Graha vs. Planets

Vedic Astrology considers graha [ग्रह], rather than ‘planets’.

Planets, as we know, are those that revolve around the Sun.

The word “Planet” is derived from Greek word “planeta”, which refers to that which wanders or moves.

Planets are thus considered to be those celestial or astronomical bodies that orbit around the Sun.

Well, Sun is actually a Star…isn’t it.

And, don’t we still teach our children that the Sun rises in the East and sets in the West – only to tell them later that the Sun is stationary and Earth moves around it…Anyways!

According to Vishnu Purana:

अहोरात्र व्यवस्थाकारण भग्वान्रवि ...

the cause of day and night is the Sun God.....

नैवास्तमर्कस्य नोदया सर्वदा सतः।
उदयास्तमनाख्यं हि दर्शनादर्शनं रवेः॥

The Sun neither Sets, nor does it ever Rise,
The rising and the setting (of the Sun) is (in effect) due to it being seen or not seen.

The sages knew that the Sun only appears to move in the sky.

In Vedic texts, the term used is graha [ग्रह].

Graha means that which can ‘seize’ or ‘get hold of’ or ‘grasp’ – can cause grahṇa [ग्रह्ण].

As per BPHS {bṛhat parāśara horā śāṣtra - बृहत् पराशर होरा शाष्त्र}:

गच्छन्तो भानि गृह्णन्ति सततं ये तु ते ग्रहः

i.e. those which move through the zodiac, while getting hold of, are called ‘graha.

What does a graha grasp?

As the graha moves through the skies (as seen from the earth), it is seen to move over (appearing to get hold of) a particular constellation (nakshatra or lunar mansion) seen in the sky.

Grahas as per Vedic Astrology are: Sun, Moon, Mars, Mercury, Jupiter, Venus, Saturn, Rahu and Ketu.

As per BPHS:

अथ खेटा रविश्चन्द्रो मङ्गलश्च बुधस्तथा।
गुरुः शुक्रः शनी राहुः केतुश्चैते यथाक्रमम्‌॥

Remember, that ‘graha’ are being defined keeping in view their movement in the skies, across the zodiac consisting of constellations, as being observed from earth – i.e. a Geocentric View. The Earth, hence, doesn’t figure in the list of ‘graha’.

Thus, when you observe from earth, the Sun also “appears” to move in the sky across the zodiac, as does the Moon.

The Sun and The Moon, we know, do not fall into the definition of what we know as a ‘planet’, nor do Rahu and Ketu.

What are Rahu and Ketu then?

Rahu (North Node as per Western Astrology) and Ketu (South Node as per Western Astrology) are not physical bodies, but mathematical points on the zodiac, formed at the intersection of the orbit of the Moon and the apparent orbit of the Sun, as observed from the earth.

More about these later as the concept is related to Solar and Lunar Eclipse.