NEBULA
A nebula is an Interstellar cloud in space. It is made of Helium gas, dust , hydrogen and plasma. It was formed by a clump of interstellar medium collapse due to gravity attraction. a nebula is caused by a supernova.
SUPERNOVA
A supernova is when a star comes to the end of its time. The star explodes into the air this is knows as a supernova. The supernova can light up the sky for weeks.