Title LISA Pathfinder in space
Released 25/11/2015 3:00 pm
Artist’s impression of LISA Pathfinder, ESA’s mission to test technology for future gravitational-wave observatories in space.
LISA Pathfinder will operate from a vantage point in space about 1.5 million km from Earth towards the Sun, orbiting the first Sun–Earth Lagrangian point, L1.
Animated sequence of the journey: LISA Pathfinder’s journey to L1
11 February 2016
ESA is thrilled to learn that gravitational waves have been detected, and is looking forward to starting its mission to test technologies that could extend the study of these exotic waves to space.
Gravitational waves are elusive no more: an exciting breakthrough that has been 100 years in the making.
In November 1915, Albert Einstein presented his general theory of relativity, introducing a dramatic change of perspective in the physical understanding of one of the four fundamental interactions of nature: gravity.
This theory describes gravity as the way matter interacts with the flexible ‘spacetime’ it is embedded in. Massive bodies deform spacetime, changing its curvature as they move.
When accelerated, massive bodies produce tiny fluctuations in the fabric of spacetime – gravitational waves – which were first predicted in a further study published by Einstein in 1918. These minuscule cosmic perturbations have finally been revealed, after almost a century of theoretical investigations and experimental searches.
The discovery was announced today by scientists from the Laser Interferometer Gravitational-Wave Observatory (LIGO) collaboration.
LIGO comprises two gravitational wave detectors in Livingston, Louisiana and Hanford, Washington, USA, and involves over a thousand scientists from across the world. The experiment uses laser beams to monitor two perpendicular arms, each extending 4 km, to look for tiny changes in their length that might be caused by passing gravitational waves.
Recently upgraded to become Advanced LIGO, the experiment obtained this historic result during the first observation run in the new configuration, which collected data between September 2015 and January 2016.
“This is tremendous news for everyone studying gravity and general relativity, and we send our warmest congratulations to colleagues in the LIGO collaboration for their outstanding result,” says Paul McNamara, LISA Pathfinder project scientist at ESA.
LISA Pathfinder is ESA’s technology demonstration mission for possible future missions to observe gravitational waves from space. Launched on 3 December 2015, the spacecraft reached its operational orbit in January and is undergoing final checks before starting its science mission on 1 March.
“With LISA Pathfinder, we will be testing the underlying technology to observe gravitational waves from space, and it is even more encouraging to know that these long-mysterious fluctuations have now been directly detected,” adds Paul.