... A solar prominence is a cloud of solar gas held just above the surface by the Sun's magnetic field. ... Dust usually shows its presence by blocking out light emitted from stars or nebulae behind it, sometimes creating the illusion of a horse's head or a sombrero hat. ... Centaurus A: X-Rays from an Active Galaxy . ... Its core hidden from optical view by a thick lane of dust, the giant elliptical galaxy Centaurus A was among the first objects observed by the orbiting Chandra X-ray Observatory. ...