black hole collisions to measure how fast universe is expanding
According to data obtained from the Hubble Telescope, the universe is expanding rapidly. Why this is happening is still a matter of mystery. Scientists call the speed of this expansion the Hubble constant.
Astronomers believe that this rate of rapid expansion of the universe is due to the mysterious dark energy that is tearing galaxies apart.
The word 'dark' is used to denote the unknown. Dark energy is a mysterious form of energy that makes up about 68% of the universe. Scientists say that by solving some of the mysteries surrounding dark energy, the mystery of cosmic expansion can be solved.
Now, In a new study published in Physical Review Letters, astrophysicists at the University of Chicago have found a way to use black hole collisions to measure the rate of expansion of the universe, named the 'Spectral siren' method.
Sometimes, when two black holes collide, powerful events like this send ripples of spacetime across the universe. These waves are called gravitational waves.
The new technique measures the changes in these signals that occur when they experience the expansion of the universe.The new study provides a way to do this calculation using special detectors that pick up on cosmic echoes of black hole collisions.
This method can also reveal how the universe evolved, what it is made of, how it looked in its early years, and how and where it is expanding.
A better understanding of the evolution of the universe could help cosmologists solve some major puzzles about dark energy.Scientists also want to determine when this mysterious force dark energy began to rule matter and why this switch occurred.
Over the years, LIGO and its companion instruments have collected readings from about 100 pairs of colliding black holes.
Each collision signal also contains information about how massive the black holes are.But the signal has been moving in space, and during that time the universe has expanded, which changes the properties of the signal.
"For example, if you take a black hole and put it earlier in the universe, the signal will change and it will look like a bigger black hole than it actually is."said research co-author and University of Chicago astrophysicist Daniel Holz.