The Supreme Personality of Godhead, Viṣṇu, is always the protector of His devotees, who are also known as demigods. The controlling demigods are most obedient to Lord Viṣṇu, although they also want material sense enjoyment, and that is why they are called demigods, or almost godly. Although Rāhu attempts to attack both the sun and the moon, they are protected by Lord Viṣṇu. Being very afraid of Lord Viṣṇu’s cakra, Rāhu cannot stay in front of the sun or moon for more than a muhūrta (forty-eight minutes). The phenomenon that occurs when Rāhu blocks the light of the sun or moon is called an eclipse.