The exploration of the universe is approaching an important new milestone. Gravitational waves, those tiny oscillations of spacetime that Albert Einstein predicted in 1916 and have directly detected on Earth since September 2015, will soon be observed from space. An ambitious project that promises to revolutionize our understanding of the universe.
An international team of scientists, including an astrophysicist from Northwestern University, has received approval to build a new detector, this time in orbit around Earth.
On January 25, the European Space Agency (ESA) officially adopted the Laser Interferometric Space Antenna (LISA) project and plans to build and launch it within a decade.
LISA's discoveries will enrich our knowledge of the origin, evolution and structure of the universe. The detector will respond to gravitational waves of lower frequency than those detected by terrestrial observatories such as the Laser Interferometry Gravitational Wave Observatory (LIGO).
A giant leap for astrophysics
“This is an important milestone for LISA,” said Shane Larson, American member of the LISA consortium and co-chair of the consortium’s Astrophysics Working Group.
“The mission has been designed and planned, and new technologies have been built and tested. Today it is official that we start construction and commissioning. It will be the first gravitational wave observatory in space. It will likely be the only one of its kind for decades, changing the landscape of astronomy. »
Larson is a research professor of physics and astronomy and associate director of the Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) at Northwestern University. He is interested in how gravitational waves can be used to understand aspects of the universe that light cannot reveal.
Larson's research group at Northwestern University simulates the population of dead binary star systems, called white dwarfs, in the Milky Way, which will be one of the main sources of observations for LISA.
A new window to the universe
Gravitational waves are caused by the rapid movement of compact massive objects such as neutron stars and black holes. LISA will be particularly sensitive to large-scale events such as collisions of massive black holes at the centers of galaxies and smaller binary systems of dead stars consisting of white dwarfs, neutron stars or black holes.
LISA will detect gravitational radiation in the still unexplored range between 0.1 MHz and 1 Hz, waves that cannot be detected by ground-based detectors. LISA will be unique in detecting gravitational waves from stellar black holes swirling around massive black holes in galactic cores.
The LISA instrument will consist of three triangular spacecraft with 2.5 million kilometer long arms moving in an Earth-like orbit around the sun. Gravitational waves from sources throughout the universe produce slight vibrations at arm's lengths (smaller than the diameter of an atom).
LISA will detect these movements and use laser links to measure gravitational waves to monitor the movements of free-falling test masses inside spacecraft.
Caption: The planned LISA mission will detect gravitational waves in space using a trio of satellites millions of kilometers apart. Lasers are used to measure tiny changes in their relative distance caused by the influence of gravitational waves. Image by AEI/MM/exozet; Simulation of gravitational waves: NASA/C. Henze
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