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
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17.12.2018 | Universität Basel
Researchers from the University of Basel have reported a new method that allows the physical state of just a few atoms or molecules within a network to be controlled. It is based on the spontaneous self-organization of molecules into extensive networks with pores about one nanometer in size. In the journal ‘small’, the physicists reported on their investigations, which could be of particular importance for the development of new storage devices.
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A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.
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A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.
Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...
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