Belgian researchers propose a gravitational wave detector on the Moon

 Sylvie Claire / Mars 24, 2021

An international scientific team, including researchers from UCLouvain and ULiège, proposes to install a gravitational wave detector on the Moon. The conclusions of their study are published in the magazine The Astrophysical Journal.

Although predicted more than a century ago by Albert Einstein's theories, gravitational waves were only observed for the first time in 2015. They are tiny jolts caused in the fabric of space-time by the collision of celestial elements, such as black holes or neutron stars. Their detection requires sophisticated ultra-sensitive instruments. As a complement to terrestrial telescopes, the researchers' idea is to make the Moon itself a detection element by exploiting its response to gravitational waves. We submitted this concept in response to recent calls from ESA and Nasa as an idea for a future lunar science mission, and we intend to turn this exciting concept into reality, says Jan Harms, a professor at the Gran Sasso Science Institute, who heads a team of more than 80 scientists from Italy, Belgium, the Netherlands, Denmark, the United States, Switzerland and the United Kingdom, gathered in the Lunar Gravitational Wave Antenna (LGWA) project, in a statement. The idea of detecting gravitational waves on the Moon is not new.

In the early 1970s, the American physicist Joseph Weber had already suggested it. A lunar surface gravimeter was deployed in 1972 on the Moon, by the Apollo 17 mission, in order to observe lunar vibrations caused by gravitational waves, but without success. The UCLouvain is currently manufacturing the first prototypes of a core detector: the seismometer. It will be the most sensitive sensor in the world that will work in cryogenic conditions, explains Joris van Heijningen, researcher at UCLouvain and collaborator of the project. The researchers hope that the new technologies available and the favorable conditions at the Moon's south pole will pave the way for groundbreaking discoveries, making it possible to see signals from compact binaries composed of galactic white dwarfs to massive black holes at high redshift. At the same time, the seismic sensors of the Lunar Gravitational Wave Antenna, developed with the help of the University of Liege, could make it possible to observe lunar seismic events with unprecedented precision. And thus to know more about the internal structure of our natural satellite or about the history of its formation