The merger of two black holes, such as the one which produced the gravitational waves discovered by the LIGO Observatory, is considered an extremely complex process that can only be simulated by the world's most powerful supercomputers. However, two theoretical physicists from the University of Barcelona (Spain) have demonstrated that what occurs on the space-time boundary of the two merging objects can be explained using simple equations, at least when a giant black hole collides with a tiny black hole.
If we had to choose the most important and newsworthy piece of science news for 2016, the discovery of gravitational waves would have every chance of winning first prize.
The merger of two black holes, where one is so large that only a portion of it –nearly flat– is shown, while the other, smaller black hole falls into and is absorbed by the larger one. / Credit: Roberto Emparan & Marina Martínez
The two signals that have been produced so far came from the collision and merger of two black holes in some remote part of the universe. The first detection was announced in February and the second in June, both by scientists from the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the United States.
To determine the patterns of these waves and simulate how those mysterious fusions take place -a phenomenon characteristic of Einstein's general theory of relativity- scientists use the best supercomputers, such as the MareNostrum from Barcelona, Spain's most powerful supercomputer; however, there could be other, less complicated ways.
Physicists Roberto Emparan and Marina Martínez from the University of Barcelona have found a simple and exact way to approach the subject of the event horizon of two merging black holes, where one is much smaller than the other.
The joining together of horizons
The event horizon is the boundary that characterises a black hole; whereas the events inside the event horizon cannot affect an observer on the outside, the opposite can occur. When two black holes merge together, their event horizons join together to become one.
"Surprisingly, the ideas and techniques used in our work are elemental and allow us to thoroughly study the properties of the horizon at the moment both black holes join together to form one", points out Emparan, who along with his colleague has published the results in the journal 'Classical and Quantum Gravity'.
The equations utilised to solve the problem are based on the physicists' basic knowledge, such as the definition of an event horizon and the so-called equivalence principle, which is part of the foundation of Einstein's theory of gravity.
According to this idea, an observer cannot tell the difference between free falling in a gravitational field and floating in deep space.
This is something we are familiar with because of pictures of astronauts on the International Space Station. Their noticeable weightlessness is not a result of their distance from Earth -gravity at the altitude of the station is 90% that of the gravity on Earth's surface- but is rather due to the fact that the orbiting station and the astronauts inside are freely moving through Earth's gravitational field.
A universal behaviour of two black holes that make contact
Likewise, in this study the small black hole that falls into a much larger one cannot tell this fall apart from another situation in which it is floating alone in space, thus allowing the description of the phenomenon to be greatly simplified.
Emparan and Martínez have utilised geometric elements in their study in order to describe the event horizon. Specifically, the horizon is obtained by plotting null geodesic lines on the so-called Schwarzschild metric, the solution to the field equations posed by Einstein for describing the gravitation field of a black hole.
According to the authors, these results make it easy to identify many geometric properties of the event horizon at the moment the two black holes join together. More importantly, "[the results] indicate the existence of a universal, general behaviour that occurs when two black holes come into contact with each other in any part of the universe".
For further information, please contact:
Notes for editors
Para contactar con los investigadores:
Roberto Emparan and Marina Martínez. Universidad de Barcelona
Emails: firstname.lastname@example.org y email@example.com
Tlf.: +34 934034818
Enrique Sacristán López
Redactor Agencia SINC
Fundación Española para la Ciencia y la Tecnología
Edificio Museo Nacional de Ciencia y Tecnología
C/ Pintor Velázquez, 5 - 28100 Alcobendas (Madrid)
Tfno: 91 425 09 09 ext. 3251 - Fax: 91 571 21 72
Enrique Sacristan | AlphaGalileo
Structured light and nanomaterials open new ways to tailor light at the nanoscale
23.04.2018 | Academy of Finland
On the shape of the 'petal' for the dissipation curve
23.04.2018 | Lobachevsky University
At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.
Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...
Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.
Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
24.04.2018 | Information Technology
24.04.2018 | Earth Sciences
24.04.2018 | Life Sciences