Black Hole Collisions Could Help us Measure how Fast the Universe is Expanding

Black Hole are often where data disappears, but researchers may have discovered a way to harness their final moments to reveal knowledge about the origins of the universe. Two University of Chicago astrophysicists have developed a technique for measuring the rate of our universe’s expansion in order to learn more about how the universe evolved, what it is comprised of, and where it is going. Their work was recently published in Physical Review Letters.

The new method, which the researchers refer to as a “spectral siren,” is particularly thought to have the potential to shed light on the previously mysterious “teenage” years of the universe. The Hubble constant, a measurement of how quickly the cosmos is expanding, is a topic of intense scientific discussion. Scientists are eager to discover alternative approaches to measuring this rate because the several methods that are currently available give somewhat varying results.

Because it has an impact on our comprehension of major concepts like the age, history, and make-up of the universe, verifying the accuracy of this number is very crucial. Utilizing specialised detectors that detect the cosmic afterechoes of Black Hole collisions, the new study provides a method for performing this calculation. Rarely, two will collide, a collision so intense that it literally causes a ripple in space-time that spans the entire universe. These ripples, which are known as gravitational waves, can be detected here on Earth by the Italian observatory Virgo and the American Laser Interferometer Gravitational-Wave Observatory (LIGO).

Nearly 100 pairs of colliding Black Hole have been studied by LIGO and Virgo during the last few years. How big the Black Hole were can be determined from the signal of each encounter. However, while the signal has been travelling over space, the cosmos has expanded, changing the signal’s physical characteristics. One of the two authors on the article, UChicago astrophysicist Daniel Holz, said that if a Black Hole were moved earlier in the universe, the signal would shift and it would appear to be larger than it actually is.