What are major and minor ritual impurity (janabah) and how does one perform ghusl (ritual bathing) for them?

Janabah is a state that afflicts the body, preventing one from performing prayer and staying in the mosque. It is a spiritual impediment that invalidates the prayer. The term janabah is applied to one who has emitted semen or engaged in sexual intercourse. There is no such thing as minor or major janabah; rather, jurists use the term "major ritual impurity" (al-hadath al-akbar) to refer to janabah, and "minor ritual impurity" (al-hadath al-asghar) for the other invalidators of ablution. The method of ritual bathing (ghusl) for janabah and menstruation is the same.