Astronomers using ESO’s MUSE instrument on the Very Large Telescope in Chile have discovered a star in the cluster NGC 3201 that is behaving very strangely. It appears to be orbiting an invisible black hole with about four times the mass of the sun — the first such inactive stellar-mass black hole found in a globular cluster. This important discovery impacts on our understanding of the formation of these star clusters, black holes, and the origins of gravitational wave events.This artist’s impression shows how the star and its massive but invisible black hole companion may look, in the rich heart of the globular star cluster. Credit: ESO/L. Calçada

Astronomers using ESO’s MUSE instrument on the Very Large Telescope in Chile have discovered a star in the cluster NGC 3201 that is behaving v...

Photocatalytic overall pure-water splitting using the 2D heterostructures of BP/BiVO4 without any sacrificial agents under visible light irradiation.

Researchers combined 2 2D materials – black phosphorus and bismuth vanadate – to form a biologically inspired water-splitting catalyst. Normal sunlight could drive the reactions and careful design of the catalyst enabled the expected ratio of hydrogen and oxygen production. Burning hydrogen produces harmless water with the potential to eliminate CO2 emissions and their environmental burden. In pursuit of technologies that could lead to a breakthrough in achieving a hydrogen economy, a key issue is making hydrogen cheaply...

In 2014, astronomers using the NASA/ESA Hubble Space Telescope found that this enormous galaxy cluster contains the mass of a staggering three million billion suns — so it’s little wonder that it has earned the nickname of “El Gordo” (“the Fat One” in Spanish)! Known officially as ACT-CLJ0102-4915, it is the largest, hottest, and brightest X-ray galaxy cluster ever discovered in the distant universe. Credit: ESA/Hubble & NASA, RELICS

In 2014, astronomers using the NASA/ESA Hubble Space Telescope found that this enormous galaxy cluster contains the mass of a staggering three million billion suns – so it’s little wonder that it has earned the nickname of “El Gordo” (“the Fat One” in Spanish)! Known officially as ACT-CLJ0102-4915, it is the largest, hottest, and brightest X-ray galaxy cluster...

Gravitational-wave emission from a collapsing star

Astrophysicists at Goethe University Frankfurt set a new limit for the maximum mass of neutron stars: It cannot exceed 2.16 solar masses. Since their discovery in the 1960s, scientists have sought to answer an important question: How massive can neutron stars actually become? By contrast to black holes, these stars cannot gain in mass arbitrarily; past a certain limit there is no physical force in nature that can counter their enormous gravitational force.

With a radius of about 12 km and a mass that can be twice as large as that of the sun, neutron stars are amongst the densest objects in the Universe, producing gravitational fields comparable to those of black holes. Whilst most neutron stars have a mass of around 1...