Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How to merge two black holes in a simple way

26.09.2016

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 complete sequence

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".

  • Full bibliographic informationRoberto Emparan, Marina Martínez. "Exact Event Horizon of a Black Hole Merger". Classical and Quantum Gravity 33. Number 15, 2016. DOI: 10.1088/0264-9381/33/15/155003

For further information, please contact:

Enrique Sacristan

enrique.sacristan@fecyt.es

Notes for editors

Para contactar con los investigadores:
Roberto Emparan and Marina Martínez. Universidad de Barcelona
Emails: emparan@ub.edu y marinamartinez@ub.edu
Tlf.: +34 934034818

Enrique Sacristán López
Redactor Agencia SINC
www.agenciasinc.es
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

More articles from Physics and Astronomy:

nachricht What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin

nachricht Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Metal too 'gummy' to cut? Draw on it with a Sharpie or glue stick, science says

19.07.2018 | Materials Sciences

NSF-supported researchers to present new results on hurricanes and other extreme events

19.07.2018 | Earth Sciences

Scientists uncover the role of a protein in production & survival of myelin-forming cells

19.07.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>