Does Spacetime Form Memories?

Dr Colm Talbot of Caltech wins the Charlene Heisler* Prize.

Albert Einstein predicted that gravitational waves should permanently change spacetime – effectively imprinting a “memory”.

Former Monash University astronomer Dr Colm Talbot spends much of his time testing the theory – an effort which this week won him a prize from the Astronomical Society of Australia, the country’s peak professional body for astronomers.

Does spacetime have memories?

In his PhD thesis Dr Colm Talbot – formerly of Monash University, now at Caltech, created models to probe how binary black holes form, and developed a Bayesian code to better infer the properties of gravitational wave sources. The code quickly became a standard tool used by LIGO-Virgo research teams to classify the origins of detected black hole mergers.

His work tests the prediction arising from Einstein’s general theory of relativity that a gravitational wave form will permanently deform the fabric of spacetime, leaving behind a “memory”. His research yielded tools that are now being deployed by various teams engaged in the hunt for the first confirmed memory detection.

* Dr Charlene Heisler was an internationally renowned astronomer who moved to Australia in 1993 to work at the Anglo-Australian Observatory. She died in 1999 at the age of 37. The prize recognises a most outstanding PhD thesis in astronomy.