New research suggests that "exotic compact objects" could soon destroy physics.

In the depths of the universe, extravagant entities, similar to black holes could exist with the power to redefine physics as we know it. A new study calculates that, in the coming years, gravity wave observatories on Earth might find these hypothetical eccentrics, which are known as exotic compact objects.

The U.S.-based Laser Interferometer Gravitational-Wave Observatory (LIGO) and its European counterpart Virgo were built to capture ripples in the fabric of space-time radiating from massive objects like black holes and neutron stars crashing together. However, there is always the possibility that scientists will come up against something unexpected.

"We can't be so naïve to presume that we know everything that is out there," Luís Longo, a doctoral candidate in physics at the Universidade Federal do ABC in São Paulo, Brazil, told Live Science.

The researchers speculated on the possibilities of exotic compact objects for many years, and tried to figure out what they would look like a gravitational wave sensor, Longo added.

The term "exotic compact object" includes a number of theoretical entities. Among the possibilities are gravastars, which would appear quite similar to an ordinary black hole but would be filled with dark energy, a mysterious substance causing the accelerated expansion of the universe. Another compact object that could lurk in the universe is a fuzzball, a black-hole-like knot of fundamental one-dimensional strings proposed in string theory, which attempts to unify and replace the currently accepted theories in physics.

The thing that links exotic compact objects is that, unlike a black hole, they should lack an area known as the event horizon, Longo says. According to Albert Einstein's theory of relativity, the event horizon is a sphere around a black hole beyond which all travel becomes unidirectional. Objects can slide inside the event horizon, but nothing can come out of them—not even light.

But scientists know that Einstein's theory of relativity will eventually have to be superseded. Although the theory is extraordinarily effective in describing gravity and massive cosmic entities, it does not speak to the behavior of subatomic particles. To do this, physicists rely on quantum mechanics.

The hope is that someday a theory of quantum gravity will prevail over relativity and quantum mechanics. Exotic compact objects, which would be like a black hole but have no event horizon, could help provide the information necessary to start building this future theory.

"They will break with general relativity because they will not give rise to any of her key predictions," Longo said, referring to the horizon of the event. "In that sense, we would test the theory of gravitation of Einstein."

As two black holes crash and merge, they turn around each other, deforming space-time and sending gravitational waves, which can sound LIGO detectors on Earth. After their encounter, the horizon of the event prevents additional waves from escaping outwards, Longo said.

But because exotic compact objects would lack an event horizon, some gravitational waves could fall inward towards the object's center and then bounce back, creating gravitational echoes that leak outward, he added. These echoes are too faint for LIGO and Virgo to detect right now, but the facilities are currently being upgraded for increased sensitivity, and they’ve been joined by the Kamioka Gravitational Wave Detector (KAGRA) in Japan, which became operational last year.

Longo and his colleagues have calculated that during the gravitational wave detectors' next observation run, set to begin in the summer of 2022, LIGO and its counterparts could be sensitive enough to pick up the signal from one or two exotic compact objects, if they exist. Longo will present his team's results during the April meeting of the American Physical Society on April 19.

Other researchers are interested in considering whether such a scenario could occur in the near future. 'Right now it looks like science fiction,' said Vitor Cardoso, a physicist at the Instituto Superior Técnico in Lisbon, Portugal, to Live Science. 'But it is rapidly shifting from science fiction to mainstream science.'

Cardoso would be delighted if exotic compact objects were revealed to be more than speculation. "We hate to see what we await," Cardoso said. "We can't stand boring science."

However, even if LIGO detected echoes, it would probably still take a long time for the scientific community to confirm that they were really pointing to these hypothetical quirks, he added.

Longo would also be pleased if the observatories could find evidence of exotic compact objects. "That would be the first indication of the rupture of general relativity," he said. "It would be a huge and tremendously exciting breakthrough."

Originally published on Live Science.