Gravitational waves are huge ripples in space-time's fabric. (Image credit: Shutterstock)
Two unusual signals were detected in a small gravitational wave detector. They could be signs of all sorts, from new physics to dark-matter interaction with black holes to vibrations at the very beginning of the universe. Researchers are cautious about making any claims due to the novelty of this experiment.
Laser Interferometer Gravitational-Wave Observatory, (LIGO), uses huge laser-driven detectors to search for gravitational waves in space-time. These are caused by the collisions between black holes and neutron star out in the distant universe. These events are so powerful that they shake space-time and emit waves with wavelengths measuring in hundreds of miles.
Related: 8 ways that we know black holes exist
Scientists knew long before the construction of these massive observatories that gravitational waves of this size existed because they knew that neutron stars and black holes could sometimes collide together. Michael Tobar, a University of Western Australia physicist, shared his suspicions with Live Science.
He said that there are no well-understood sources of gravitational waves with shorter wavelengths, such as those between a few feet or a few miles. Tobar stated that there are always unexpected things in the universe.
Tobar and his coworkers have been working hard to develop detectors that can detect these smaller gravitational wave sizes in recent years. The device is made of crystal quartz and measures 1 inch (3 cm) in diameter. It has a resonant chamber which produces an electrical signal when it vibrates at specific frequencies.
This image shows the crystal heart of the gravitational-wave detector. It is a simple resonator with no electrodes. (Image credit: Michael Tobar)
Tobar compared the setup to a bell, or a gong, that rings at a specific pitch. He said, "If a gravitational waves hit that it would excite it." Electrical sensors pick up the electromagnetic signal from the crystal's ringing.
To minimize thermal vibrations, the researchers placed the detector behind radiation shields.
The experiment lasted 153 days. The crystal rang twice during the 153-day period. Each time, it rang for one to two seconds. The team's findings were published in Physical Review Letters on Aug. 12.
Scientists are trying to figure out why these results occur. Tobar suggested that cosmic rays, charged particles known as cosmic rays, could be one explanation. Tobar said that another type of thermal fluctuation, previously unknown, in the crystal due to super-cold temperatures could be another explanation.
Researchers wrote that there are many other possibilities, including a type dark matter called an axion spinning around black holes and emitting gravitational waves. Tobar stated that many explanations may require new physics beyond what is described in the Standard Model, which describes nearly all subatomic particles and forces within the universe.
Cosmologists believe that the universe experienced an inflation period shortly after the Big Bang. This was a period during which the universe grew exponentially in size. Francesco Muia, a theoretical scientist at the University of Cambridge, U.K., said Live Science.
He suggested that the universe may have experienced a phase change at the end of the era. This is similar to water changing from liquid to gas when it boils. Muia suggested that this transition could have resulted in large amounts of energy being deposited into space-time. This would have generated gravitational waves, which could be observed by this experiment.
Although he doesn't believe there is enough evidence to determine the exact nature of the events in crystal, he is eager for this experiment and other similar ones to be made available online in the near future.
Tobar agreed. Tobar agreed.
He said that now that they have made these discoveries, they will be able to build more sensors. Multiple devices can see the same signal simultaneously, which could point to an outside phenomenon and rule out internal processes such as thermal fluctuations within the crystal.
Original publication on Live Science
