Cosmology and Astroparticle Physics

Our Research

Cosmology is the study of the birth and evolution of the Universe. Using a mixture of experiments, simulation and theory, researchers in the School  of Physics are investigating topics from the nature of dark matter and  dark energy to what happened during inflation, a burst of ultra-fast expansion in the early Universe.

Astroparticle physics is the study of elementary particles of astrophysical origin, and lies at the intersection of particle physics and astrophysics. We use a "cosmic laboratory" to reveal fundamental properties of matter, or to learn about astrophysical phenomena. Some of the key questions that are being addressed are:

  • Dark matter:
    Most of the matter in the Universe is dark matter.  We are leading a project to construct a laboratory 1 km underground in Stawell, Victoria, where we will run an experiment to directly detect these dark matter particles. We also work on indirect dark matter detection by observing the contribution of dark matter annihilation or decay to cosmic ray fluxes and related signals. In addition, we are strongly involved in the development of new elementary particle physics theories that incorporate dark matter particles.

  • Dark Energy:
    Why is the expansion of the Universe accelerating? We are developing new theories to understand this surprising acceleration. We are also working on a number of new cosmological probes to better understand the properties of Dark Energy.

  • Inflation and gravitational waves:
    What caused the burst of rapid expansion in the first moments of the Universe? We study relic radiation from the Big Bang, the cosmic microwave background, to search for the gravitational wave signature of inflation. We are also strongly involved in the emerging field of gravitational wave astronomy through membership in the LIGO collaboration.

  • Matter-antimatter asymmetry:
    The universe consists almost entirely of matter, with very little antimatter.  We study mechanisms that could have created this imbalance between matter and antimatter.