The LIGO discovery of gravitational waves opened up a new window to the Universe: the era of gravitational astronomy has begun. The eLISA satellite constellation, planned for launch in 2030's, is in a new generation of gravitational observatories. It is sensitive enough to possibly observe gravitational waves orignating from the early Universe. This would give us an uprecedented direct view of the physics of the very early Universe.
Our group in Helsinki is in a unique position to make detailed theoretical and numerical studies of the processes which cause gravitational waves. The results will be important for the feasibility studies and detection strategy of eLISA. Correspondingly, eLISA becomes a "microscope" which can be used to exclude or support different physical processes which may have happened in the early Universe.