Rahu and Ketu denote the two points of intersection of the paths of the Sun and the Moon as they move around the celestial sphere. Therefore, Rahu and Ketu are respectively called the north and the south lunar nodes. The fact that eclipses occur when Sun and Moon are at one of these points shows swallowing of the Sun and Moon causing either a solar or a lunar eclipse. In Sanskrit this is known as grahanam or seizing.
To Protect the Balance of the Creation at this Point Vishnu Protects Sun Moon and Shiva Protects Rahu Ketu whenever there is conflict between them
https://freeglobaluniversity.blogspot.com/search/label/SunMoon
https://freeglobaluniversity.blogspot.com/search/label/Shadow
