Context. With the most recent Gaia data release, the number of sources with complete 6D phase space information (position and velocity) has increased to well over 33 million stars, while stellar astrophysical parameters are provided for more than 470 million sources, and more than 11 million variable stars are identified. Aims. Using the astrophysical parameters and variability classifications provided in Gaia DR3, we selected various stellar populations to explore and identify non-axisymmetric features in the disc of the Milky Way in configuration and velocity space. Methods. Using more about 580 000 sources identified as hot OB stars, together with 988 known open clusters younger than 100 Myr, we mapped the spiral structure associated with star formation 4'5 kpc from the Sun. We selected over 2800 Classical Cepheids younger than 200 Myr that show spiral features extending as far as 10 kpc from the Sun in the outer disc. We also identified more than 8.7 million sources on the red giant branch (RGB), of which 5.7 million have line-of-sight velocities. This later sample allows the velocity field of the Milky Way to be mapped as far as 8 kpc from the Sun, including the inner disc. Results. The spiral structure revealed by the young populations is consistent with recent results using Gaia EDR3 astrometry and source lists based on near-infrared photometry, showing the Local (Orion) Arm to be at least 8 kpc long, and an outer arm consistent with what is seen in HI surveys, which seems to be a continuation of the Perseus arm into the third quadrant. The subset of RGB stars with velocities clearly reveals the large-scale kinematic signature of the bar in the inner disc, as well as evidence of streaming motions in the outer disc that might be associated with spiral arms or bar resonances. A local comparison of the velocity field of the OB stars reveals similarities and differences with the RGB sample. Conclusions. This cursory study of Gaia DR3 data shows there is a rich bounty of kinematic information to be explored more deeply, which will undoubtedly lead us to a clearer understanding of the dynamical nature of the non-axisymmetric structures of the Milky Way.@en

Mitigating the adverse effects of climate change requires us, globally, to speed up the energy transition: to decarbonise energy supply while maintaining the security of supply and the affordability of energy services. This is an unprecedented challenge. The energy transition seems to have moved into a phase of scaling up: technologies are becoming competitive; more and more of the public will have to be involved in the energy transition in the coming years. In this report, we outline the opportunities that come from studying so-called ‘emergent behaviour’ in the energy transition. Emergent behaviour are trends or patterns observed on the aggregated/system level that are not a simple sum of the individual actions. What drives behaviour is hard to anticipate, but understanding it is crucial for a successful energy transition – to avoid lock-in and delays. As such, this report outlines what the concepts emergence and complexity theory can entail for the energy transition, what approaches there are to study this, and how to translate this into action. We focus on how we may be able to anticipate how such behaviour (i.e., opinions, choices and using) of larger societal groups may promote or hamper progress in the energy transition. And, at the end of the day, how to affect those processes to scale up a fair, inclusive energy transition robustly. Based on literature and interviews, we provide five perspectives: 1) behaviour in the energy transition, 2) the transformation of large systems, 3) emergent behaviour and marketing, 4), modelling emergent behaviour, and 5) intervening to shape complex systems. There are substantial opportunities to better develop, study and integrate concepts from complex systems and energy systems research and modelling into decision-making processes for the energy transition. We present a research agenda including a concrete action plan for the following research challenges: behavioural theory and modelling of the energy transition, 2) anticipating emergent behaviour to scale up the energy transition, 3) developing transition narratives, and 4) embracing key/change agents and emergent leadership. The action items vary between quick wins and fundamental research ideas that may, together, help us to better shape the energy transition.@en