University of Chicago How the scientist lays out LIGO Gravitational waves Can be scratched, yielding information.
Is a little far from the principle of our universe. Almost everything fits, but the cosmic ointment has a fly, the infinite sandwich has a grain of sand. Some scientists believe that the culprit may be gravity – and that it may help us to find the missing part from the microscopic ripples in the space-time fabric.
A new paper co-authored by a University of Chicago scientist demonstrates how this works. Published in Physical Review D, December 21, the method is based on finding such ripples that are orbited by traveling through supermassive black holes or large galaxies on Earth’s path.
The problem is that something is expanding the universe, but expanding faster and faster over time – and no one knows what it is. (The discovery of a fixed rate is an ongoing discussion in cosmology).
Scientists have proposed all sorts of theories as to what the missing part might be. Many of these largely depend on changing the way gravity, said Jose Maria Ezquaga, co-author of the paper. NASA Einstein Postdoctoral Fellow at the Cowley Institute for Cosmological Physics in USCago. “So gravitational waves are the perfect messenger to see if these potential changes in gravity exist.”
“Gravitational waves are the perfect messenger to see these potential changes in gravity if they exist.”
– Astrophysicist Jose Maria Izquiga
Gravitational waves are the ripples of space-time itself; Since 2015, humanity has been able to select these ripples using LIGO Observatories. Whenever two massive objects collide somewhere else in the universe, they form a ripple that travels through space, with the signature that it creates – perhaps two black holes or two neutron stars colliding.
Super computer simulation of merging black holes sent by gravitational waves. Scientists believe that there may be a way to use these waves to find the missing pieces in our understanding of the universe. Credit: Illustrated by Chris Heinze / NASA
In the paper, Izquiaga and co-author Miguel Zumal ારે Karegui argue that if such waves hit the supermassive Black hole Or a cluster of galaxies moving to Earth, the signature of the wave will change. If there was a difference in gravity compared to Einstein’s theory, the evidence would be embedded in that signature.
For example, one theory for the missing part of the universe is the existence of an extra particle. Such particles will, among other effects, produce a kind of background or “medium” around large surrounding objects. If a traveling gravitational wave hits a supermassive black hole, it produces waves that merge with the gravitational wave. Depending on what is encountered, the signature of the gravitational wave can carry an “echo” or show a scramble.
“This is a new way to test scenarios that can’t be tested before,” Izquaga said.
A picture of a combination of waves and creating a different new signature. Credit: Izquiaga and Zumalkareregui
Their paper outlines the terms of how such effects can be detected in future data. The next LIGO run is set to begin in 2022, with an upgrade to make detectors already more sensitive.
“During our last observation with Ligo, we saw a new gravitational wave reading every six days, which is amazing. But across the universe, we think they’re actually happening once every five minutes, “said Izquiga. “In the next upgrade, we can see many of them – hundreds of events each year.”
He said the increased number would make it more likely that one or more waves would have passed through a larger object, and that scientists would be able to analyze it for signs of missing components.
Reference: 21 December 2020, “Gravitational Wave Lensing Beyond Normal Relativity: Birefringence, Echoes and Shadows” Physical Review d.
DOI: 10.1103 / Fizervide.102.124048
Zumalkareregui, another author on paper, is a scientist at the Max Planck Institute for Gravitational Physics in Germany, as well as the Berkeley Center for Cosmological Physics at the Lawrence Berkeley National Laboratory. University of California, Berkeley.
Funding: NASA, Kavali Foundation.
