News

Primordial back Holes could explain dark matter

Recently, the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) might have  have  observed a stochastic background of gravitational waves through the distortion they cause in the repeated signals arriving at earth from  millisecond pulsars. Gravitational waves, ripples of the fabric of space-time, have been predicted by Einstein himself within his theory of General Relativity. Every time the space-time is perturbed, such gravitational waves propagate like sound waves propagate after plucking the strings of a violin. 

Scientists from the Department of Theoretical Physics (DPT) of the University of Geneva offer a theoretical explanation about the origin of such stochastic background of gravitational waves which could be due to primordial black holes. Upon their creation at the dawn of time after the Big Bang, these black holes, typically as heavy as an asteroid, would have perturbed the fabric of space time, leaving behind gravitational waves free to propagate to us.

Intriguingly, such primordial black holes are might  themselves account for the mysterious substance known as dark matter. As such, this  possibility does not invoke   exotic explanations, primordial black holes are indeed made of the same ordinary matter we are familiar of. If the stochastic background of gravitational waves seen by the NANOGrav is indeed due to primordial black holes, the future space-based telescope LISA, in which members of the DPT are involved, should also observe such a signal, making the whole hypothesis testable in the near future. 

 

February 9, 2021
  News