Metals, in particular iron and nickel, have been found in cometary dust by in-situ experiments on board the Giotto and Rosetta spacecrafts as well as in dust particles collected by the Stardust space probe. They essentially appear in silicate, sulfide and metal grains. Two Sun-grazing comets, the Great Comet of 1882 and C/1965 S1 (Ikeya-Seki), approached the Sun so close that dust grains vaporized, revealing lines of several metals, in particular FeI and NiI emission lines in the coma spectrum. However, it came as a surprise to find numerous FeI and NiI emission lines in high-resolution spectra of comets observed at large heliocentric distances, where the equilibrium temperature is far too low to allow sublimation of silicates and sulfides. Moreover the average NiI/FeI abundance ratio derived using a fluorescence model appears one order of magnitude higher than the Solar value. In this talk, I summarize this discovery and present some hypotheses to explain these unexpected results that indicate that constituents of the cometary nucleus or processes in the coma are still missing.

Giant planet upper atmospheres are the intervening regions between planetary weather layers below and their space environments above. As a result of their exceptionally rarefied nature, they are highly sensitive probes of the forcing exerted from below and above. In this Keynote talk I will introduce and discuss some of the latest results related to giant planet upper atmospheres. I will highlight topics such as the giant planet "energy crisis", a decades-old
problem in which the (non-auroral) upper atmospheres of all giant planets have been measured hundreds of Kelvin warmer than expected, and how Saturn's upper atmosphere is revealing the decay of its ring system into the planet.

Atmospheres are our main observation window into the physical and chemical properties of exoplanets. In recent years, observations at high spectral resolution have allowed several breakthroughs in terms of their composition, dynamics and climates. These results have revealed extreme phenomena such as high-speed winds, atmospheric escape or metallic rains, further stretching the amazing diversity of planets beyond our Solar System and establishing new promises for the characterisation of more Earth-like planets. I will review some of these recent results and discuss future prospects.

Over the past 15 years, our understanding of the processes that sculpted the inner Solar System has been in a state of flux. The 'classical model', -- which assumes that the rocky planets accreted in an orderly way from a continuous disk of rocky planetesimals -- systematically fails to match the small mass of Mars relative to Earth and the total mass and structure of the asteroid belt. New dynamical models have invoked different processes. In the Grand Tack model, Jupiter's large-scale migration clears out Mars' feeding zone. In the Early Instability model, the same zone is depleted by an early dynamical instability among the giant planets. In contrast, the Low-mass Asteroid belt model assumes that few planetesimals ever formed in the present-day asteroid belt or Mars region. Each model can reliably match the inner Solar System. Two new models invoke pebble accretion (rather than planetesimal accretion) as the dominant pathway for terrestrial planet growth. What remains to be understood is whether these models are consistent with all of the relevant physics of planet-forming disks and how they fit into the broader view of planet formation constrained by astronomical and cosmochemical measurements.

Towards the end of this decade, ISRO, NASA and ESA plan to send four missions to Venus. The first three demonstrate new technologies and address specific science questions. The fourth, EnVision, is different. Taking its cue from Earth Observation and Mars exploration, EnVision seeks to understand Venus ‘in the round’: how geologically active is Venus today, and what does that mean for the cycling of volatiles – especially water and sulphur dioxide – between the interior, atmosphere and clouds? What lessons does Venus hold for understanding Earth-sized planets generally? EnVision will inform our answers with a complementary suite of instruments designed to provide a holistic picture of our closest neighbour.

Scientific exploration and discoveries at the Moon enable learning about the origin of planetary bodies and life, and our position in the cosmos. The Moon also provides a potential first economic sphere beyond Earth and Low Earth Orbit (LEO) and could provide a first-off world location for sustained living to learn about the Solar System, prepare for future onward exploration and to help with addressing present day challenges on Earth.

ESA is contributing to and preparing for lunar science exploration over the coming decades, bringing together the vision and strong science and technological expertise of the European lunar community. A focus of the presentation will be updating on the findings and progress being made by ESA and its Member States in preparation for science at, on and from the Moon. Such preparations aim to address key outstanding science questions across multiple science fields and addressing the challenges for the next generation of sustained and responsible human and robotic exploration.

Key activities include science payload contributions to the upcoming first NASA CLPS flights, development studies of a European Large Logistic Lander (EL3) for lunar surface access and tools for crewed geological exploration. Several science mission themes and associated payload suite development studies are currently exploring: lunar In situ resource utilisation (ISRU) demonstration; prospecting for local resources at lunar polar regions and investigating the volatile history of the Moon; utilising the Moon as a natural laboratory to understand its surface-space environment and to investigate physical, geological and biological processes and effects under lunar conditions; utilising the radio-quiet lunar farside as a platform for observing the cosmos in the low-frequency range.

Juno has transformed our view of Jupiter through major discoveries about its interior structure, origin, and evolution; atmospheric dynamics and composition; magnetic dynamo; and polar magnetosphere. Juno’s extended mission began August 1, 2021 and includes new measurements that are enabled by Juno’s orbital evolution, addressing discoveries from the prime mission and new objectives that reach beyond the planet itself to the Galilean satellites and Jupiter’s enigmatic ring system. An overview of Juno’s discoveries that have changed our understanding of Jupiter and giant planets will be presented along with plans for Juno’s extended mission of to investigate Jupiter’s system.

Hot Jupiters were the first type of planet to be discovered around a Sun-like star, the first to have their atmospheres characterized, and the first to have measurements that constrained wind and temperature structures. While these big and bright planets are observationally favorable, they are also interesting laboratories of atmospheric physics under extreme conditions. While we have been working to model their 3D structure for two decades, there are still many complicated pieces of physics that challenge our efforts and prevent model predictions from fully matching observations. To accurately model these atmospheres in 3D, we must consider: clouds/hazes, molecular dissociation (of opacity sources and even hydrogen), magnetic effects resulting from thermal ionization, and how these all work in concert with the full atmospheric dynamics and radiative transfer. In this talk I will give a brief overview of where the field currently stands in addressing these challenges.

One of the most fundamental questions in planetary science today is the nature of the ambient climate of early Mars (Noachian-Early Hesperian): Was the ambient climate “warm and wet/arid”, as suggested by widespread phyllosilicates, higher erosion rates, enhanced crater degradation, valley networks, and open/closed-basin lakes? Or was the ambient climate “cold and icy”, as suggested by recent climate models, with occasional perturbations causing heating and melting of surface snow and ice, and runoff to produce the observed characteristics and features? Using the framework of these two ambient climate options, we will discuss how NASA Mars Perseverance Rover at Jezero Crater open-basin lake, CNSA Tianwen-1 Zhurong Rover at Utopia Planitia and the 2022 ESA-Roscosmos Rosalind Franklin Rover to Oxia Planum will help to address these issues.

Responding to the claim that intelligent life must be commonplace throughout the universe, the physicist Enrico Fermi famously asked, “Where is everybody?” With this conundrum, Fermi called attention to the fact that a universe teeming with intelligence would likely be obvious to us. To explain this 'great silence', scientists have hypothesized that life must pass a crucial technological threshold to colonize interstellar space. Some aspects of societal advancement appear to be self-defeating, or at least highly perilous. Can the absence of extraterrestrial contact inform our response to existential threats on our own planet, such as anthropogenic climate change? In this talk, SETI Institute artist-in-residence Jonathon Keats will discuss his efforts to creatively engage Fermi's paradox through the creation of a Library of the Great Silence where humans can collectively assess global conditions from a cosmic perspective. Drawing on this experience, Keats will consider the potential for artists and philosophers to apply SETI and astrobiology for the practical benefit of society.

It is often heard that planetary rings (PR) are local dynamical laboratories, important for understanding protoplanetary disks (PPD). While they are very different in profound ways, PR and PPD indeed do inform, illustrate, or complement each other, theoretically and observationally.

1) Con o senza gas? The most profound difference between PR and most PPD is that gas plays a critical role in most PPD and a very minor one in most PR. There are however important PPDs that lack gas (debris disks) in which there are PR connections in the areas of collisional cascades and small particle size distributions.

2) Fluid dynamics is fundamental to PR as it is to PPD; in PR the "fluid" pressure and viscosity are generated by very gentle collisions between cm-m size particles, acting like molecules in a dense gas. In PPD, the gas provides pressure and viscosity, but the viscosity is strongly dependent on the intensity of PPD gas turbulence - which is poorly understood and hard to observe.

3) Radial transport of mass and angular momentum is similar in PR and PPD: in PRs, collision-scale viscosity is analogous to molecular kinematic viscosity and there is not really any equivalent to turbulence. However, angular momentum in both PR and PPD can also be powerfully transported over longer ranges by gravitational effects, including spiral waves that obey the same physics.

4) In spite of various attempts to ignore it, the messy physics of collisional particle sticking and bouncing is important in both environments. The outcome of growth by sticking in PPD - that determines the path to planetesimal formation - depends critically on the intensity of turbulence, whereas in PR growth is limited by tidal forces.

5) Large scale radial structure (strong surface density fluctuations and empty gaps) is generated by gravitational torques associated with local or nonlocal large objects. In both PR and PPD, local gravitational instabilities may be important. There is abundant smaller-scale structure revealed by Cassini in Saturn's rings that we do not understand, that may lead to further insights.

6) PRs and PPDs are not closed systems - infall of matter from beyond the system, and loss of matter to the central object, are very important to the compositional and radial evolution of both systems. Indeed, infall may be our best constraint on the age of Saturn's rings, and also limit their lifetime.

7) Short timescales are surprisingly important. We see features in PR evolving before our eyes. Saturn's rings may be both geologically young AND short-lived. In PPD, the most youthful stages - still the least well observed or understood - may be the key to many of the puzzles of the meteorite record, planetesimal formation, and the path to planets.

Science communication and equal participation in scientific efforts is necessary to successfully connect science and society. In this presentation I will start with a historical overview of science communication models, and I will discuss how the evolution of these models led to the necessity of applying open science practices. Open science is an umbrella term which promotes democracy and transparency in research. It is vital that scientists, stakeholders, educators, students, and citizens, in general, collaborate to efficiently produce and disseminate scientific work. Open science enables widening participation where people from different levels and backgrounds can dynamically collaborate to enrich the results of a scientific project. Open science can provide a successful roadmap to bridge the gap between science and society. What are the different aspects of open science? How open can a scientific project be? What are the benefits and what are the challenges of performing open science in scientific research? The presentation will end with a discussion on strategies towards successful implementation of open science and emphasis will be given on planetary science related projects.

This lecture is jointly held by Eugenia Covernton, LeWiBo, and Marina Molla, teacher, and is organised by the Europlanet Diversity Committee. It will be an opportunity to hear the speakers' stories about the initiative ‘Lecturers without borders’ and their experiences with bringing these lectures and EPSC to schools to make planetary sciences more accessible to the wider society.

Description extracted from https://lewibo.org/:

"Lecturers without borders is a project launched by a group of international scientists. The headquarters of the project are in Paris and Munich. The creators of the project are scientists and university and school professors who use their travel opportunities (when attending scientific conferences, going on holidays, etc.) to give free outreach-lectures in local schools and universities. The main target is to inspire the high school students and to raise their motivation in learning science. As of today the project has already over 190 lecturers and can approach up to 8 000 schools in Europe and Asia."