All the planets in Astrology moves around Sun in a elliptical (or egg like) orbit. However we saw in last post that Rahu and Ketu are not physical planet but mathematical points.
The movement of these point is not in a elliptical form but rather quite erratic like a snake. Let's see how -
We know Rahu is the point where Moon intersect Earth – Sun plane in its journey upwards and Ketu is point of intersection in Moon’s journey downwards. To trace the path of Rahu and Ketu we need to connect the consecutive points of intersection. And in this consecutive points there are 2 variables –
Between 2 consecutive points of intersection Moon moves in Elliptical motion (like an egg) and
Sun – Earth plane keeps moving up and down (due to Earth’s motion up and down which is called “Uttarayan” – Northward and “Dakshinayana” – Southward motion of earth)
Due to these variations the consecutive points of Rahu and Ketu do not follow a pattern of Ellipse but a little random. E.g. –
So we see the points of Rahu and Ketu move erratically like snake. If we join more points we get something like this –
No wonder why in Vedic Astrology Rahu and Ketu are equated with Snakes. Also Rahu as Snake Head and Ketu and rest of the body.
PS: In reality periodically some intersection points (Rahu and Ketu) goes backward then the earlier one which makes this path further complicated. However overall motion is in one direction.