☄️ Astronomical Basis of Rahu & Ketu (Lunar Nodes)

  

In astronomy, Rahu and Ketu correspond to the two lunar nodes—the points where the Moon’s orbit intersects the Earth’s orbital plane (the ecliptic).

🌕 Rahu – Ascending Node  

Rahu corresponds to the point where the Moon crosses the ecliptic from south to north.

- This is called the “ascending node”  

- It represents the point of upward crossing relative to the ecliptic plane  

- In orbital terms, it marks where the Moon’s latitude changes from negative to positive  

🌑 Ketu – Descending Node  

Ketu corresponds to the point where the Moon crosses the ecliptic from north to south.

- This is called the “descending node”  

- It represents the downward crossing relative to the ecliptic plane  

- Here, the Moon’s latitude changes from positive to negative  

🌀 Why They Appear Retrograde  

Rahu and Ketu are not physical celestial bodies—they are mathematical intersection points. Because of the way the lunar nodes regress along the ecliptic due to orbital mechanics, they appear to move in a retrograde (westward) direction from an Earth-centered perspective.

⚖️ Key Principle  

Unlike planets, Rahu and Ketu have no physical mass or luminosity. Their significance in astrology is symbolic and mathematical, representing eclipse points and the interaction between solar and lunar planes rather than tangible celestial objects.