THE GALAXIES INFORMATION

                                                                 GALAXIES

                                      A GALAXY IS HUGE MASS OF STARS

nebulae and interstellar material. The smallest galaxies contain about 100,000 stars, while the largest contain up to 3,000 billion stars.

 There are three main types of galaxy, classified according  to their shape: elliptical, which are oval shaped; spiral, which have arms spiralling outwards from a central bulge (those whose arms spiral from a bar-shaped bulge are called spirals); and irregluar , which have no obvious shape. sometime, the shape of a galaxy is distorted by a collision with other galaxy. Quasars (quasi-stellar objects ) are thought to be galactic nuclei but are so far away that their exact nature is still uncertain. They are compact, highly luminous objects in the outer reaches of the known Universe: while the furthest known "ordinary" galaxies are about 12 billion light years away, the furthest known quasar about 13 billion light years away.

 Active galaxis, duch as seyfert galaxies and radio galaxies, emit intense radiation. In a Seyfert galaxy, this radiations comes from the galactic nucleus; in aradio galaxy, it also comes from huge lobes on either side of the galaxies and quasars is thought to be caused by material falling into centarl black holes