May 23 (UPI) -- New research suggests LIGO and similar gravitational wave detectors can "hear" gravitational waves that scientists previously believed were invisible.
Astrophysicists believe LIGO, the Laser Interferometer Gravitational-Wave Observatory, could detect high-frequency gravitational waves by measuring a phenomenon called "orphan memory."
Gravitational waves are ripples in spacetime caused by ultra-powerful cosmic explosions. These waves bend and stretch spacetime. Once passed, spacetime does not revert to its original form. The wave's signature remains as a "memory." The modifier "orphan" refers to the fact that the parent signal, or parent wave, is unknown.
"These waves could open the way for studying physics currently inaccessible to our technology," Eric Thrane, a professor of physics and astronomy at Monash University in Melbourne, Australia, said in a news release.
Though orphan memory has yet to be observed, researchers suggest it could be -- and that it could be used to study gravitational waves previously believed to be undetectable. Scientists detailed their claims in the journal Physical Review Letters.
"If there are exotic sources of gravitational waves out there, for example, from micro black holes, LIGO would not hear them because they are too high-frequency," said lead researcher Lucy McNeill. "But this study shows LIGO can be used to probe the universe for gravitational waves that were once thought to be invisible to it."
Though LIGO won't be able to measure the stretching and contraction of the parent wave, it will be able to detect the wave's memory, allowing researchers to confirm exotic gravitational wave sources.
"This realization means that LIGO may be able to detect sources of gravitational waves that no one thought it could," said physicist Paul Lasky.