Researchers at the Monash Centre for Astrophysics, looking at gravitational waves, have just discovered a thing called "Orphan Memory".
Here's what the deal is and why it's so cool.
For the first time in history, astronomers have observed elusive gravitational waves — ripples in space time caused by a violent cosmic event taking place in the distant Universe. Scientists from Australian universities and CSIRO are celebrating their part in the discovery of the waves, which were predicted by Albert Einstein 100 years ago.
The whole idea of "Orphan Memory" changes the current thinking around gravitational waves. So basically: Einstein's theory of general relativity predicts that cataclysmic cosmic explosions stretch the fabric of spacetime (yes, really).
The stretching of spacetime is called "gravitational waves." But after such an event, spacetime does not return to its original state. It stays stretched out. This effect is called "memory." The term "orphan" alludes to the fact that the parent wave is not directly detectable.
So, well, I'll let the researchers explain:
"These waves could open the way for studying physics currently inaccessible to our technology," says Monash School of Physics and Astronomy Lecturer, Dr Eric Thrane. "This effect, called 'memory' has yet to be observed."
Gravitational-wave detectors (such as LIGO) only "hear" gravitational waves at certain frequencies, says lead researcher Lucy McNeill.
"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,” she said. "But this study shows LIGO can be used to probe the universe for gravitational waves that were once thought to be invisible to it."
Study co-resaearcher Dr Lasky said LIGO won't be able to see the oscillatory stretching and contracting, but it will be able to detect the memory signature if such objects exist. The team was able to show that high-frequency gravitational waves leave behind a memory that LIGO can detect.
"This realisation means that LIGO may be able to detect sources of gravitational waves that no one thought it could," said Dr Lasky.
You can read the full research here.