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.
Quasar Cluster: Largest Object In The Universe May Disprove Einstein's Cosmological Principle. Astronomers have discovered the largest object in the universe. In fact it's so big, it might challenge a key principle of cosmology predicted by none other than Einstein himself. The object is a group of quasars from that four billion light years across. Together they form the largest structure in the universe, researchers at the University of Central Lancashire reported in the journal of the Royal Astronomical Society. The quasar structure is more than 1,600 times as big as our galaxy, the Milky Way.