By Harvey Sapigao
In 1916, Albert Einstein theorized that two merging black holes create ripples in the spacetime fabric, similar to how a pebble creates ripples in a pond. These ripples, called gravitational waves, stretch and squeeze spacetime in amounts so minuscule that they were once believed to be too faint to detect.
But a century later, the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the US, an L-shaped facility with arms spanning four kilometers each, detected minute discrepancies in how long lasers travel through each arm, signaling the first detection of gravitational waves.
Now, scientists are preparing to launch a more sophisticated observatory into space, aiming to detect even fainter gravitational waves or those beyond LIGO’s capabilities. This space-based facility, known as the Laser Interferometer Space Antenna or LISA, is a triangular observatory with sides spanning tens of millions of kilometers and is set to launch in the 2030s.
As preparation ramps up, scientists around the world are pitching ideas to improve LISA’s detection capabilities. Dr. Reinabelle Reyes and her former graduate student Marco Immanuel Rivera, from the UP Diliman College of Science’s National Institute of Physics (UPD-CS NIP) recently published a study identifying a set of parameters that could improve the analysis of signals coming from LISA and future gravitational-wave observatories.
Unlike LIGO, which mainly detects gravitational waves coming from two stellar-mass black holes, LISA hopes to detect a type of gravitational wave coming from compact objects – such as neutron stars, white dwarfs, and stellar-mass black holes – orbiting supermassive black holes. “When a stellar-mass black hole orbiting a supermassive black hole falls into it, an extreme-mass ratio inspiral (EMRI) gravitational-wave signal is produced,” Dr. Reyes and Rivera explained. #
