 |
| Remains of a Type Ia supernovae (G299.2-2.9). Image Credit: X-ray: NASA/CXC/U.Texas/S. Park et al, ROSAT; Infrared: 2MASS/UMass/IPAC-Caltech/NASA/NSF. |
byANDY FLEMING
Australian astronomers have combined all
observations of supernovae ever made to determine that the strength of gravity
has remained unchanged over the last nine billion years.
Newton's gravitational constant, known as G,
describes the attractive force between two objects, together with the
separation between them and their masses. It has been previously suggested that
G could have been slowly changing over the 13.8 billion years since the Big
Bang.
If G has been decreasing over time, this would
mean that Earth's distance to the Sun was slightly larger in the past, meaning
that we would experience longer seasons now compared to much earlier points in
Earth's history.
But researchers at Swinburne University of
Technology in Melbourne have now analysed the light given off by 580 supernova
explosions in the nearby and far Universe and have shown that the strength of
gravity has not changed.
