Rahu isn't a planet; it's the point where the Moon's orbit crosses the ecliptic heading north. In the myth it's the severed head of an asura — a head with no body, so it can never be full. That image is its mechanism: Rahu governs craving, obsession, what you don't yet have, foreign lands, technology, the unorthodox, sudden rises.
It's forever opposite Ketu, the south node, and the two make an axis: Ketu is what you know so well you needn't learn it, Rahu is what this life is meant to swallow forward. So wherever Rahu sits there's a strong 'want', and not a very rational one — it magnifies like a shadow. The tradition says Rahu 'acts like Saturn': what it brings comes fast and unstable, and needs Saturn's kind of discipline to hold.
Where you'll recognise it: an unexplained fixation on a certain field, a pull toward the world outside, wanting that never feels satisfied, things sometimes suddenly gained and suddenly lost. Running well, Rahu is your most breakthrough part: entering where no one has, rising fast in a new field, a nose for the future. Stuck, it's being led by appetite — chasing without end, illusion, wanting mistaken for needing. Rahu's lesson is to taste before you swallow: the direction it gives is right; the speed is yours to control.
