“Venus: The Next Target of Planetary Exploration” with Richard Ghail (Royal Holloway, University of London, UK)

Three new missions recently selected for implementation by NASA (DaVinci and Veritas) and ESA (EnVision) are opening a new era of space exploration, this time focusing on Earth’s neighbour and sibling, Venus. Few missions have been sent to Venus since the time of the early Venera missions by the then Soviet Union. An important reason lies with the substantial challenges that exploration of Venus faces because of its extreme surface conditions (450°C, 90 atmospheres pressure, and corrosive chemistry). The longest-lived Venera lander, for instance, survived for only two hours. A second factor is that the permanent cloud cover means that the only way to image the surface at high resolution is with an expensive, power-hungry and data-intensive imaging radar system.

But Venus is of interest even beyond planetary science because of its similarity in size to the Earth and because its atmosphere may have experienced a runaway-greenhouse, perhaps as recently as a billion years ago, turning a possibly habitable planet into an almost hellish place. How is it that two planets so similar in size, composition and distance from the Sun, can be so different? The three recently selected missions seek to address different and complementary aspects of these questions: DaVinci will provide a very detailed geochemical ‘snapshot’ through the atmosphere; Veritas will make a global geophysical survey; while EnVision will undertake a set of complementary targeted observations of the atmosphere, surface and interior. Its goals are to locate and characterise geological activity on the surface and to track how that activity drives atmospheric chemistry, especially in the clouds, and to infer how both evolved through time and, in particular, what evidence there may be for past oceans. To do so, EnVision carries an imaging radar (VenSAR), a sounding radar (SRS), a spectrometer suite (VenSpec-U and -H) and mapper (VenSpec-M) and will additionally conduct radio science experiments (RSE).

Richard Ghail is a Professor in the Department of Earth Sciences of the Royal Holloway University of London. Richard specializes in intra-plate tectonics on Earth and Venus uses radar interferometry (InSAR) to measure fault movements on exceedingly small scales of millimetres per year. He applies the technology to monitoring the surface effects of engineering in the ground and to understanding impact of intra-plate deformation on civil engineering infrastructure, particularly tunnels. He founded the Engineering Scale Geology Research Group to develop these ground investigation techniques and advance their study. Richard proposed Envision and led the ESA science study up to its selection. The mission will apply many of the InSAR technologies and techniques developed for ground engineering to characterise and measure geological activity on Venus.

Webinar was recorded on September 30, 2021

Mark Sargent, ISSI Science Program Manager

The ISSI Directorate appointed Dr. Mark Sargent as ISSI’s new Science Program Manager as of September 15, 2021. Mark Sargent succeeds Maurizio Falanga, who was the ISSI Science Program Manager since 2009. As of August 1, 2021, Maurizio is now ISSI’s Administrative Director.
Mark Sargent was born in Zurich, Switzerland and graduated with a degree in Physics (with specialisation in geophysics) from the ETH Zurich. After completing his PhD studies at the ETH Zurich in Switzerland in 2007, Mark went on to postdoctoral positions at the Max-Planck-Institute for Astronomy in Heidelberg (MPIA) and at the “Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA)” near Paris. He subsequently joined the Astronomy Centre at the University of Sussex in 2013 as a member of their teaching and research faculty, and in 2016/17 also held the position of Royal Society Leverhulme Trust Senior Research fellow. Before joining ISSI, Mark spent a year at EPFL in Lausanne and Geneva Observatory as visiting fellow of the Swiss National Science Foundation.
Dr. Mark Sargent, Science Program Manager
Mark works in the field of galaxy formation and evolution, with a particular focus on how the gas and dust content of galaxies evolves over time, and how the process of star formation plays out in different types of galaxies, both in the nearby and distant Universe.
He is author or co-author of about 150 publications and in his career has mentored approximately 30 students for MSc or PhD projects. He currently chairs the Square Kilometre Array Science Working Group on Extragalactic Continuum science, and has recently also served the community as chair of the e-MERLIN time allocation committee and as a member of the UK radio astronomy strategy review panel.
Mark is very much looking forward to interacting with the whole ISSI community, and to “absorbing” as large a dose as possible of the science discussions that will take place at ISSI in the coming years.

Auroral Physics

Volume 78 in the Space Sciences Series of ISSI

This volume surveys our current scientific understanding of the terrestrial aurora. It is organized into eleven reviews detailing theoretical and observational aspects of characteristic auroral morphologies, and how these in turn are organized according to local time, latitude, and activity level. 

Popular descriptions often attribute the aurora to the interaction of charged particles from the solar wind with atoms in the upper atmosphere. In fact, most auroras are not the result of direct entry of solar wind particles. Rather, as detailed in this volume, auroral particle acceleration and generation of auroral forms occur primarily within the magnetosphere. Importantly, many key aspects of the aurora – most notably, the physical mechanisms responsible for the generation of discrete arcs – are still unexplained, and auroral physics continues to be an active area of scientific research. Each review chapter therefore includes a summary of open questions for further investigation. 

This volume results from the ISSI Workshop Auroral Physics held from 6 to 10 August 2018.

This volume is edited by D.J. Knudsen, J.E. Borovsky, T. Karlsson, R. Kataoka, N. Partamies

This volume is co-published in Space Science Reviews in the Topical Collection “Auroral Physics” (Partial Open Access) >>

Hard Cover Book >>


A Word form the ISSI Executive Director

Dear friends of ISSI!

Dear visitors of our website!

It almost feels like a relaunch! Since the beginning of this month of September, we have visitors again at ISSI. We started off with an International Team in the first week of the month (Sept 6–10) working on plasmas in the vicinity of comets and of Mars and this week (Sept 13–17) we host a team working on Pulsars. These are the first in person team meetings at ISSI in 1.5 years, since March 2020! There will be more International Teams coming to ISSI in September and the following months as you can see in our calendar which is quite full. Moreover, this second week of September (13–17) we are hosting the first ISSI Workshop since the Deep Earth Interior Workshop a year ago! The subject of the present workshop is the Evolution of the Interior of Venus. The subject is particularly timely since earlier this year NASA and ESA chose THREE missions to Venus for the coming years. Many of the workshop conveners and participants are involved in these missions, in particular in the ESa EnVision mission and the NASA Veritas mission but the NASA DaVinci mission is also represented.

Impression of the ongoing Workshop on Venus including remote participation

The Venus workshop had been postponed two times and the workshop and book project was finally launched adopting the new alternative scheme that ISSI had designed to better cope with COVID-19 Implications. The scheme starts the project off with an online meeting and has the in person meeting in the flow of the project when book chapters have been devised and/or (partly) written. The workshop is then used to discuss the chapters and their science content and the relations between chapters. We find this week that this works very well and motivates lively discussions. Because of COVID still being around the workshop is hybrid with about half of the participants joining remotely. We find that the investment in our state-of-the-art audio and video system pays off and eliminates some of the major disadvantages of hybrid meetings, such as discussion in the room cannot easily be followed from remote. If those speculating that the hybrid format will continue to be with us for some time are right then ISSI can say that it is well equipped for the task.

Also, in this month of September we will resume the Game Changers Online Seminar series with a talk on Venus Exploration by Richard Ghail from the University of London, one of the masterminds of the ESA EnVision mission. The program until the end of the year is still under development – we admit that we are a bit late – but should be in its final form by the end of this week. Stay tuned! We will cover a wide range of subjects from astrophysics and planetary science to climate change and astrobiology.

Of course, nobody can say with great confidence how the situation with COVID will evolve, in particular in Switzerland. But we hope that we can continue with our program even through coming the fall and winter. We have a set of rules at the institute and require visitors to be either vaccinated, recovered from the disease or negatively tested.

With my best regards


Tilman Spohn


The Hubble Space Telescope: 30 Years of Discovery, Symbol of Human Engineering

Tuesday, 28th September 2021, 18h CEST

Online Event (in French) with Prof. Roger-Maurice Bonnet, Honorary Director of the International Space Science Institute, director of research emeritus at the CNRS (Paris Institute of Astrophysics), former Scientific Director of ESA, member of the Royal Academy of Swedish Science, a honorary member of the AAE.

For thirty years Hubble, remains the largest space telescope in operation today, offering the most piercing and accurate look at the Universe and its evolution. Thanks to a series of five astronaut repair and maintenance missions from NASA and ESA, it now offers us the most beautiful images of the objects of the Universe, from the planets to the most distant galaxies, monstrous black holes, stars, from their birth to their end, revealing the astonishing acceleration of its expansion 4 billion years ago attributed to the mysterious dark energy. Thanks to astronomers around the world, it will go down in history as a magnificent achievement of human genius.

Registration for this event (Application open until September 27) >>


Understanding the Diversity of Planetary Atmospheres

Volume 81 in the Space Sciences Series of ISSI

Thanks to the observation of a growing number of planetary atmospheres, we are at the dawn of a major scientific revolution in atmospheric and climate sciences. But are we ready to understand what will be discovered around other stars? 

This book brings together 15 review chapters that study and provide up-to-date information on the physical and chemical processes that control the nature of atmospheres. It identifies commonalities between various solar system atmospheres, analyzes the dynamic processes behind different atmospheric circulation regimes, and outlines key questions remaining in solar system science.

This volume results from a Workshop organized at ISSI, on November 12-16, 2018, with the support of the Europlanet Research Infrastructure of the EU.

This volume is dedicated to the memory of Adam P. Showman, a creative thinker, brilliant scientist, pioneer and leader in the study of the diversity and dynamics of planetary atmospheres.

This book is edited by F. Forget, O. Korablev, J. Venturini, T. Imamura, H. Lammer, M. Blanc

This volume is co-published in Space Science Reviews in the Topical Collection “Understanding the Diversity of Planetary Atmospheres” (Partial Open Access) >>

Hard Cover Book >>

Prof. Dr. Maurizio Falanga is the new ISSI Administrative Director as of 1st of August 2021

The ISSI Board of Trustees and the University of Bern appointed Prof. Dr. Maurizio Falanga to serve ISSI as the new Administrative Director and at the University of Bern as Professor at the Physics Institute. Maurizio Falanga succeeds Rudolf von Steiger in these positions as of 1st of August 2021.

Prof. Dr. Maurizio Falanga

Maurizio Falanga was born in Basel, Switzerland and graduated in Theoretical Physics at the University of Basel. He received his PhD in Astrophysics at the University of Rome “La Sapienza”, Italy. Afterwards he held various research fellowship positions in astrophysics departments around Europe. His scientific background is in high-energy astrophysics (hot universe and compact objects). He is author and co-author of about 200 published papers and (co-)editor of several books in his research fields. He has been invited to serve on a number of high-level international committees like Board member of the A&A Journal and others. Since 2009 he is the science program manager at ISSI, and between 2013 and 2019 he has been appointed as the first part-time Executive Director of ISSI-Beijing, China. Thus, Maurizio is known to the ISSI community and is highly regarded as a friendly and open-minded person who is always approachable. ISSI is looking forward to working with Maurizio in his new function.



Prof. Dr. Rudolf von Steiger

Ruedi von Steiger, at ISSI since the first days of the institute in 1995, has retired from his position as Administrative Director and as Professor at the University of Bern by the end of July 2021. For ISSI’s science portfolio, Ruedi represented Solar and Plasma Physics with his own focus on the composition of the solar wind using theoretical modeling and data from Solar Composition Analyzers on space missions such as Ulysses. As the full-time administrative director, Ruedi was essential in running the institute and nurturing its growth from a few to almost a thousand visitors per year. Moreover, Ruedi was the institute’s link to the University of Bern for which he taught courses in Observational Cosmology, Nucleosynthesis, and Quantum Mechanics and served on the Faculty Board of the Faculty of Science. ISSI will forever be thankful to Ruedi for his tireless and inspirational service for more than 25 years.

“The Contemporary Global Carbon Cycle and the Impact of the COVID-19 Pandemic on CO2 Emissions” with Corinne Le Quéré  (University of East Anglia, UK)


Emissions of carbon dioxide (CO2) from human activities have caused the planet to warm and have set in motion a train of changes in the natural carbon cycle. Every year, the land and ocean natural carbon reservoirs, the so-called carbon ‘sinks’, absorb 55% on average of the CO2 emissions we put in the atmosphere from burning fossil fuels, deforestation, and other activities. The carbon sinks slow down the pace of climate change, but they respond themselves to a changing climate by leaving more CO2 in the atmosphere. The latest evidence on trends in emissions and sinks of carbon of the past 60 years reveals the limits of our understanding and the challenges we face to develop a planetary monitoring system that can keep track of the rapidly changing carbon cycle. The Covid-19 pandemic generated the need to monitor global emissions daily, something that was thought impossible before. From this need has arisen an explosion of new research methods on monitoring the carbon cycle. This presentation will provide a snapshot of current understanding and capacity to untangle changes in the Earth’s vital organic element: carbon.

Corinne Le Quéré is Royal Society Research Professor of climate change science at the University of East Anglia. She conducts research on the interactions between climate change and the carbon cycle. Her research has shown that climate change and variability affects the capacity of the Earth’s natural carbon reservoirs to take up carbon dioxide emitted to the atmosphere by human activities. Corinne Le Quéré instigated and led for 13 years the annual update of the global carbon budget, an international effort to inform global climate agreements. She was author of three assessments reports by the Intergovernmental Panel on Climate Change, which was awarded the Nobel price prize in 2007, and is former Director of the Tyndall Centre for Climate Change Research. Professor Le Quéré is Chair of France’s High Council on climate, an independent experts body that advises the French Government on its responses to climate change, and member of the UK Committee on Climate Change. She was elected Fellow of the UK Royal Society in 2016 and was appointed Commander of the Order of the British Empire (CBE) in 2019 for services to climate change science.

This webinar was recorded on July 22, 2021

Spotting Hard-To-Detect Coronal Mass Ejections from the Sun

Report from ISSI Team #415 Understanding the Origins of Problem Geomagnetic Storms led by N. V. Nitta and T. Mulligan

Coronal mass ejections (CMEs) are large eruptions from the Sun that are often powerful drivers of space weather effects at Earth. Being able to predict their behaviour in interplanetary space is one of the main goals of space weather forecasting. However, there is a class of CMEs that are particularly hard to observe and, therefore, forecast. These eruptions are known as “stealth CMEs” and they were first reported by Robbrecht et al. [2009], who used the twin STEREO spacecraft (in orbit around the Sun) that were separated by ~50° in longitude to observe a clear ejection off the solar limb from one perspective, but no corresponding eruptive signatures against the solar disc from the other. The lack of indications that an eruption has occurred makes it particularly challenging to establish whether a CME is Earth-directed, especially when imagery from secondary viewpoints is not available. Nitta & Mulligan [2017] analysed a number of stealth CMEs that, in fact, caused unexpected space weather effects at Earth, also known as “problem geomagnetic storms”.

New research from Palmerio et al. [2021] aims to explore techniques that may be useful to identify and analyse eruptions that are elusive when viewed against the solar disc. The authors revisited four well-known stealth CMEs that were characterised by off-limb observations from either one or both STEREO spacecraft, enabling knowledge of their approximate source region. They first applied different image-processing techniques to these events (see example in Figure 1), noting that the most prominent changes that can be attributed to eruptive signatures are evident in long-separation difference data (where to one image is subtracted a preceding one, from e.g. 12 hours prior). Once large-scale changes in the structure of the solar corona are singled out, more refined analysis using “plain” intensity images can be applied to interpret the identified structures, and data produced with more advanced processing techniques can be used to zoom-in on the source region and inspect the eruption in deeper detail.


Figure 1. Example of different image processing techniques applied to a stealth CME that erupted on 4 February 2012. The arrows in the last column point to the faint eruptive signatures (in terms of dimmings and brightenings) found in “plain” intensity images, difference images, and images processed with the wavelet packet equalisation and multi-scale gaussian normalisation techniques. Figure from Palmerio et al. [2021].

Since the events studied were characterised by two or three simultaneous observations of the Sun and its corona, the authors also applied several geometric techniques to reconstruct the eruptions in 3D and connect them to a more-or-less defined location on the solar disc (see example in Figure 2). They concluded that the efficacy of these methods strongly depends on the propagation direction of a CME with respect to the observers and the relative spacecraft separation, since it is not unusual for CMEs to deflect in latitude and/or longitude when they are only a few solar radii away from the surface.


Figure 2. Example of different geometric techniques applied to the same stealth CME shown in Figure 1, which erupted on 4 February 2012. The top row shows reconstructions applied to solar disc imagery using the tie-point technique, the middle row shows reconstructions applied to coronagraph data using the graduated cylindrical shell model, and the bottom row shows results from both methods. Figure from Palmerio et al. [2021].

The careful, multi-step analysis presented in Palmerio et al. [2021] suggests that stealth CMEs can in principle be successfully identified even if they look “invisible” at first glance, thus allowing their inclusion in space-weather forecasting models and predictions.


More information can be found here: “New method predicts ‘stealth’ solar storms before they wreak geomagnetic havoc on Earth” >>



Nitta, N. V., and Mulligan, T.: Earth-affecting Coronal Mass Ejections without Obvious Low Coronal Signatures, Solar Physics, 292:125. doi:10.1007/s11207-017-1147-7, 2017.

Palmerio, E., Nitta, N. V., Mulligan, T., Mierla, M., O’Kane, J., Richardson, I. G., Sinha, S., Srivastava, N., Yardley, S. L., and Zhukov, A. N.: Investigating remote-sensing techniques to reveal stealth coronal mass ejections, Frontiers in Astronomy and Space Sciences, 8:695966, doi:10.3389/fspas.2021.695966, 2021.

Robbrecht, E., Patsourakos, S., and Vourlidas, A.: No Trace Left Behind: STEREO Observation of a Coronal Mass Ejection without Low Coronal Signatures, The Astrophysical Journal, 701, 283–291, doi:10.1088/0004-637X/701/1/283, 2009.

“Testing the Massive Black Hole Paradigm with High Resolution Astronomy” with Reinhard Genzel (Max Planck Institute for Extraterrestrial Physics, Garching, Germany)

The discovery of the Quasars in the 1960s led to the ‘massive black hole paradigm’ in which most galaxies host massive black holes of masses between millions to billions of solar masses at their nuclei, which can become active galactic nuclei and quasars when they accrete gas and stars rapidly. I will discuss the major progress that has happened in the last decades to prove the massive black hole paradigm through ever more detailed, high resolution observations, in the center of our own Galaxy, as well as in external galaxies and even in distant quasars. In the Galactic Center such high resolution observations can also be used to test General Relativity in the regime of large masses and curvatures.
Reinhard Genzel is an infrared- and submillimetre astronomer. He and his group are also engaged in developing ground- and space-based instruments for astronomical observations. They use these to track the motions of stars at the centre of the Milky Way around Sagittarius A*, and showed that these stars are orbiting a very massive object, now known to be a black hole. Genzel and his group are also active in studies of the formation and evolution of galaxies and active galactic nuclei. Reinhard Genzel was awarded the 2020 Nobel Prize in Physics (jointly with Andrea Ghez and Roger Penrose) “for the discovery of a supermassive compact object at the centre of our galaxy”.
Genzel had studied at Freiburg University and Bonn University, finishing his PhD in 1978 at the Max Planck Institute for Radio Astronomy in Bonn. As a postdoc he worked at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts; he was a Miller Fellow, then Associate Professor and in 1981 he became Full Professor in the Department of Physics at the University of California, Berkeley. In 1986, Genzel became director at the Max Planck Institute for Extraterrestrial Physics in Garching (near Munich) and in 1988 also Honorary Professor at Ludwig-Maximilians-Universität München. From 1999 to 2016, he had a joint appointment as Full Professor at the University of California, Berkeley, where he is now emeritus professor. Prior to the Nobel prize, Reinhard Genzel had received numerous awards, among them the Herschel Medal of the Royal Astronomical Society (2016), the Tycho Brahe Prize of the European Astronomical Society (2012) and the Karl Schwarzschild Medal of Astronomische Gesellschaft (2011).

This webinar was recorded on July 15, 2021