It's the largest black hole merger ever observed by scientists.
- In 2019, scientists detected gravitational waves that were later determined to come from the merging of two so-called "intermediate-mass" black holes.
- These black holes were thought to exist, but had never been directly observed.
- The discovery sheds new light on how black holes form.
Intermediate-mass black holes<p>Scientists know relatively little about these mid-sized black holes. They've catalogued small black holes only a few times more massive than the Sun, as well as supermassive black holes more than six billion times the mass of our star. But direct evidence of intermediate-mass black holes has remained elusive.</p><p style="margin-left: 20px;">"Long have we searched for an intermediate-mass black hole to bridge the gap between stellar-mass and supermassive black holes," Christopher Berry, a professor at Northwestern University's Center for Interdisciplinary Exploration and Research in Astrophysics), <a href="https://news.northwestern.edu/stories/2020/09/scientists-detect-first-of-its-kind-intermediate-mass-black-hole-gravitational-waves/" target="_blank">told</a> Northwestern Now. "Now, we have proof that intermediate-mass black holes do exist."</p><p>Still, how these middleweight black holes form is a mystery. Scientists know that smaller black holes form when stars explode in violent events called supernovas. But mid-sized black holes couldn't form this way, according to current physics, because stars of a certain mass range undergo a death process called pair instability, where they explode and leave nothing behind, not even a black hole.</p>
This chart compares the mass of black-hole merger events observed by LIGO-Virgo.
Visualization of a black hole.
Credit: NASA<p>The recent discovery sheds light on how black holes form, but questions still remain. Scientists with the LIGO-Virgo collaboration hope to continue studying the newly discovered intermediate black hole — dubbed GW190521 — in 2021 when the facilities will be up and running again with improved instruments.</p><p style="margin-left: 20px;">"Our ability to find a black hole a few hundred kilometers-wide from half-way across the Universe is one of the most striking realizations of this discovery," Karan Jani, an astrophysicist with LIGO <a href="https://themalaysianreserve.com/2020/09/04/mysterious-intermediate-mass-black-hole-found/" target="_blank">told</a> The Malaysian Reserve.</p><p>The discovery was described in two papers published in the<a href="https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.125.101102" target="_blank" rel="noopener noreferrer"> Physical Review Letters</a> and <a href="https://iopscience.iop.org/article/10.3847/2041-8213/aba493" target="_blank" rel="noopener noreferrer">The Astrophysical Journal Letters</a>.</p>
Gravitational wave researchers observe black holes of different sizes colliding for the first time.
- Gravitational wave researchers at LIGO and Virgo observatories spot black holes of different sizes colliding.
- The finding is unusual because previous black hole mergers involved partners of similar size.
- The new information re-confirms Einstein's theory of relativity.
Researchers find what causes the glow coming from the densest objects in our universe.
- Columbia University astrophysicists discovered the cause of the unusual glow coming from regions of space with black holes and neutron stars.
- The researchers ran some of the largest computer simulations ever to reach their conclusions.
- They found that turbulence and reconnection of super-strong magnetic fields are responsible for the light.
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A massive super-computer simulation demonstrates the strong particle density fluctuations that happen in the extreme turbulent environments home to black holes and neutron stars. The dark blue regions are low particle density regions, and the yellow regions are over-dense regions. Particles are accelerated to extremely high speeds from interacting with turbulence fluctuations.