In 2015, gravitational waves were observed for the first time from the collision of two black holes a billion
light years away. Each black hole was about 30 times the mass of our Sun. Since this first observation, several
more mergers from binary black holes and also a binary neutron star have been observed by LIGO, the Laser
Interferometer Gravitational-wave Observatory in the U.S. and also by Virgo in Italy. However, the
gravitational wave ‘window’ on the Universe has only just been opened. Gravitational waves can also be
produced from black holes that are millions of times the mass of our Sun. To find these gravitational waves
we need a different approach where pulsars in our galaxy are used to create a detector on a galactic scale!
SPEAKER PROFILE
Dr Hannah Middleton is a postdoctoral researcher at the University of Melbourne and a member of the
Australian Research Council Centre of Excellence for Gravitational Wave Discovery (OzGrav). Hannah did her
PhD at the University of Birmingham, where she worked on how pulsar timing can be used to investigate the
massive black hole binaries that are thought to exist at the centres of some galaxies. At Melbourne she is
working on looking for gravitational waves from spinning neutron stars.
She is passionate about science communication with public engagement and has written articles for The
Conversation and is the editor-in-chief of the LIGO Magazine (www.ligo.org/magazine/).