Before moving forward to understand several anomalies and events in the vast universe. You must know certain definitions and terminologies. This is a very important lecture hence I recommend everyone to not skip it. Several definitions and terminologies discussed in this session are ;

Black body,black hole, Cosmic microwave background radiation,cosmic rays,supernova,Aurora Australlis & Aurora Boreallis,binary star,meteor,meteor shower,meteorite,meteoroid,nebula,Red dwarf and Red giant, Redshift, Pulsar,Dark matter,light year,neutron star.