The hot and energetic Universe and the search for elusive gravitational waves will be the focus of ESA’s next two large science missions. Both will bridge fundamental astrophysics and cosmology themes by studying in detail the processes that are crucial to the large-scale evolution of the Universe and its underlying physics.
The L2 mission, with a launch date somewhere around 2028, will address two key questions: how and why does ordinary matter assemble into the galaxies and galactic clusters that we see today, and how do black holes grow and influence their surroundings? Black holes, which lurk unseen at the centres of almost all galaxies, are regarded as one of the keys to understanding galaxy formation and evolution.
The L3 mission, scheduled for 2034, will study the gravitational Universe, searching for ripples in the very fabric of space-time created by celestial objects with very strong gravity, such as pairs of merging black holes. Predicted by Einstein’s theory of general relativity but yet to be detected directly, gravitational waves promise to open a completely new window on the Universe. It will require the development of a spaceborne gravitational wave observatory, or extreme precision “gravitometer”, an ambitious enterprise that will push the boundaries of current technology.