On Thursday, the European Space Agency’s Scientific Program Committee gave the green light laser interferometer space antenna, or LISA project. This means construction of the mission’s three spacecraft could begin as early as a year later. The interferometer follows the same basic principles as his ground-based LIGO (Laser Interferometer Gravitational-Wave Observatory) experiment that first detected gravitational waves, but the hardware is located 2.5 million kilometers away and is completely new. You will be able to sense the astronomical range. phenomenon.
Proven technology
Existing gravitational wave detectors rely on shuttling lasers between distant mirrors before recombining them to create an interference pattern. Anything that changes the mirror’s position, from the roar of a large truck to the passing of gravitational waves, changes the interference pattern. Placing the detector in a remote location eliminates cases of local noise and allows for the detection of astronomical phenomena.
Detectors we have built on Earth have successfully captured gravitational waves produced by the merger of compact objects such as neutron stars and black holes. But its relatively compact size means it can only capture high-frequency gravitational waves, which are generated only in the last few seconds before the merger occurs.
To capture details of the process, we need to detect low-frequency gravitational waves. And that means the distance between the interferometer’s mirrors is much greater, shielding it from Earth’s seismic noise. It means going to space.
LISA’s design consists of a spacecraft shell that absorbs the dust and cosmic ray bombardment that penetrates the solar system and outputs a laser powerful enough to reach 2.5 million kilometers. It also houses a telescope for focusing the incoming laser light, spreading it out over these distances from its usual narrow beam. The free-floating mass inside it is isolated from the rest of the universe and should provide a stable platform for the laser to capture any changes in the universe. Three spacecraft track Earth in orbit around the sun, each sending lasers to the other two in a triangular configuration.
It may sound like science fiction, but ESA has already sent the Pathfinder mission into space to test this technology.and it was executed 20x better than planned, providing the three times the sensitivity required for LISA to work. Therefore, there are no obvious problems.
Towards super-huge size
Once in space, it should immediately detect the impending collision that led to LIGO’s detection. But it allows you to discover them a whole year or so in advance and track where the event horizon touches. This allows us to track the physics of their interactions over time, orient optical telescopes in the right direction prior to a collision, and determine whether any of these events produce radiation. It will look like this. (This might allow us to assign a cause to some classes of events that we have already detected via photons.)
But that’s only part of the benefit. Because of their much larger size, supermassive black hole mergers are only detectable at lower frequencies. These are expected to occur after the merger of many galaxies, so there is hope that we will be able to capture them.
Perhaps the most exciting prospect is that LISA can detect early gravitational fluctuations that formed shortly after the Big Bang. It has the potential to provide a new view into the earliest history of the universe, completely independent of the cosmic microwave background.
As excited as I am, I regret to inform you that the release date is not scheduled until 2034. So, good luck for the next 10 years. I promise it’s worth it.