Latest gravitational wave detection helps scientists reveal the history of the stars
Writing in the journal Nature, Ilya Mandel, University of Birmingham Professor of Theoretical Astrophysics, has explained how the latest gravitational wave detected in January of this year could allow scientists to study the stars in the same that palaeontologists use fossilised remains to understand the history of life on Earth.
Gravitational waves are ripples in space-time caused by massive accelerating objects, such as black holes. Their signals precisely probe the ultra-strong gravity that is found in the vicinity of black holes created by dying stars, allowing scientists to determine the rate of mergers of black hole pairs and develop different theories for how these pairs come about.
Professor Mandel summarises scientists’ current thinking on black hole pairs. One scenario is that the two stars are initially far apart and are brought together as the expansion of one of the arts rips off the outer layers of its companion star, bringing the dense centres of each of the stars together.
A second scenario proposes that both stars begin close together and do not expand. Instead, rapid spinning causes nuclear fusion within the stars, resulting in the stars contracting as they evolve.
A third scenario theorises that the two black stars don’t start out life as a pair at all. Instead, long after the stars have collapsed into black holes, interactions with other stars might bring them into an orbit close enough to enable a merger that is driven by the emission of gravitational waves. Recent gravitational wave detections are even giving rise to more radical possibilities, including a proposal that the two black holes have a non-star origin and could instead have formed from variations in material density found in the early universe.
Professor Mandel believes advancements in the sensitivity of the Advanced LIGO detectors used to detect gravitational waves will allow scientists to detect mergers of pairs of dense objects in ever greater numbers. Such detections will provide scientists with a massive astrophysi¬cal data set to explore the lives – and deaths – of massive starts in the same way that palaeontologists have used fossilised skeletons to better understand the history of life on earth.
You can read the full article by clicking on the link below:
Stellar palaeontology – Ilya Mandel & Alison Farmer (PDF)