College of Agriculture, Engineering
and Science (CAES)

UKZN Scientist Makes Waves with Tidal Forces Research

Professor Rituparno Goswami, associate Professor and academic leader of Research in the School of Mathematics, Statistics and Computer Science (SMSCS) and a member of the Astrophysics and Cosmology Research Unit, was featured in the Massachusetts Institute of Technology’s Technology Review magazine for research conducted with Professor George Ellis of the University of Cape Town on the generation of gravitational waves.

The research featured in the publication marks a significant advance in the understanding of gravitational waves, first suggested in Einstein’s theory of general relativity and the direct observation of which was first announced by a team of physicists in 2016 after the effects of the collision of two black holes on the fabric of space time were recorded using a state-of-the-art network of detectors.

Delving into Newton’s Laws, the article on the research explains the gravitational forces that objects generate and how gravitational forces vary with distance, and articulates how Goswami and Ellis’s investigation highlights that Newton’s work did not account for the speed of light.

Goswami and Ellis’s research suggests that since nothing can move faster than the speed of light – not even the force of gravity – and the moon’s gravitational forces will take time to reach the earth and exert an influence on the oceans – another force must be at work on the planet’s tides: that of gravitational waves. They propose that gravitational waves are hidden but evident in tidal forces.

The scientists say tidal forces are a form of gravitational radiation, behaving as waves in a manner consistent with the theory of general relativity. They set out to demonstrate, mathematically, that tidal forces exhibit the same properties as gravitational waves, concluding that tidal forces are essentially low-frequency gravitational waves. This effect is, in principle, measurable, and indicates that the effects of gravitational waves are more visible in everyday phenomena than may previously have been known.

‘This is an incredible achievement,’ said Professor Sudan Hansraj of the SMSCS. ‘The discovery of a connection with tidal forces or Weyl stresses is an amazing feat of creativity, ingenuity and insight.’

A gravitational physicist; Goswami has been part of UKZN since 2013, having previously conducted research at the University of Cape Town and the University of Alberta in Canada after completing his studies in his native India.

Words: Christine Cuenod

Photographs: ESO/L. Calçada/M. Kornmesser and supplied