Black holes really are holes - objects without a surface - say Drs Christine Done and Marek Gierlinski in a paper accepted for publication in the Monthly Notices of the Royal Astronomical Society. Having an "event horizon" rather than a surface is the property that makes something a black hole but, by definition, its impossible ever to see one directly. However, these new results give direct evidence of the existence of such holes in spacetime.
Drs Done and Gierlinski set out to track down the signatures of event horizons by looking for differences between objects thought to be black holes and collapsed bodies of a different kind that are only slightly less extreme - neutron stars. Any material captured by the strong gravity of either type of object will spiral inwards in much the same way, reaching speeds of up to half the speed of light and transforming some of the immense gravitational energy into X-ray emission. The crucial difference is that, in the case of a black hole, material should simply pour into the hole, taking its remaining energy with it and disappearing forever, whereas with a neutron star material smashes onto the surface, releasing whatever energy is left. As a consequence, the X-ray emissions from neutron stars and black holes should look different.
"The idea is simple in theory, and has been known for a long time, but until now it has been hard to put into practice because the X-ray emission even from a single type of object can show a bewildering variety of properties that are not well understood," says Chris Done.
Dr Chris Done | alfa
K-State study reveals asymmetry in spin directions of galaxies
03.06.2020 | Kansas State University
The cascade to criticality
03.06.2020 | ETH Zurich Department of Physics
An analysis of more than 200,000 spiral galaxies has revealed unexpected links between spin directions of galaxies, and the structure formed by these links...
Two prominent X-ray emission lines of highly charged iron have puzzled astrophysicists for decades: their measured and calculated brightness ratios always disagree. This hinders good determinations of plasma temperatures and densities. New, careful high-precision measurements, together with top-level calculations now exclude all hitherto proposed explanations for this discrepancy, and thus deepen the problem.
Hot astrophysical plasmas fill the intergalactic space, and brightly shine in stellar coronae, active galactic nuclei, and supernova remnants. They contain...
In living cells, enzymes drive biochemical metabolic processes enabling reactions to take place efficiently. It is this very ability which allows them to be used as catalysts in biotechnology, for example to create chemical products such as pharmaceutics. Researchers now identified an enzyme that, when illuminated with blue light, becomes catalytically active and initiates a reaction that was previously unknown in enzymatics. The study was published in "Nature Communications".
Enzymes: they are the central drivers for biochemical metabolic processes in every living cell, enabling reactions to take place efficiently. It is this very...
Early detection of tumors is extremely important in treating cancer. A new technique developed by researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from normal tissue. The work is published May 25 in the journal Nature Nanotechnology.
researchers at the University of California, Davis offers a significant advance in using magnetic resonance imaging to pick out even very small tumors from...
Microelectronics as a key technology enables numerous innovations in the field of intelligent medical technology. The Fraunhofer Institute for Biomedical Engineering IBMT coordinates the BMBF cooperative project "I-call" realizing the first electronic system for ultrasound-based, safe and interference-resistant data transmission between implants in the human body.
When microelectronic systems are used for medical applications, they have to meet high requirements in terms of biocompatibility, reliability, energy...
19.05.2020 | Event News
07.04.2020 | Event News
06.04.2020 | Event News
03.06.2020 | Medical Engineering
03.06.2020 | Physics and Astronomy
03.06.2020 | Physics and Astronomy