Understanding the origin and evolution of stars and galaxies, the physics of neutron star extreme matter, and testing relativity through gravitational waves.
Cosmology studies our Universe on the very largest scales: characterising how large groups of distant galaxies are arranged and explaining how these structures were generated by the Big Bang. Light from these galaxies, as well as the Comic Microwave Background light from the early Universe, has allowed cosmologists to build a coherent narrative of how our Universe has evolved into the night sky we see today. But light has its limitations. Some cosmic ingredients, like dark matter and dark energy, do not emit light and interact only through gravity. There is also a limit on how far away (how far back in time) we can ever see with light: about 380 000 years after the Big Bang, when the CMB was formed. Before this time, the Universe is so hot and dense that it is effectively opaque to light.
Gravitational waves offer an exciting new window into how the Universe evolves and what it is made of. Rather than measuring the light given off by distant galaxies, we can now measure the gravitational waves they emit. This allows us to detect dark objects such as black holes (that do not emit light) and could therefore help uncover the nature of dark matter and dark energy. Gravitational waves can also be used to look back much further in time (since they interact weakly with matter, the early Universe is effectively transparent for gravitational waves).
Just as Galileo's telescope expanded our view of the cosmos - revealing new and surprising features about our solar system - gravitational waves are now expanding our experimental reach in what will surely be new and surprising directions.
Cosmic events in the very early Universe, such as inflation and the formation of primordial black holes, can produce characteristic gravitational wave signals.
GWI members working on astrophysics and cosmology include:
(See Our Members for contact links)