A new way of understanding the Universe
Dr Laura Nuttall, Senior Lecturer in Gravitational Waves, is working on ways to detect colliding black holes deep in space
Imagine if you could listen to the Universe. Out there in space, huge black holes are colliding to produce even bigger black holes. When they do, they create massive ripples in space-time that travel across the cosmos.
Cosmologists know these ripples as gravitational waves. But what do they sound like and how can we hear them? We know that finding the answers will help us better understand our Universe.
Dr Laura Nuttall, a Senior Lecturer in our Institute of Cosmology and Gravitation is involved with an international project called the Laser Interferometer Gravitational Wave Observatory (LIGO), and is listening to the sounds of the Universe.
‘By studying them, we can try and understand what properties black holes have; what these objects really are. I’m trying to understand where we are in the Universe, how we got to be here and what’s going to happen.’
Unlocking hidden secrets of the Universe
In the US, two giant microphones called interferometers are powerful enough to detect gravitational waves. Laura is one of the scientists around the world who share LIGO’s data.She’s making the most of what the very latest technology offers, to glimpse the true nature of cosmic mysteries: phenomena like neutron stars or black holes that are tens – or even hundreds – of times the size of our sun.
Laura explains, ‘By studying them, we can try and understand what properties black holes have, what these objects really are. I’m trying to understand where we are in the Universe, how we got to be here and what’s going to happen.’
Gravitational waves were first detected in 2015. That’s how recently tech enabled us to hear them for the first time. Already, they’re allowing us to see the true nature of black holes and neutron stars – awe-inspiring objects created at the moment a massive star dies.
‘We want to know where is this happening, what’s the physics that’s going on? What’s the size limit of a neutron star? Better understanding of neutron stars could help us understand the nuclear processes of atoms. Which could really impact us here on Earth.’
A black hole or neutron star is formed when a star collapses in on itself, but what happens when two of these objects collide?
‘When these entities are colliding, we expect them to create even bigger black holes or potentially bigger neutron stars. Although neutron stars are so dense, they can only get so big before gravity becomes so strong that it will rip space time apart and create a black hole,’ Laura explains.
Back in 2015, gravitational waves were only observed monthly. But, as the detectors become more sensitive, Laura and her colleagues can see deeper into the Universe. As they pick up more sources, they now see waves on an almost weekly basis. Within years, they may see waves daily.
Laura describes what the scientists hope to do with the data on these collisions, ‘We want to know where this is happening, what’s the physics that’s going on? What’s the size limit of a neutron star? Better understanding of neutron stars could help us understand the nuclear processes of atoms. Which could really impact us here on Earth.’
Going back to the beginning
As the LIGO detectors get more sensitive and new interferometers come online in other countries, triangulation will become easier. This will reduce the field of view to that of conventional telescopes – a huge step forward.
A space based gravitational wave observatory will be launched in the 2030s by the Laser Interferometer Space Antenna (LISA). Eliminating all the Earthly noise will mean much clearer detection of gravitational waves, unlocking the potential to see back to the very early Universe. And possibly the creation of black holes.
‘We’re really at the very beginning of finding out what we can learn with gravitational waves and there is so much more to discover,’ says Laura.
Understanding these things could help unlock the hidden secrets of the Universe. We could be on a journey to discover our true place in existence.