The Nodes of the Moon are crucial points in your birth chart to understand. They are points in space that are keys to understanding and working with your incarnational destiny.
Rahu is the North Node of the Moon. Ketu is the South Node of the Moon. They are always opposite each other in the heavens.
Astronomically, the Nodes are the intersection points in space of the apparent orbits of the Sun and the Moon around the Earth. They are the eclipse points. They are so powerful they can devour the Sun or the Moon at an eclipse.
The Nodes of the Moon: Past Lives and Incarnational Life Purpose:
Basically, Ketu represent our past lives, the position we come in to at birth from our past lives.
Rahu on the other hand, is the thrust of our incarnational direction of manifestation this time.
The energy of Rahu is driven and demonic and he drives us across the chart from Ketu. If he were not so driven we wouldn’t get to our destination. But if we don’t purify our rahu, we won’t reach our destination.
Ketu is the tail and body of the celestial serpent (and so has no head). Rahu is the head of the celestial serpent (and so has no heart). This is all explained in the Myth of the ‘Churning of the Milk Ocean’ that I talk about in Pt 2 of my Ketu Blog Post (see links at the foot of this blog).
Crucially, in the war between Gods and Demons, the realisation is that both must cooperate, the churning of the ocean, for the transmutation of the poisons that are released.
Rahu: Description and Energy:
Rahu creates smoke, has a dark body, resides in forests and engenders fear. He is airy and vata in constitution.
The energy of Rahu is animal-like, insatiable and instinctual, not governed by conscious will or intelligence. It is outward rather than inward. Rahu is obsession, ambition, compulsions and insatiable desire; he can offer material success (which can be temporary).
In fact, a strong Rahu usually brings material success and worldly power (though not necessarily inner fulfillment).
And strong Rahu can bring psychic powers