by Humanity’s first space-based gravity detector has been given the go-ahead.
The Laser Interferometer Space Antennas (LISA) mission is a collaboration between NASA and the European Space Agency (ESA), consisting of three spacecraft that combine to form a single gravitational detector. It is due to launch in the mid-2030s.
The GSE announced the acceptance of LISA on January 25, and recognizes that sufficient progress has been made on the mission concept and related technology. It can get the green light that scientists can start building the spacecraft as well as the required instruments; work will begin in January 2025 after a European industrial contractor has been selected for construction.
Liza’s three spacecraft will track Earth and our planet in orbit around the sun, forming an equilateral triangle in space. Each side of this triangle will be 1.6 million miles (2.6 kilometers) long. LISA’s craft will fire laser beams down these sides, which will undergo minute changes as gravitational waves pass over them, pushing and shoving the fabric of space.
“LISA is an effort that has never been attempted before,” LISA lead project scientist Nora Lützgendorf said in a statement. “Using laser beams over distances of several kilometers, ground-based instrumentation can detect gravitational waves originating from events involving stellar objects — such as supernova explosions or the merger of hypernova stars and stellar-mass black holes. To expand the limit. of gravitational studies, we must go to space.”
Related: The universe is humming with gravitational waves. This is why scientists are so excited about the discovery
Gravitational waves were first predicted by Albert Einstein, arising from his 1915 theory of gravity: General relativity.
This revolutionary theory suggested that gravity arises as a result of objects with mass encircling the fabric of space and time, which is unified as a single entity called space-time. The greater the mass of an object, the greater the curvature created by the object – and therefore the greater its gravitational influence. So general relativity explains, for example, why stars have stronger gravity than planets, but black holes have stronger gravity than stars.
Furthermore, general relativity states that when a body accelerates in space, this motion creates ripples in spacetime that radiate outward. These gravitational waves are insignificant unless the accelerating objects are massive, dense objects (such as black holes or neutron stars) orbiting each other and eventually colliding. Collapsing massive stars, which also trigger supernova explosions, can send out some substantial waves.
However, even in the most extreme cases, Einstein believed that gravitational waves would still be too small to be detected from Earth. He was wrong about that.
Fortunately, in September 2015, the Laser Gravitational-Wave Observatory (LIGO) in the United States and the Virgo interferometer in Italy have indeed discovered holes in space-time. These waves were created by the collision and merger of two black holes 29 and 36 times the mass of the sun, located more than 1 billion light years away.
And. since then, gravitational astronomers have detected signals from many events, including more black hole mergers, neutron star collisions and even mixed black hole–neutron star mergers.
LISA is poised to take this achievement even further as a space-based interferometer with the sensitivity to “hear” gravitational waves from merging black holes, neutron stars and supernovae at far greater distances than Earth-based detectors can. -based. This also means that it will be able to search for waves originating from events further back in time.
“Thanks to the great distance traveled by the laser signals on LISA and the excellent stability of its instrumentation, we will examine gravitational waves at lower frequencies than possible on Earth, revealing events on a different scale, all the way back to the beginning of the day. time,” said Lützgendorf.
As well as detecting gravitational waves from more distant sources, LISA should provide astronomers with the sensitivity to investigate closer and less extreme events, such as the merger of compact white stars, which are born when small stars like the sun die.
Related Stories:
— ‘ring’ of black holes colliding across space-time with gravitational wave vibrations
— Colliding black holes could hide in the light of extremely bright quasars
— 2 merging supermassive black holes visible at ‘cosmic noon’ early in the universe
“For centuries, we have been studying our cosmos by capturing light. And combining this with the detection of gravitational waves gives a completely new dimension to our perception of the Universe,” said the project scientist Liza, Oliver Jennrich, in the statement. “If we imagine that, until now, with our astrophysics missions, we are watching the cosmos like a silent film, to capture the ripples of the space-time with Liza being a real game-changer, as when sound was added to motion pictures.”
