One of the “scientific mistakes” which people who argue against ancient Indian science point to is that, ancient Indian astronomers “wrongly” classified Sun and Moon as Planets, and did not include Uranus and Neptune in their list of 9 planets.
The very first common sensual mistake here is to assume that the definition of Graha is the same as that of modern planets. This was assumed just because there were 9 Planets and there are 9 Grahas. Now let us see the actual definition of each of these.
Definition of a Planet
Planet is defined as an astronomical body in the solar system that moves around or orbits the Sun.
Definition of a Graha
The Sanskrit word Graha is derived from the root verb ग्रह् which has 25 meanings. When referring to astronomical bodies, the word Graha means, the one that “holds or captures”.
In other words, Graha is an astronomical body which plays a significant role in protecting or holding the life on Earth.
Did you see the difference? Unlike the definition of a planet, whose primary attribute is “motion around the Sun”, Graha has a primary attribute of being “influencing life on Earth”.
Graha – The one that influences
What is so special about these Grahas? These are the significantly large neighbors of Earth in our Solar System who play a major role on the life on Earth.
The Sun gives us energy and keeps Earth in a stable orbit around it, the moon generates tidal force on Earth’s oceans. In the outer zone we have Jupiter and Saturn that shield the life on Earth from most of the incoming comets and asteroids and other giant rocks by attracting them by their huge gravity, without which life on Earth would have never survived. Remember, how just one rock that missed the influence of Jupiter ended up wiping out Dinosaurs!!
Then we have our immediate neighbors (Mars, Venus, Mercury) that have played a major role during the early days of planet formation ensuring that Earth remains in the habitable zone of the solar system. Earth is at the right distance from Sun which makes it neither too hot (vaporizing all water) nor too cold (freezing up all the water). Without these planets Earth probably would have ended up outside the habitable zone, and there would have been no life on Earth!
Weekdays and Grahas
Did you know? The seven days of the week are named after the first seven grahas in the same order as mentioned in the Sanskrit hymn Navagraha Stotra below
Om Namah Suryaya (Sun/Sunday) Chandraya (Moon/Monday) Mangalaaya (Mars/Tuesday) Budhaayacha (Mercury/Wednesday) Guru (Jupiter/Thursday) Shukra (Venus/Friday) Shani(Saturn/Saturday) Bhyashcha Rahuve Ketuve Namaha
The oldest reference to a seven day week can be found in the ancient Sanskrit text Gargi Samhita.
What about Rahu and Ketu?
The other argument made against Grahas is that, two of the grahas – Rahu and Ketu, do not exist at all!
Well yes, where have they claimed that Rahu and Ketu can be “seen”. Rahu and Ketu are actually classified as Chaaya Graha (meaning shadow grahas, not the real ones). Rahu and Ketu are actually the points of intersection of the paths of the Sun and the Moon as they travel in the celestial sphere. Rahu is the north lunar node and Ketu is the south lunar node.
It is also a well known fact that eclipses occur when Sun and Moon are at one of these lunar nodes (Rahu or Ketu). Hence you have this story in India about Rahu swallowing the Sun.
Rahu and Ketu are included in the list of Grahas, even though they don’t have any physical presence in the sky. This is because, these lunar nodes, by causing eclipses, exert a different kind of influence on life on Earth. The term Chaaya (“Shadow”) is used to describe Rahu and Ketu because moving into their shadow (position) causes eclipses of Sun and Moon.
The common phrase used in Indian languages, “why are you sitting as if Rahu has caught you” while referring to people looking blank, is because even the Sun goes blank when Rahu catches (influences) it.
Why no Uranus and Neptune ?
Most probably because they are not visible to the naked eye in the night sky. Or probably because they do not have any significant role in influencing or preserving the life on Earth.
Why no Earth ?
As you can see now, Earth is a planet, but not a Graha. Because Graha is an astronomical body that “influences” Earth, so Earth itself cannot be a Graha.
What about Pluto? Sorry, not a Planet anymore.
Coming back to modern astronomy, for those who are unaware, the number of planets today is not 9, but 8. Pluto was removed from the list of planets in 2006, and a new definition has been given to planets today which only applies to the solar system. According to this definition a planet in its orbit around the sun should also have cleared its orbits of any competing bodies for the orbit. Now since Pluto keeps crossing into Neptune’s orbit every now and then, and is dictated by Neptune’s gravity, Pluto is no longer classified as a Planet.
So while all these days modern astronomy taught us that there are nine planets in the solar system, today we are being told that there are only 8! The 9th one was a mistake.
Ok fine, but by the new definition of “clearing the neighborhood”, shouldn’t even Neptune be removed from the list of Planets? After all Pluto keeps crossing over into Neptune’s orbit every now and then. Neptune might be controlling Pluto’s orbit, but it definitely hasn’t cleared Pluto out of its neighborhood isn’t it?
We still have 9 Grahas and a consistent definition even after thousands of years, while planets have ranged from 7 Planets to 8 Planets to 9 Planets and back to 8 Planets now in just past 2-3 centuries ;)