Extrasolar planet, star cluster and nebula in outer space. (© mozZz - stock.adobe.com)
NOTTINGHAM, United Kingdom — Humans have looked up at the night sky and pondered what it all means for as long as we've been building fires and sketching crude drawings on cave walls. We've come a long way since those days, but many mysteries remain when it comes to space. Now, scientists at the University of Nottingham predict gravitational waves detected out in space in the future may provide answers to some of the universe's lingering questions.
In collaboration with an international team of scientists, Professor Thomas Sotiriou from the University of Nottingham’s Centre of Gravity has showcased the incredible accuracy of the space interferometer LISA (Laser Interferometer Space Antenna). LISA can observe gravitational waves and detect new fundamental fields out in the cosmos with unprecedented precision.
On a more detailed level, LISA is a space-based gravitational-wave (GW) detector the European Space Agency plans to launch in 2037. Study authors believe this launch will facilitate exciting new ways to explore and understand our universe.
“New fundamental fields, and in particular scalars, have been suggested in a variety of scenarios: as explanations for dark matter, as the cause for the accelerated expansion of the Universe, or as low-energy manifestations of a consistent and complete description of gravity and elementary particles. We have now shown that LISA will offer unprecedented capabilities in detecting scalar fields and this offers exciting opportunities for testing these scenarios,” says Professor Sotiriou, Director of the Nottingham Centre of Gravity, in a university release.
LISA will look at what's going on around black holes
So far, astrophysical observations of objects with weak gravitational fields and small spacetime curvatures have not yielded any compelling evidence of where these fields are. Study authors explain, however, that there is “reason to expect” General Relativity deviations (interactions between gravity and new fields) will appear much more prominently at large curvatures. With this expectation in mind, study authors believe the detection of gravitational waves will open the door for finding these mysterious fields.
Extreme Mass Ratio Inspirals (EMRI) — which refers to when a stellar-mass compact object (a black hole or neutron star) spirals into another larger black hole with a mass millions of times larger than that of the Sun — are a big target for LISA. Researchers explain that such events provide a golden opportunity to analyze the “strong-field regime of gravity.”
During an EMRI event, the smaller object cycles around the supermassive black hole tens of thousands of times before finally plunging in. Study authors explain this process creates long signals potentially allowing humans to detect very small deviations pertaining to both the Standard Model of Particle Physics and predictions linked to Einstein’s famous theory.
Moreover, the research team has developed a new way to model the signal, and for the first time ever, put together an extensive estimation of LISA's ability to detect scalar fields coupled with gravitational interactions. They also estimated how well LISA can measure how much of a scalar field the small body of the EMRI can carry.
Once it launches, LISA will focus on detecting gravitational waves by astrophysical sources, and function within a group of three satellites. This collective will orbit around the Sun, all while flying millions of miles away from each other.
The study is published in the journal Nature Astronomy.
