Max Planck Institute for Gravitational Physics (Hanover)

Ten new neutron stars allow new tests of extreme stellar physics and the theory of relativity

High-precision laser source from Hannover for the ETpathfinder in Maastricht

When a black hole and a neutron star merge

Radio telescope discovers system of a pulsar and an unknown object at the boundary between black hole and neutron star

Observation of multiple ringdown modes in a black hole merger

The largest astronomical observatory is so large that it won’t fit on Earth. It’s called Lisa, and it will be able to detect when a 2.5-million-kilometer segment of space shrinks by even one atomic diameter. Researchers at the Max Planck Institute for Gravitational Physics in Hanover and Potsdam helped develop the gravitational-wave detector. By observing cosmic waves, they hope to gain an insight into strange processes deep in outer space.

It should not actually exist - a black hole with a mass 85 times that of our sun. But that is precisely what astronomers have discovered. Apparently, this heavyweight used to be part of a binary star system before it merged with its equally massive partner. The resulting space-time quake unleashed gravitational waves that are posing many a puzzle for researchers at the Max Planck Institute for Gravitational Physics in Potsdam and Hanover.

Humankind has always been fascinated by the mythical concept of a cyclic universe that ends in a cosmic conflagration and is then reborn. Modern Big Bang theory that suggests an infinitely expanding universe rules out this possibility. But has the final word been spoken on the issue? Anna Ijjas investigates this fundamental question at the Max Planck Institute for Gravitational Physics in Hannover.

The Einstein@Home project makes it possible for anyone to search for gravitational waves on their own PC, laptop or smartphone and thus become scientific explorer themselves. Bruce Allen, Director at the Max Planck Institute for Gravitational Physics in Hannover, is the founder of this citizen science project. The software is now also used to track down pulsars in big data. Researchers from the Max Planck Institute for Radio Astronomy in Bonn are also involved in this search.

Albert Einstein was right: gravitational waves really do exist. They were detected on September 14, 2015. This, on the other hand, would have surprised Einstein, as he believed they were too weak to ever be measured. The researchers were therefore all the more delighted - particularly those at the Max Planck Institute for Gravitational Physics, which played a major role in the discovery.

The planned “Laser Interferometer Space Antenna” (LISA) space mission will observe gravitational waves in space and thus write a new chapter of astronomy. After decades of preparation, LISA is now on the home stretch. The three satellites are scheduled to be built starting in 2024 and will be launched into space in the early 2030s. Researchers at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute) founded the project, accompanied it through ups and downs, and will continue to play a crucial role in realizing the mission.

The mystery of a gamma-ray source known for two decades has finally been solved. An extremely rapidly rotating neutron star in a binary system is the source of the gamma rays. For this discovery, 10 years of gamma-ray data from NASA’s Fermi Gamma-ray Space Telescope has been analysed, using the distributed volunteer computing project Einstein@Home. The thorough study of this neutron star and its companion using gamma-ray data and optical observations reveals a truly extreme binary system. Material evaporated from the companion star likely blocks radio waves from the neutron star.

On 22 May 2018, the two GRACE Follow-On satellites launched into Earth orbit on a Falcon-9 rocket. The aim: to continue the GRACE satellite measurements, which is important among other things for climate research, by monitoring the Earth's gravitational field. On board: A laser interferometer from the Max Planck Institute for Gravitational Physics (Albert Einstein Institute; AEI) in Hanover, which will serve as a model for future missions and as a step towards the LISA gravitational wave observatory. The first very promising preliminary results are already coming in before the science phase.

On 14 September 2015, the Advanced LIGO instruments detected gravitational waves for the first time ever. The signal came from the merger of two black holes, each with the mass of about 30 Suns, in a distance of 1.3 billion light-years to Earth. Albert Einstein had predicted the existence of these ripples in spacetime in 1916. The first hours of this discovery of the century took place at the Max Planck Institute for Gravitational Physics in Hannover in Bruce Allen's “Observational Relativity and Cosmology” division. The authors were also the first persons to see the signal.

The LISA Pathfinder satellite mission demonstrates core technologies for future gravitational-wave observatories in space like eLISA. These observatories will study low-frequency gravitational waves, which are emitted by, e. g., binary supermassive black holes or galactic binary stars. LISA Pathfinder was launched on December 3, 2015, and has commenced its science operations in March 2016. LISA Pathfinder will lead to a comprehensive model of all significant physical noise sources that can be extrapolated to the eLISA mission.