What are quasars?Discuss

When a supermassive black hole at the center of a galaxy accretes matter rapidly, the resulting gravitational effects can make the black hole’s surroundings glow brighter than all that galaxy’s stars put together. Such systems are called active galaxies; and in extreme cases at large distances these objects look like stars, and thus are called quasi-stellar objects or quasars. In this lab exercise, you will investigate these amazing objects. Please submit your answers on the answer sheets at the end of this document.
What are quasars?