Cistus, with its many hybrids and cultivars, is commonly encountered as a garden flower. The common name rockrose is applied to the species, a name also shared by the related genera Halimium, Helianthemum and Tuberaria, all in the family Cistaceae. The common name gum cistus is applied to resin-bearing species, especially C. ladanifer.
Quasars are part of a class of objects known as active galactic nuclei (AGN). Other classes include Seyfert galaxies and blazars. All three require supermassive black holes to power them.
Quasars emit energies of millions, billions, or even trillions of electron volts. This energy exceeds the total of the light of all the stars within a galaxy. The brightest objects in the universe, they shine anywhere from 10 to 100,000 times brighter than the Milky Way.