End time (also called end times, end of time, end of days, last days, final days, or eschaton) is a time period described in the eschatologies of the dominant world religions, both Abrahamic and non-Abrahamic. The Abrahamic faiths maintain a linear cosmology, with end time scenarios containing themes of transformation and redemption. In Judaism, the term "end of days" is a reference to the Messianic Age, and includes an in-gathering of the exiled diaspora, the coming of the mashiach, olam haba, and resurrection of the Tsadikim. In Christianity, end time is depicted as a time of tribulation that precedes the second coming of Christ, who will face the emergence of the Antichrist and usher in the Kingdom of God. In Islam, the Yawm al-Qiyāmah or Yawm ad-Din, the Day of Judgement, is preceded by the appearance of al-Mahdi atop a white stallion. With the help of Isa, Mahdi will then triumph over Masih ad-Dajjal. The non-Abrahamic faiths have more cyclical eschatologies regarding end time, characterized by decay, redemption and rebirth. In Hinduism, end time is foretold as when Kalki, the final incarnation of Vishnu, descends atop a white horse and bring an end to the current Kali Yuga. In Buddhism, the Buddha predicted that his teachings would be forgotten after 5,000 years, followed by turmoil. A bodhisattva named Maitreya will appear and rediscover the teaching of dharma. The ultimate destruction of the world will then come through seven suns. Since the discovery of deep time and the age of the Earth, scientific discourse about end time has centered around the ultimate fate of the universe. Theories have included the Big Rip, Big Crunch, Big Bounce, and Big Freeze.