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Prof. Dr. Alessandra Buonanno
Phone:+49 331 567-7220Fax:+49 331 567-7298
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Prof. Dr. Karsten Danzmann
Phone:+49 511 762-2356Fax:+49 511 762-5861
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Dr. Elke Müller
Press & public outreach officer
Phone:+49 331 567-7303Fax:+49 331 567-7298
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Dr. Benjamin Knispel
Press & public outreach officer
Phone:+49 511 762-19104

Simulation

Cosmic collision

The visualization shows the two 29 and 36 solar masses heavy black holes initially from a distance of about 30,000 kilometers. The emitted gravitational waves (orange) can be recognised; the strong gravitational field around the black holes is shown, which can be seen more accurately in the zoom. The strength of the gravitational field decreases from the inside (green) towards the outside (red). When zooming out, the gravitational waves are visible again. The pale orange structures which now appear are particularly strong gravitational waves, which are emitted along the rotational axis (perpendicular to the orbit). Ultimately, the black holes merge. In the final zoom, we see the resulting black hole - it has 62 solar masses - and the strong gravitational field (no waves).

Film

The cosmos quakes

Albert Einstein predicted their existence in the last century, but thought it would be impossible to discover them.

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The discovery of gravitational waves on 14 September 2015 was the crowning moment of a search which had lasted decades and employed ingenious methods. The Max Planck Institute for Gravitational Physics, with its branches in Potsdam-Golm and Hanover, played a crucial role in this success. We discussed this work and the importance and consequences of the discovery with Directors Bruce Allen, Alessandra Buonanno and Karsten Danzmann.

“The signal caught our eye immediately”

The discovery of gravitational waves on 14 September 2015 was the crowning moment of a search which had lasted decades and employed ingenious methods. The Max Planck Institute for Gravitational Physics, with its branches in Potsdam-Golm and Hanover, played a crucial role in this success. We discussed this work and the importance and consequences of the discovery with Directors Bruce Allen, Alessandra Buonanno and Karsten Danzmann.

[more]
September 14, 2015 will go down in history as the day researchers first detected gravitational waves. They pulled off this sensation with the Advanced LIGO installation, whose sensitivity to the gentle trembling from space is based substantially on technologies and methods thought up by scientists at the Max Planck Institute for Gravitational Physics in Hanover and Golm.

The cosmos quakes

September 14, 2015 will go down in history as the day researchers first detected gravitational waves. They pulled off this sensation with the Advanced LIGO installation, whose sensitivity to the gentle trembling from space is based substantially on technologies and methods thought up by scientists at the Max Planck Institute for Gravitational Physics in Hanover and Golm. [more]
Gravitational waves are some of the most spectacular predictions of the 1915 General Theory of Relativity. But fifty years were to pass before physicist Joseph Weber attempted to track them down. At the beginning of the 1970s, Max Planck scientists also began working in this research field and developed second-generation detectors. The groundwork laid by these pioneers meant the waves in space-time ceased to be just figments of the imagination: they were finally ensnared in September 2015.

Tracking down the gentle tremble

Gravitational waves are some of the most spectacular predictions of the 1915 General Theory of Relativity. But fifty years were to pass before physicist Joseph Weber attempted to track them down. At the beginning of the 1970s, Max Planck scientists also began working in this research field and developed second-generation detectors. The groundwork laid by these pioneers meant the waves in space-time ceased to be just figments of the imagination: they were finally ensnared in September 2015. [more]
After decades of intensive preparations, the researchers achieved their goal; on 14 September 2015 two detectors known as Advanced LIGO finally managed to ensnare gravitational waves. 

On the trail of gravitational waves

After decades of intensive preparations, the researchers achieved their goal; on 14 September 2015 two detectors known as Advanced LIGO finally managed to ensnare gravitational waves.  [more]

Gravitational waves

Gravitational waves detected 100 years after Einstein's prediction

LIGO opens new window on the universe with observation of gravitational waves from colliding black holes /key contributions from Max Planck Society and Leibniz Universität Hannover researchers

For the first time, scientists have observed ripples in the fabric of spacetime called gravitational waves, arriving at the earth from a cataclysmic event in the distant universe. This confirms a major prediction of Albert Einstein’s 1915 general theory of relativity and opens an unprecedented new window onto the cosmos.

Collision in the computer: this simulation shows the two black holes with 29 and 36 solar masses, which dance around each other and will merge in a few moments. They emit gravitational waves – which have been observed in terrestrial detectors. Zoom Image
Collision in the computer: this simulation shows the two black holes with 29 and 36 solar masses, which dance around each other and will merge in a few moments. They emit gravitational waves – which have been observed in terrestrial detectors. [less]

Gravitational waves carry information about their dramatic origins and about the nature of gravity that cannot otherwise be obtained. Physicists have concluded that the detected gravitational waves were produced during the final fraction of a second of the merger of two black holes to produce a single, more massive spinning black hole. This collision of two black holes had been predicted but never observed.

The gravitational waves were detected on September 14, 2015 at 5:51 a.m. Eastern Daylight Time (9:51 a.m. UTC) by both of the twin Laser Interferometer Gravitational-wave Observatory (LIGO) detectors, located in Livingston, Louisiana, and Hanford, Washington, USA. The LIGO Observatories are funded by the National Science Foundation (NSF), and were conceived, built, and are operated by Caltech and MIT.

The discovery, accepted for publication in the journal Physical Review Letters, was made by the LIGO Scientific Collaboration (which includes the GEO Collaboration and the Australian Consortium for Interferometric Gravitational Astronomy) and the Virgo Collaboration using data from the two LIGO detectors.

Researchers at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute; AEI) in Hannover and Potsdam, Germany, and from the Institute for Gravitational Physics at Leibniz Universität Hannover (LUH) have made crucial contributions to the discovery in several key areas: development and operation of extremely sensitive detectors pushed to the limits of physics, efficient data analysis methods running on powerful computer clusters, and highly accurate waveform models to detect the signal and infer astrophysical information from it.

Advanced detector techniques from GEO600

Hightech in the open field: The cabins of GEO600 look like building containers in the countryside near Hannover. This is where researchers are searching for gravitational waves with very sophisticated measures. Zoom Image
Hightech in the open field: The cabins of GEO600 look like building containers in the countryside near Hannover. This is where researchers are searching for gravitational waves with very sophisticated measures. [less]

The GEO collaboration includes Max Planck and Leibniz Universität researchers together with UK colleagues. They designed and operate the GEO600 gravitational-wave detector near Hannover, Germany. It is used as a think tank and testbed for advanced detector techniques.

Most of the key technologies that contributed to the unprecedented sensitivity of Advanced LIGO (aLIGO) and enabled the discovery have been developed and tested within the GEO collaboration. Examples of these are signal recycling, resonant sideband extraction, and monolithic mirror suspensions. AEI researchers together with the Laser Zentrum Hannover e.V. also developed and installed the aLIGO high-power laser systems, which are crucial for the high-precision measurements.

“Scientists have been looking for gravitational waves for decades, but we’ve only now been able to achieve the incredibly precise technologies needed to pick up these very, very faint echoes from across the Universe,” says Karsten Danzmann, director at the Max Planck Institute for Gravitational Physics in Hannover and director of the Institute for Gravitational Physics at Leibniz Universität Hannover. “This discovery would not have been possible without the efforts and the technologies developed by the Max Planck, Leibniz Universität, and UK scientists working in the GEO collaboration.”

Computing power and analysis methods for the discovery

Illuminating research: scientists have developed innovative technologies for the detector GEO600,  which are also used in other systems of this type worldwide. Zoom Image
Illuminating research: scientists have developed innovative technologies for the detector GEO600,  which are also used in other systems of this type worldwide. [less]

Max Planck scientists developed and implemented advanced and efficient data analysis methods to search for weak gravitational-wave signals in the aLIGO detector data streams and carried out most of the production analysis. In addition, the majority of the computational resources for the discovery and analysis of the Advanced LIGO data were provided by Atlas, the most powerful computer cluster in the world designed for gravitational-wave data analysis, operated by the AEI. Atlas has provided more than 24 million CPU core hours for the analysis of Advanced LIGO data.

“I am proud that the first two scientists to look at the signal were at the Max Planck Institute for Gravitational Physics and that our institute played a leading role in this exciting discovery,” says Bruce Allen, director at the Max Planck Institute for Gravitational Physics in Hannover. “Einstein himself thought gravitational waves were too weak to detect, and didn’t believe in black holes. But I don’t think he’d have minded being wrong!“

Accurate models of gravitational waves pave the way

Max Planck researchers developed highly accurate models of gravitational waves that black holes would generate in the final process of orbiting and colliding with each other. These waveform models were implemented and employed in the continuing search for binary coalescences in LIGO data. It is this search that observed the black-hole merger known as GW150914 with greater than 5-sigma confidence.

Max Planck scientists also used the same waveform models to infer the astrophysical parameters of the source, such as the masses and spins of the two black holes, the binary’s orientation and distance from Earth, and the mass and spin of the enormous black hole that the merger produced. The waveform models were also employed to test whether GW150914 is consistent with predictions from general relativity.

“We spent years modeling the gravitational-wave emission from one of the most extreme events in the Universe: pairs of massive black holes orbiting with each other and then merging. And that’s exactly the kind of signal we detected!” says Alessandra Buonanno, director at the Max Planck Institute for Gravitational Physics in Potsdam. “It is overwhelming to see how exactly Einstein’s theory of relativity describes reality. GW150914 gives us a remarkable opportunity to see how gravity operates under some of the most extreme conditions possible.”

Superbrain: the computer cluster Atlas, operated by the Max Planck Institute for Gravitational Physics, is one of the most powerful mainframes for data analysis of gravitational waves. Zoom Image
Superbrain: the computer cluster Atlas, operated by the Max Planck Institute for Gravitational Physics, is one of the most powerful mainframes for data analysis of gravitational waves. [less]

LIGO research is carried out by the LIGO Scientific Collaboration (LSC), a group of more than 1000 scientists from universities around the United States and in 14 other countries. More than 90 universities and research institutes in the LSC develop detector technology and analyze data; approximately 250 students are strong contributing members of the collaboration.

The LSC detector network includes the LIGO interferometers and the GEO600 detector. The GEO team includes scientists at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute, AEI), Leibniz Universität Hannover, along with partners at the University of Glasgow, Cardiff University, the University of Birmingham, other universities in the United Kingdom, and the University of the Balearic Islands in Spain.

LIGO was originally proposed as a means of detecting these gravitational waves in the 1980s by Rainer Weiss, professor of physics, emeritus, from MIT; Kip Thorne, Caltech’s Richard P. Feynman Professor of Theoretical Physics, emeritus; and Ronald Drever, professor of physics, emeritus, also from Caltech.

Virgo research is carried out by the Virgo Collaboration, consisting of more than 250 physicists and engineers belonging to 19 different European research groups: 6 from Centre National de la Recherche Scientifique (CNRS) in France; 8 from the Istituto Nazionale di Fisica Nucleare (INFN) in Italy; 2 in The Netherlands with Nikhef; the Wigner RCP in Hungary; the POLGRAW group in Poland and the European Gravitational Observatory (EGO), the laboratory hosting the Virgo detector near Pisa in Italy.

The discovery was made possible by the enhanced capabilities of Advanced LIGO, a major upgrade that increases the sensitivity of the instruments compared to the first generation LIGO detectors, enabling a large increase in the volume of the universe probed – and the discovery of gravitational waves during its first observation run. The US National Science Foundation leads in financial support for Advanced LIGO.

Funding organizations in Germany (Max Planck Society), the U.K. (Science and Technology Facilities Council, STFC) and Australia (Australian Research Council) also have made significant commitments to the project. Several of the key technologies that made Advanced LIGO so much more sensitive have been developed and tested by the German UK GEO collaboration. Significant computer resources have been contributed by the AEI Hannover Atlas Cluster, the LIGO Laboratory, Syracuse University, and the University of Wisconsin-Milwaukee.

Several universities designed, built, and tested key components for Advanced LIGO: The Australian National University, the University of Adelaide, the University of Florida, Stanford University, Columbia University of New York, and Louisiana State University.

LSC / KNI

 
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