ET Symposia play a distinctive role in the life of the Einstein Telescope (ET). Compared with ET Annual Meetings, they are more open to external participants, offer a broader range of topics, and create valuable opportunities to expand the community around the project. This openness is especially important as ET becomes increasingly visible across Europe and worldwide, attracting growing interest from researchers, engineers, institutions, industry, policy stakeholders, and early-career scientists.
The Aachen programme reflected the wide scope of the project. Sessions covered the scientific potential of next-generation gravitational-wave observatories, detector technologies, site characterisation, infrastructure, computing, governance, sustainability, communication, education, and community development. The contribution list included 250 entries, and the total number of partcipants exceeded 500, showing the breadth and energy of the work now taking place across the ET ecosystem.
A strong focus was also placed on exchange and networking. Poster sparklers gave presenters the chance to introduce their work in a concise and dynamic format, while the poster session and prize highlighted the contributions of many researchers, including early-career members of the community. Alongside the scientific programme, the organisers prepared several social activities, including city tours and visits connected with ET Education Center in Kerkrade.
Aachen also offered a welcoming setting for the week: a central university venue, pleasant weather, and a lively atmosphere that supported both formal sessions and informal discussions. The meeting concluded with reflections on the progress achieved and a look ahead to the next gathering of the community, announced to take place in Prague.
We warmly thank the Local Organising Committee, RWTH Aachen University, all speakers, session chairs, poster presenters, and participants — both on site and online — for making the XVI ET Symposium a productive and inspiring week.
Next time the Einstein Telescope community will meet in Prague for the 5th ET Annual Meeting.
