This brief video explains our current understanding of quasars, and how the generate so much energy and are able to be seen from so far away. As the video discusses, when quasars were first observed in the 1960’s, there was a great deal of interest generated about these distant yet incredibly bright objects. As we now know today, quasars, blazars, and radio galaxies are actually examples of the same phenomena, just viewed from different angles.
The phenomena that generates these amazingly powerful objects is known as an active galactic nucleus. The video explains that while all galaxies are thought to have a supermassive black hole at their center, not all of these black holes are “feeding”. When galactic material gets too close to the black hole, it forms an accretion disk and heats up to millions of degrees as particles spiral into the black hole. The rapid movement of these hot, charged particles generates jets of energy perpendicular to the plane of rotation, which extend millions of light years into the universe. These beams of energy can be seen from across the galaxy. Up until recently, quasars couldn’t be used to estimate cosmic distances, as they vary in how much light they emit at each wavelength. In 2012, however, a team of researchers found a trend in the light emitted by various quasars that will hopefully lead to being able to use them as “standard candles,” which would allow astrophysicists to use them to better estimate cosmic distances and, ultimately the age of the universe.