Final answer:
The Saros cycle refers to the 18+ year cycle of lunar and solar eclipses. It is linked to the synchronized movements of the Sun and Moon across the celestial sphere and especially their positions on the ecliptic.
Step-by-step explanation:
The Saros cycle describes B. the 18+ year cycle of lunar and solar eclipses. This cycle is essential in predicting when eclipses will occur. The Sun and the Moon both move along a path on the celestial sphere known as the ecliptic, with the Sun taking about a month to pass through each sign of the zodiac and completing the journey in one year. The Moon also follows a synodic period, which is the time it takes to cycle through its phases (about 29.53 days), because this relies on the position of the Sun. A solar eclipse is caused by the Moon passing in front of the Sun, which can only occur at the time of the new moon. The synchronization of Earth's rotation with the Moon's revolution around Earth (synchronous rotation) also plays a significant role in the patterns of eclipses witnessed on Earth.