Et kunstnerinntrykk av to kolliderende sorte hull. Forskere har identifisert en særegen vridningsbevegelse i banene til to kolliderende sorte hull, et eksotisk fenomen spådd av Einsteins tyngdekraftsteori.
Gravitasjonsbølger identifiserer det som kan være en sjelden én-i-1000-hendelse.
Astronomer ved Cardiff University har identifisert en merkelig vridningsbevegelse i banene til to kolliderende sorte hull. Dette eksotiske fenomenet er spådd av Einsteins teori om tyngdekraften.
Studien deres rapporterer at dette er første gang denne effekten, kjent som presesjon, er sett i sorte hull, der vridningen er 10 milliarder ganger raskere enn i tidligere observasjoner. Under ledelse av professor Mark Hannam, Dr. Charlie Hoy og Dr. Jonathan Thompson ble forskningen publisert 12. oktober i tidsskriftet Natur.
Den avanserte[{” attribute=””>LIGO and Virgo detectors found the binary gravitational waves. Additionally, in contrast to all previous observations, the rapidly revolving black hole distorted space and time so much that the binary’s entire orbit wobbled back and forth.
This form of precession is specific to Einstein’s theory of general relativity. These results confirm its existence in the most extreme physical event we can observe, the collision of two black holes.
“We’ve always thought that binary black holes can do this,” said Professor Mark Hannam of Cardiff University’s Gravity Exploration Institute. “We have been hoping to spot an example ever since the first gravitational wave detections. We had to wait for five years and over 80 separate detections, but finally we have one!”
A more down-to-earth example of precession is the wobbling of a spinning top, which may wobble – or precess – once every few seconds. By contrast, precession in general relativity is usually such a weak effect that it is imperceptible. In the fastest example previously measured from orbiting neutron stars called binary pulsars, it took over 75 years for the orbit to precess. The black-hole binary in this study, colloquially known as GW200129 (named after the date it was observed, January 29, 2020), precesses several times every second – an effect 10 billion times stronger than measured previously.
Dr. Jonathan Thompson, also of Cardiff University, explained: “It’s a very tricky effect to identify. Gravitational waves are extremely weak and to detect them requires the most sensitive measurement apparatus in history. The precession is an even weaker effect buried inside the already weak signal, so we had to do a careful analysis to uncover it.”
Gravitational waves were predicted by Einstein in 1916. They were first directly detected from the merger of two black holes by the Advanced LIGO instruments in 2015, a breakthrough discovery that led to the 2017 Nobel Prize. Gravitational wave astronomy is now one of the most vibrant fields of science, with a network of the Advanced LIGO, Virgo, and KAGRA detectors operating in the US, Europe, and Japan. To date, there have been over 80 detections. All of them have been merging black holes or neutron stars.
“So far most black holes we’ve found with gravitational waves have been spinning fairly slowly,” said Dr. Charlie Hoy, a researcher at Cardiff University during this study, and now at the DOI: 10.1038/s41586-022-05212-z
The authors were supported by funding from the Science and Technology Facilities Council (STFC) and European Research Council (ERC).