Space-borne gravitational wave detector LISA a step closer
Gravitational wave detector LISA, which will be able to measure gravitational waves in space using Dutch technology, has made a significant step forward. Earlier in 2017, an international group of scientists and institutes proposed LISA as a gravitational wave mission of the European Space Agency (ESA) in 2034. Other proposals were not submitted to ESA. This month Dutch institutes, including Nikhef, formally informed ESA that they support the LISA proposal.
The submitters of the LISA proposal include Gijs Nelemans (Radboud University) and Elena Rossi (Leiden Observatory), the Dutch research institutes SRON, Nikhef and TNO, and the research school NOVA. In early March, SRON submitted a letter of endorsement on behalf of the Dutch institutes to ESA in which it stated that they are willing to contribute to the development of the space instrument. The international LISA consortium was formally established on 2 March.
The Laser Interferometer Space Antenna (LISA) will be able to do in space what interferometers of the LIGO Virgo Collaboration did on Earth for the first time in history on 14 September 2015: detect gravitational waves. These gravitational waves had a 'short' wavelength. LISA is aimed at waves with a far longer wavelength.
Ripples in space
Gravitational waves are ripples in space, which Einstein had already predicted, caused by extreme events in the universe. These waves can be measured when laser beams span two long ‘measurement arms’. A change in the interference pattern between the laser light waves indicates that the arms must have changed in length, and that could only be the case if spacetime was deformed by a gravitational wave.
"In space, the 'measurement arms' of LISA will be 2 million kilometres long, which will allow gravitational waves of this wavelength to be detected as well," says Gijs Nelemans, project leader for the Dutch contribution to LISA. "LISA will be able to detect elongated ripples that are the consequence of cosmic hammer blows such as merging supermassive black holes, even if these have occurred in the farthest reaches of the universe. But also elongated ripples caused by more modest cosmic collisions closer by, such as binary stars with white dwarfs, neutron stars and black holes in our own Milky Way."
Centre for research into gravitational waves
The Netherlands had already played crucial role in the ground-breaking detection of September 2015 with researchers from Nikhef, the VU University Amsterdam and Radboud University. The Einstein Telescope (ET) for gravitational waves with a short wavelength also might be realised in the Netherlands with the involvement of Nikhef. The same applies for the International Pulsar Timing Array, with the involvement of ASTRON, which will measure waves with an even longer wavelength than LISA.
Jo van den Brand, programme leader of the research into gravitational waves at Nikhef: "In the future, the Netherlands could in many aspects become an attractive centre for research into gravitational waves. Furthermore, we can consolidate our strengths and develop technology that can be used both on Earth and in space."
Dutch institutes previously collaborated on the test mission LISA Pathfinder. With that mission, crucial technology for LISA was tested in space. It is expected that the institutes will be able to contribute to LISA with optical systems, electronics for the 'phase camera', calibration and data processing, and more. Funding still needs to be made available for this, however. The official LISA trailer provides additional information on this topic.
Further information
For further information, please contact
Gijs Nelemans, +31 6 45 12 01 89
Elisa Rossi, +31 6 81 12 14 40 or +31 71 527 58 77
Rens Waters, +31 88 777 58 00 or
Jo van den Brand, +31 20 592 20 15 or +31 6 20 53 94 84.
You can also contact SRON spokesperson Frans Stravers at +31 6 52 67 93 95.