This image shows the eruption of a galactic “super-volcano” in the massive galaxy M87, as witnessed by NASA's Chandra X-ray Observatory and NSF's Very Large Array (VLA). At a distance of about 50 million light years, M87 is relatively close to Earth and lies at the center of the Virgo cluster, which contains thousands of galaxies. The cluster surrounding M87 is filled with hot gas glowing in X-ray light (and shown in blue) that is detected by Chandra. As this gas cools, it can fall toward the galaxy's center where it should continue to cool even faster and form new stars. However, radio observations with the VLA (red) suggest that in M87 jets of very energetic particles produced by the black hole interrupt this process. These jets lift up the relatively cool gas near the center of the galaxy and produce shock waves in the galaxy's atmosphere because of their supersonic speed. The interaction of this cosmic “eruption” with the galaxy's environment is very similar to that of the Eyjafjallajokull volcano in Iceland that occurred in 2010. With Eyjafjallajokull, pockets of hot gas blasted through the surface of the lava, generating shock waves that can be seen passing through the grey smoke of the volcano. This hot gas then rises up in the atmosphere, dragging the dark ash with it. This process can be seen in a movie of the Eyjafjallajokull volcano where the shock waves propagating in the smoke are followed by the rise of dark ash clouds into the atmosphere. In the analogy with Eyjafjallajokull, the energetic particles produced in the vicinity of the black hole rise through the X-ray emitting atmosphere of the cluster, lifting up the coolest gas near the center of M87 in their wake. This is similar to the hot volcanic gases drag up the clouds of dark ash. And just like the volcano here on Earth, shockwaves can be seen when the black hole pumps energetic particles into the cluster gas. The energetic particles, coolest gas and shockwaves are shown in a labeled version. Credits: X-ray: NASA/CXC/KIPAC/N. Werner et al Radio: NSF/NRAO/AUI/W. Cotton
Antes se creía que los adultos mayores perdían neuronas cada día y que la conexión de nuevos circuitos neurales era imposible. Sin embargo, investigaciones recientes indican que muchos factores —entre ellos el ejercicio físico y mental— pueden generar nuevos circuitos neurales y de esta manera ayudar a mantener una efectiva lucidez mental. Ciertas destrezas, como la reacción rápida y la memoria, tienden a declinar cuando se envejece, pero esos declinamientos son muy leves y no interfieren con la vida productiva, debido a que la experiencia y sabiduría de la gente mayor puede contrarrestar ese declinamiento. La investigación sugiere que la gente que le pone nuevos retos a su cerebro, tiene más probabilidad de mantener la función mental activa cuando envejece, y que incluso puede alejar el riesgo de Alzheimer. Por otra parte, dado que la actividad física reduce el estrés y la depresión actúa como un protector de las funciones cerebrales. Los estudios realizados en personas centenarias, s
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