Einstein Telescope, the Netherlands opens to collaboration with Italy

The Netherlands has reopened the European game to host the Einstein Telescope, the future gravitational wave detector, showing openness to collaborate with Italy. Dutch Minister of Education, Culture and Science Rianne Letschert has tasked the project office with evaluating a possible collaboration with Italy, which has proposed Sardinia as a site. This would mark a shift from the initial hypothesis of a single triangular detector, opening the door to a double L configuration with two sites in different countries.

The new hypothesis involves two L-shaped detectors, each with 15-kilometer arms, located in two nations. Italy had already expressed a preference for this solution, provided it hosts one of the two detectors in Sardinia. The President of the Sardinia Region, Alessandra Todde, hoped for "the broadest possible agreement," calling the path initiated months ago with Saxony, which had already signed an agreement with Sardinia for this configuration, correct.

The Sardinian site of Sos Enattos in Lula (Nuoro) is recognized by the scientific community as one of the most suitable in Europe due to its geophysical characteristics, with extremely low levels of seismic and anthropogenic noise. According to experts like astrophysicist Marica Branchesi, the double L configuration could offer the greatest scientific benefits for the project.

The Einstein Telescope is the most ambitious project in European physics since the CERN supercollider LHC in Geneva. It is a future gravitational wave detector, designed to observe the ripples in spacetime predicted by Albert Einstein in his theory of general relativity and first observed only in 2015. The project stems from the need for more sensitive instruments to study these cosmic phenomena.

From the project's inception, the scientific community has considered two possible configurations: a single triangular-shaped detector with 10-kilometer sides, or a dual-L configuration with two separate detectors in different countries, each with 15-kilometer arms. Italy officially submitted its candidacy in 2023, proposing the former Sos Enattos mine in Sardinia as an ideal site due to its unique geophysical characteristics.

The international competition intensified when Germany also expressed interest, evaluating proposals in Saxony and Maastricht. By 2026, Saxony had already signed an agreement with the Sardinia Region for the dual-L configuration. Now, the Dutch opening could lead to a truly European solution, with two sites that would maximize the telescope's scientific capabilities.