This time-lapse movie of an extragalactic jet was assembled from 20 years of Hubble Space Telescope observations of the core of the elliptical galaxy NGC 3862. The blowtorch of ejected plasma is powered by energy from a supermassive black hole at the center of the galaxy. Once the movie was made, astronomers could easily follow the motion of a string of knots moving along the jet. They were surprised to see that one of the knots caught up with and "rear-ended" the knot in front of it, causing it to brighten. The new analysis suggests that shocks produced by collisions within the jet further accelerate particles that are confined to a narrowly focused beam of radiation. The jet is blasting across space at nearly the speed of light.
Publication: May 27, 2015