Pro ISSI Talk

The James Webb Space Telescope (JWST) is one of the most ambitious scientific mission ever flown, over 100 times more sensitive than its predecessor, the Hubble Space Telescope.

JWST has been designed to answer outstanding questions about the Universe and to make breakthrough discoveries in ALL fields of astronomy. Accessible to the scientific community worldwide, Webb is designed and built to offer scientists the capabilities needed to push the frontiers of knowledge of our own Solar System, of the formation of stars and planets, including planets outside our Solar System (exoplanets), and of galaxy assembly and evolution, in ways never before possible. 

Webb is observing the Universe in the near-infrared and mid-infrared. It carries a suite of state-of-the-art astronomical instruments capable of addressing a very broad spectrum of outstanding problems in astrophysics. The instrument complement includes powerful cameras, spectrographs, and coronagraphs, designed specifically to observe faint objects and structures in close proximity to very bright celestial targets.  The telescope was launched on December 25, 2021 on an Ariane 5 rocket from Europe’s Spaceport in French Guiana, from where it embarked on a month-long journey to its final orbit about one and a half million kilometres from Earth, at what is called the second Lagrange point or L2. In the first three weeks after launch, Webb unfolded its five-layered sunshield, and deployed its  gold coated beryllium 6.5-metre primary mirror.  The launch and deployment were executed flawlessly and after a few months  of telescope and instrument verifications, the observatory was ready for science. The speaker will review these very first phases in the mission, the early excitement of realizing that, from the first data received, the observatory  performance was already exceeding the expectations of its designers and builders. One year later, JWST is producing a steady stream of breakthrough results in all field of astrophysics. The speaker will review the most significant recent  highlights and show how JWST is already changing the way we see the Universe.

Pro ISSI talk was recorded on November 1, 2023

“Do there exist many worlds, or is there but a single world? This is one of the most noble and exalted questions in the study of Nature.”

Albertus Magnus (circa 1200–1280)

Are there other worlds in the universe? Does life exist elsewhere in the cosmos? The technology of our time has made it possible to transform this dream of antiquity into a fascinating field of current astrophysics.

Three decades after the discovery of a first planet orbiting a star like our Sun, a few thousand planetary systems have been discovered. These first discoveries revealed to us the astonishing diversity of these systems, very different from our solar system: orbital periods of a few hours, planets with very high eccentricity, ocean planets, rocky or gas giant planets with sometimes retrograde orbits, etc.

After the euphoria of these first discoveries, the era of studying the atmospheres of exoplanets is now beginning. Fascinatingly, despite the enormous contrast between the high luminosity of the star and the very weak light that is emitted by the planets, the analysis of their atmospheres begins now. It will benefit from space telescopes and giant telescopes on the ground (up to diameters of 39 m).

Does life exist in other places in the cosmos? – Vertiginous question – The analysis of planetary atmospheres may reveal biosignatures, these spectral characteristics induced by the development of life. Advances in spectroscopy studies of exoplanets make us think that the search for extraterrestrial life is possible.

This Talk was recorded on May 24, 2023

The magnetic field is fundamental to solar activity and shapes the interplanetary environment, as shown by the full three-dimensional monitoring of the heliosphere provided by measurements from many past and present interplanetary and remote sensing spacecraft. Magnetic fields are also the source for coronal heating and the very existence of the solar wind; produced by the sun’s dynamo and emerging into the corona, magnetic fields become a conduit for waves, act to store energy, and then propel plasma into the Heliosphere in the form of Coronal Mass Ejections (CMEs). Magnetic fields are also at the heart of the generation and acceleration of Solar Energetic Particle (SEPs) that modify the space weather environment of the Earth and other planets.

Parker Solar Probe (PSP)’s launch in 2018, followed by Solar Orbiter (SO)’s launch in February 2020 have opened a new window in the exploration of solar magnetic activity and the origin of the Heliosphere. The first direct measurements of the plasma in the closest atmosphere of our star have already produced significant surprises, including the presence of folds in the magnetic field called switchbacks that come in patches, the prevalence of the bursty phenomenon known as magnetic reconnection together with turbulence in the outer corona and accelerating solar wind.

Marco Velli is the Johannes Geiss Fellow 2022 and Professor of Space Physics at the Earth, Planetary and Space Sciences Department, University of California, Los Angeles, USA. A student of the University of Pisa and Scuola Normale Superiore, he has spent research periods at the University of St. Andrews, Scotland, the Observatoire de Paris, France, Università della Calabria, Italy, and the Smithsonian CfA, Cambridge, MA, as well as the Jet Propulsion Laboratory, California Institute of Technology, where he remains a Senior Scientist.

This Pro ISSI Talk was recorded on March 15, 2023

More than three decades ago the late Johannes Geiss started to think about creating a new kind of institute where the space science community could work together. It would be tasked with contributing to a deeper understanding of the results from space research missions, adding value to those results through multi-disciplinary research in an atmosphere of international cooperation. By using his characteristic enthusiasm and perseverance he managed, together with a small group of Swiss colleagues and against all odds, that ISSI could open its doors in 1995 with a workshop on The Heliosphere in the Local Interstellar Medium.

The early years of ISSI were marked by steady growth, but also by threats that potentially endangered its very existence. Thanks to skillful politics and a growing standing in the community these could be fenced off, so when Johannes Geiss stepped down after eight years the growth continued to reach the current level of nearly a thousand visitors per year. Thanks to this strength it was possible to survive the years of pandemic nearly unharmed, so 26 years later a second workshop on the heliosphere could be convened, highlighting the tremendous progress that had been achieved in the field.

Using the two workshops as a bracket Rudolf von Steiger reviews the genesis and evolution of ISSI, highlighting a few events, results, and reminiscences here and there, and end with a subjective view of what it was that made ISSI a success.

Pro ISSI Talk was recorded on 2nd November 2022

with Thomas Schildknecht, Astronomical Institute, University of Bern, Switzerland

Abstract: The proliferation of space debris and the increased probability of collisions and interference raise concerns about the long-term sustainability of space activities, particularly in the low-Earth orbit and geostationary orbit environments. During recent years the number of satellites launched to space increased by orders of magnitude in particular due to costs reductions enabled by miniaturization and rideshare launch opportunities, as well as due to the deployment of so-called megaconstellations by private actors. In order to allow for safe operations in near-Earth space, and to ensure sustainable use of this unique resource, numerous measures are urgently needed. These include inter alia the prevention of collisions, the obligation to remove all objects after the end of their mission from the environment, active removal of existing debris, and international efforts to coordinate the traffic and manage the debris environment.

Governments, space agencies and civilian research organizations increase their efforts to build space object catalogues and to investigate the space debris population in different orbit regions. Understanding the nature and the sources of debris is a prerequisite to provide the scientific foundation for a sustainable use of near-Earth space.

Current space debris research activities to detect and characterize space debris at the Swiss Optical Ground Station and Geodynamics Observatory Zimmerwald will be illustrated with examples from the long-standing observation programs of the Astronomical Institute of the University of Bern (AIUB).

Pro ISSI Talk was recorded on May 11, 2022

The Indian Ocean rim is home to one third of the world’s population, mostly living in developing countries with low-lying coastal areas that are vulnerable to climate change. Satellite and in-situ observations detected a distinct spatial pattern of sea-level rise over the Indian Ocean in the past few decades. While many factors can induce sea level change (e.g., thermal expansion, land ice melting), this pattern is primarily caused by changes in wind-driven ocean circulation. Overlying the trend pattern, there are significant interannual-to-decadal variations.
During the recent global surface warming “hiatus” decade (2003 to 2012), the Indian Ocean stored 2/3 of the excess heat in Earth’s climate system, due to the enhanced mass and heat transports of the Indonesian Throughflow from the Pacific into the Indian Ocean.
A large portion of this extra heat was stored in the southeast Indian Ocean, which increased sea level, intensified marine heatwaves and aggravated coral bleaching near the Australian coasts. The interplay between global sea level rise due to anthropogenic warming, regional sea level rising pattern, and natural decadal variability contributed to the increased frequency and intensity of extreme sea level events along Indonesian coasts during 2010 to 2017, posing increased challenge to Indonesia.

This Pro ISSI Talk was recorded on November 24, 2021

Pro ISSI Talk 1: “Super-Earths, Mini-Neptunes and the Radius Valley in Extrasolar Planets” – Talk with Julia Venturini (ISSI, Bern, Switzerland)

Abstract: The NASA Kepler Satellite has discovered more than 2300 extrasolar planets. This has revealed that in the size distribution of extrasolar planets, there is a depletion of planets with a size of about 1.7 Earth radii. This “Radius Valley” separates rocky super-Earths from volatile-rich mini-Neptunes. It stands as one of the most important observational constraints to understand the origin and composition of exoplanets with radii between that of Earth and Neptune. This talk will first provide an introduction to the topic of exoplanets with a speciasl focus on super-Earths and mini-Neptunes. Then, it will describe several important physical mechanisms that can explain the radius valley, including a recent combined formation and evolution model that was developed in Bern. 

Pro ISSI Talk 2: “Origin of the Regional and Interannual Variability in Sea Level” – Talk with Lorena Moreira (ISSI, Bern, Switzerland)

Abstract: Satellite observations of the Earth have shown that the global mean sea level is rising, even in an accelerating fashion. They have also revealed important regional differences in the rates of sea level rise. While the origin of the global mean sea level rise is now well known (anthropogenic global warming), the causes of the regional variability are less well understood. The first part of the talk will focus on the phenomena that are suspected to cause the observed regional trend patterns in sea level. Current knowledge is that the regional variability is mostly driven by the natural climate variability. Then, the interannual fluctuations will be discussed which is important to better estimate the acceleration of the global mean sea level rise, which is key for the understanding of the future evolution of the sea level.

Pro ISSI Talks were recorded on May 12, 2021.

“CHEOPS – the CHaracterizing ExOPlanet Satellite”

Pro ISSI talk with Andrea Fortier, Instrument Scientist, CSH (CHEOPS), University of Bern , Switzerland

In 1995, two Swiss astronomers discovered the first exoplanet around a solar-like star. Since then, ground and space surveys have discovered more than 4000 exoplanets and the number continues to increase. The diversity seen in their masses, radii and orbital characteristics has opened a new and dynamical community in astronomy: the exoplanetary science. With a critical mass of researchers in a large variety of topics and a statistically significant number of confirmed objects, the time for the characterisation of these new worlds has come: what is their composition?, how do they form?, could they harbour life?

In December 2019, with the aim of finding hints to answer these questions, the CHaracterising ExOplanet Satellite (CHEOPS) was launched from French Guyana. CHEOPS was selected in 2012 as the first ESA Small Mission, with Switzerland leading a consortium of 11 European countries. After three months of in-orbit commissioning, CHEOPS started its nominal operations at the end of March 2020 acquiring images that allow for precise measurements of the exoplanets’ radii through the transit photometry technique.

In this talk CHEOPS primary objectives, its goals and first scientific results are presented. Furthermore, an overview of the construction phase, the challenges faced while building a mission in a short time and the current operation of the satellite are a part of this talk.

This presentation was recorded on January 20, 2021.