largely driven by student participation. First, 2D images are taken of the meteorites, and displayed on the UML website, accompanied by a brief description, including name, location of fall or find, year of collection, and classification. Then, 3D representations of the meteorites are made via Structure from Motion (SfM) photogrammetry using the software Agisoft Metashape Professional and stored on SketchFab, with links to the DML and UML websites. Of selected specimens thin sections are made and full thin section microscope photographs and sections in PPL and XPL will be added to the online collection (AXIOM).
Use in education: DML and UML are already actively used in education. The descriptions of the meteorites for the UML are written by the students as part of the Planetology, an Introduction course taught at the department of Earth Sciences at Utrecht University. 3D models from the DML are used to familiarise students with properties of meteorites that can be related to specific processes, such as fusion crusts from ablation during atmospheric entry, compositional differences between differentiated and undifferentiated meteorites [1,2]. Also, the DML 3D models are used for a meteorite or meteorwrong practicum during the courses Planetary Science at BSc and MSc level.
Outreach: Over the past years, the 3D models have been used in several outreach activities. In an online lecture for the popular ‘Universiteit van Nederland’, we discussed several Dutch meteorites using 3D models in a chroma key (‘green screen’) environment to explain properties of meteorites, their taxonomy and implications for planet formation. Based on the renderings, 3D prints have been made of the Dutch Utrecht (’Loevenhoutje’ fragment) and Broek in Waterland meteorites for outreach activities at the Space Expo Museum. To mark the 150-year anniversary of the Diepenveen meteorite fall on 27 October 2023, 6:1 scaled model was created for a monument based on the 3D model of Diepenveen and revealed on the day of the impact anniversary in the town’s centre.
Outlook: Building upon our current experiences with the Delft Meteorite Lab focussing on photogrammetry workflow development and educational applications, and the Utrecht Meteorite Lab, linking to data from various material characterisation methods, we aim to create the ‘Dutch Meteorite Lab’as a national hub to explore meteorites in study collections found across the Netherlands.
References: [1] de Vet S. J. (2024) Proceedings of the IMC, Redu, 59-62 [2] Guedes D., Zucolotto M., Silva L., Brenha S., and Canelle J. B. (2010). Meteoritics and Planetary Science Supplement, MetSoc 73.
The FRIPON fireball project was initially conceived and founded in France in 2014 with a grant from the ANR (Agence Nationale de la Recherche), the objective was to cover the country with a dense network of all-sky cameras (~ a hundred with 80 km spacing). We built (Colas at al 2020) [1] a centralized network, a data storage architecture and a real-time data processing (astrometry of each camera, triangulation of each event to calculate the trajectory of the bright flight and finally determination of the scientific parameters: orbit, incoming mass, final mass, etc.). A catalog of orbits is produced each year and is available on the fireball.fripon.org website. The FRIPON project is designed as a real-time network, the aim of which is to trigger a search in the field within 24 hours of the fall in order to recover fresh meteorites.
Extension and results
The architecture developed for the network allows for easy expansion, and from 2016, scientists from neighboring countries were interested in joining the project using the same hardware, software and infrastructure. The main extensions involved Italy (PRISMA), Germany (FRIPON-Germany), Romania (MOROI), the United Kingdom (SCAMP), Canada (DOME), the Netherlands (DOERAK), Spain (SPMN), Belgium (FRIPON-Belgium), Switzerland (FRIPON-Switzerland), South America (FRIPON-Andino), Morocco (MOFID) and Senegal (ASAMAAN). FRIPON (www.fripon.org) is now an international project and the French network is now FRIPON-VigieCiel (www.vigie-ciel.org) a merger of the camera network and of the Vigie-Ciel citizen science project supported by Muséum national d'Histoire naturelle with the aim of involving the general public in finding meteorites by learning how to identify them and thus take part in research. Ten years after the start of the network, we now have 250 active cameras, we have obtained more than 10,000 orbits and our data has been used in the recovery of 7 meteorites (Cavezzo 2020, Winchcombe 2020, Kindberg 2021, Saint-Pierre-le-Viger 2023, Matera 2023, Menetréol 2023, Ribbeck 2024). It is important to note that over these 10 years, more than 20 searches have been organized without positive results, as the recovery efficiency is often far from 100% due to vegetation, private land, etc.
Recovery statistics
Roughly 600 detections per year included at least one French camera, as described in (Colas et al 2020) [1] this corresponds to objects larger than 1 cm and is compatible with the surface area of the national territory (10⁶ km²) according to the previous estimate (Brown et al 2002) [2]. As it also predicts the fall of around 10 meteorites per year for France, we hoped at the start of the project to recover about one meteorite per year, which seems realistic: 50% of meteorites fall during the day, cloud cover is around 50% and ground searches are difficult one time out of two. Another clue is that in the 19th century, one meteorite was recovered every two years in France (Colas, 2020) [1]. Unfortunately, after 10 years of operation, we have only recovered 2 meteorites in France, which is a little disappointing but still better than the 20th century efficiency of one meteorite every 10 years. In the end, the realistic recovery rate seems close to one meteorite per year, but for all of Europe! Since the start of the program in 2015, we found 40 events with a final mass greater than 100g and 10 for 500g and more. These data are compatible with our initial estimate, but the recovery success is low due partly to agricultural changes from small farms where owners could easily identify "strange" stones to big intensive farms.
The case of 2023 CX1
Asteroid 2023 CX1 was discovered by Krisztián Sárneczky of the Konkoly Observatory on 12 February 2023, just 7 hours before it was due to hit the Earth, which made it possible to track it and calculate its orbit very precisely. Most of the telescopic data was obtained by amateurs. It is important to point out that we had to use data from different networks (FRIPON, GMN, AllSky 7, UKMON) and security cameras to calculate the atmospheric entry parameters. The potential strewnfield was then determined in parallel by several groups. The FRIPON/Vigie-ciel collaboration quickly mobilized its network and set up a field search. 4 stones were thus found by children, 4 others by amateurs and finally only 4 others by scientists who were not even meteorite specialists! In the end, amateurs played a fundamental role in the recovery success at all stages of the event: telescopic and fireball data as well as field searches.
Conclusion
The 7 meteorites found in Europe in the last 5 years would not have been found without the presence of fireball networks to give the alert and calculate the strewnfields. In Europe, we are fortunate to have a number of networks (FRIPON, GMN, AllSky7, DFN, etc.) that enable us to detect these events exhaustively. The success of our research is also largely due to citizen science programs such as Vigie-Ciel, which make it possible to organize effective field searches.
References: [1] Colas et al. (2020) Astronomy and Astrophysics 644, A53; [2] Brown et al (2002) Nature, Volume 420, Issue 6913 ...
The FRIPON fireball project was initially conceived and founded in France in 2014 with a grant from the ANR (Agence Nationale de la Recherche), the objective was to cover the country with a dense network of all-sky cameras (~ a hundred with 80 km spacing). We built (Colas at al 2020) [1] a centralized network, a data storage architecture and a real-time data processing (astrometry of each camera, triangulation of each event to calculate the trajectory of the bright flight and finally determination of the scientific parameters: orbit, incoming mass, final mass, etc.). A catalog of orbits is produced each year and is available on the fireball.fripon.org website. The FRIPON project is designed as a real-time network, the aim of which is to trigger a search in the field within 24 hours of the fall in order to recover fresh meteorites.
Extension and results
The architecture developed for the network allows for easy expansion, and from 2016, scientists from neighboring countries were interested in joining the project using the same hardware, software and infrastructure. The main extensions involved Italy (PRISMA), Germany (FRIPON-Germany), Romania (MOROI), the United Kingdom (SCAMP), Canada (DOME), the Netherlands (DOERAK), Spain (SPMN), Belgium (FRIPON-Belgium), Switzerland (FRIPON-Switzerland), South America (FRIPON-Andino), Morocco (MOFID) and Senegal (ASAMAAN). FRIPON (www.fripon.org) is now an international project and the French network is now FRIPON-VigieCiel (www.vigie-ciel.org) a merger of the camera network and of the Vigie-Ciel citizen science project supported by Muséum national d'Histoire naturelle with the aim of involving the general public in finding meteorites by learning how to identify them and thus take part in research. Ten years after the start of the network, we now have 250 active cameras, we have obtained more than 10,000 orbits and our data has been used in the recovery of 7 meteorites (Cavezzo 2020, Winchcombe 2020, Kindberg 2021, Saint-Pierre-le-Viger 2023, Matera 2023, Menetréol 2023, Ribbeck 2024). It is important to note that over these 10 years, more than 20 searches have been organized without positive results, as the recovery efficiency is often far from 100% due to vegetation, private land, etc.
Recovery statistics
Roughly 600 detections per year included at least one French camera, as described in (Colas et al 2020) [1] this corresponds to objects larger than 1 cm and is compatible with the surface area of the national territory (10⁶ km²) according to the previous estimate (Brown et al 2002) [2]. As it also predicts the fall of around 10 meteorites per year for France, we hoped at the start of the project to recover about one meteorite per year, which seems realistic: 50% of meteorites fall during the day, cloud cover is around 50% and ground searches are difficult one time out of two. Another clue is that in the 19th century, one meteorite was recovered every two years in France (Colas, 2020) [1]. Unfortunately, after 10 years of operation, we have only recovered 2 meteorites in France, which is a little disappointing but still better than the 20th century efficiency of one meteorite every 10 years. In the end, the realistic recovery rate seems close to one meteorite per year, but for all of Europe! Since the start of the program in 2015, we found 40 events with a final mass greater than 100g and 10 for 500g and more. These data are compatible with our initial estimate, but the recovery success is low due partly to agricultural changes from small farms where owners could easily identify "strange" stones to big intensive farms.
The case of 2023 CX1
Asteroid 2023 CX1 was discovered by Krisztián Sárneczky of the Konkoly Observatory on 12 February 2023, just 7 hours before it was due to hit the Earth, which made it possible to track it and calculate its orbit very precisely. Most of the telescopic data was obtained by amateurs. It is important to point out that we had to use data from different networks (FRIPON, GMN, AllSky 7, UKMON) and security cameras to calculate the atmospheric entry parameters. The potential strewnfield was then determined in parallel by several groups. The FRIPON/Vigie-ciel collaboration quickly mobilized its network and set up a field search. 4 stones were thus found by children, 4 others by amateurs and finally only 4 others by scientists who were not even meteorite specialists! In the end, amateurs played a fundamental role in the recovery success at all stages of the event: telescopic and fireball data as well as field searches.
Conclusion
The 7 meteorites found in Europe in the last 5 years would not have been found without the presence of fireball networks to give the alert and calculate the strewnfields. In Europe, we are fortunate to have a number of networks (FRIPON, GMN, AllSky7, DFN, etc.) that enable us to detect these events exhaustively. The success of our research is also largely due to citizen science programs such as Vigie-Ciel, which make it possible to organize effective field searches.
References: [1] Colas et al. (2020) Astronomy and Astrophysics 644, A53; [2] Brown et al (2002) Nature, Volume 420, Issue 6913
To date, in-situ Mars exploration has provided planetary scientists with a unique opportunity to understand the planet and the history of the solar system, as 45% of the Martian surface is comprised of geological units dated more than 3.7 billion years old. However, fundamental mechanisms of surface geological and geomorphological features on Mars cannot be determined by current missions, as they are limited by small surface coverage or limited resolution. As a result, there is a limited understanding of the presence of turbidite deposits along the Martian dichotomy, which would provide direct evidence of ancient deep-water environments. Additionally, the mechanisms of equatorial Recurring Slope Lineae (RSL) are debated along with glacier-like forms (GLFs) present in the polar regions of Mars. Studying them in-situ would enable further comprehension of the extent of surface liquid water, paleoclimates on Mars, and the possibility of future human habitation on Mars. The need for large-scale spatiotemporal datasets is addressed by a novel mission architecture that uses a swarm of wind-driven mobile impactors - the Tumbleweed Rovers. The Ultimate Tumbleweed Mission is able to provide high coverage and high-resolution imaging at rugged and previously inaccessible locations on Mars. The objective of this paper is to investigate the utility of a multispectral camera and a hand-lens style imager integrated into a swarm of Tumbleweed Rovers, in order to answer long-standing questions regarding the geologic history and modern geomorphology on Mars. We conduct a definitive feasibility study of the instrumentation on a swarm of Tumbleweed Rovers, defining design requirements to attain baseline science goals. The proposed multispectral camera is capable of distinguishing between the major mineral groups relevant to Mars, e.g. olivine, iron-oxides, and hydrated minerals. We also propose a hand-lens style imager, capable of determining the distribution of grain sizes present in common sedimentary formations (sandstones, siltstones, and mudstones). With this instrumentation, we show that the Ultimate Tumbleweed Mission (UTM) enables searching for turbidites, constraining the composition and mechanics of RSL, and mapping the extent of glacier-like forms in the high latitudes. In this paper, we demonstrate that Tumbleweed Rovers can significantly improve our understanding of the geology and modern geomorphology of Mars by providing high-resolution images at rugged, high-latitude locations.