The international team led by researchers at the Swinburne University of Technology and CSIRO combined telescope and gravitational wave data in an attempt to unlock the true value of the Universe’s expansion, called the Hubble Constant.

Knowing how fast the Universe is expanding is extremely important, as it helps determine how large or far away objects are, the role of dark matter in the evolution of the Universe, as well as the Universe’s origin and ultimate fate.

The dramatic collision of two neutron stars, which was visible to telescopes and caused a gravitational wave to be detected on Earth, provided an opportunity for the team to take this new measurement of the Hubble Constant.

The collision between these neutron stars was so powerful that it produced gravitational waves whilst also sending jets of energetic particles into space, which was essential for making the measurement.

The jets are launched for only a couple of seconds, but slamming into the surrounding gas caused them to glow for months afterwards. The team analysed almost a year’s worth of observations from the Hubble Space Telescope, NRAO’s VLA and the European VLBI.

By combining all the data, the team revealed a new value for the Hubble Constant which is more accurate than previous attempts made using gravitational waves. This is the strongest indication yet that gravitational waves could settle the debate on the value of the Hubble Constant.

Nobel Prize winner for his research into the Universe’s expansion, Professor Brian Schmidt, said that the precision the team has managed to get out of a single option is quite impressive.

Read more in The Conversation article by lead researcher, Dr Kelly Gourdji.
Two golden balls, representing the neutron stars, are shown colliding. A telescope dish is in the foreground.

An artists conception of the GW170817 afterglow observed by a single dish from the U.S. National Science Foundation NRAO Very Large Array. The jet of material launched away from the merging neutron stars causes a radio glow as it interacts with the surrounding gas, which moves with time across the sky. Image Credit: Carl Knox/OzGrav/Swinburne University of Technology

An artists conception of the GW170817 afterglow observed by a single dish from the U.S. National Science Foundation NRAO Very Large Array. The jet of material launched away from the merging neutron stars causes a radio glow as it interacts with the surrounding gas, which moves with time across the sky. Image Credit: Carl Knox/OzGrav/Swinburne University of Technology