Most people think of black holes as giant vacuum cleaners sucking in everything that gets too close. But the supermassive black holes at the centers of galaxies are more like cosmic engines, converting energy from infalling matter into intense radiation that can outshine the combined light from all surrounding stars. If the black hole is spinning, it can generate strong jets that blast across thousands of light-years and shape entire galaxies. These black hole engines are thought to be powered by magnetic fields. For the first time, astronomers have detected magnetic fields just outside the event horizon of the black hole at the center of our Milky Way galaxy.
“Understanding these magnetic fields is critical. Nobody has been able to resolve magnetic fields near the event horizon until now,” says lead author Michael Johnson of the Harvard-Smithsonian Center for Astrophysics (CfA). The results appear in the Dec. 4th issue of the journal Science.
Smart Bandage Signals Infection by Turning Fluorescent
Bacterial infection is a fairly common and potentially dangerous complication of wound healing, but a new “intelligent” dressing that turns fluorescent green to signal the onset of an infection could provide physicians a valuable early-detection system.
Researchers in the United Kingdom recently unveiled a prototype of the color-changing bandage, which contains a gel-like material infused with tiny capsules that release nontoxic fluorescent dye in response to contact with populations of bacteria that commonly cause wound infections.
Led by Toby Jenkins, a professor of biophysical chemistry at the University of Bath, the inventors of the new bandage, which has not yet been tested in humans, say it could be used to alert health-care professionals to an infection early enough to prevent the patient from getting sick. In some cases it may even be able help avoid the need for antibiotics, says Jenkins.