Vedic Sciences As I Understand


I can trace my interest in Vedic sciences to early childhood days in India. At that time, I did not know that what we considered to be a normal daily routine knowledge is actually a piece of Vedic sciences as applied to mundane purposes. I didn’t know then that some of the proverbs that are routinely used in my native language, i.e. Telugu have got a profound spiritual background and astronomical knowledge packed in them. I did not know then that the stories that our grandmother told us were not just simple stories to amuse children, but she was imparting us the knowledge regarding macro and micro-workings of the cosmos.

After obtaining a masters in Engineering and another in Business from the USA and after working in advanced technology (Artificial Intelligence and Machine Learning) for more than a decade, I came full circle to realize that the education that I received at home as a child in India is as or even more valuable than the ones that I received later on. I hope to write articles and share with people about Vedic Sciences, as I am currently learning them in a structured way. These articles will be about this ancient but still continuing and evolving knowledge base as I see them. I will be making connections between what we hear at home and what they actually mean. I am NOT an expert in Vedic sciences and am still a student and will remain so in this life. However, from what I understand, there is a lot of confusion and there are misconceptions about these sciences, some of which I am attempting to address through these articles.

If there are any mistakes here, then they will be mine and not my guru’s. And if any of the readers would like to point me to a more authentic source (that you’ve verified yourself) I’ll be happy to consider and correct/expand the articles as required. Also, if anyone wants me to discuss specific topics, please let me know, I’ll try my level best to gather information about the same and present to the readers.

There are 3 related sciences that interest me; Jyothisha, Ayurveda, and Yoga. All 3 sciences are connected to “Samkhya Philosophy”.

This is the first article in that series. This article falls into the category of Jyothisha.

Science Behind Bizarre Story of “Rahu and Ketu”

One of the most maligned stories in Indian mythology is that of Rahu-Ketu. Maybe because it sounds bizarre, silly and even superstitious. However, this story also happens to be one of those pieces of knowledge that are imparted to laymen in India in an entertaining way, that happens to have solid astronomical and spiritual knowledge behind it. I’ll explain in later articles the probable reason behind the continued use of such stories in Indian civilization.

Here’s the crux of the story or that piece that is of interest for the purpose of this article:

“When Rahu and Ketu, the head and tail of a serpent swallow sun/moon, eclipses happen. Rahu is the head of the serpent, while Ketu is its tail”. They are also known as ‘chaya grahas’.

Side note: Please note that I am not using the English translation of “shadow planets’, to describe Rahu-Ketu, but using the Sanskrit term ‘chaya graha’ as is because the word “PLANET” is a WRONG translation of the Sanskrit word “GRAHA”. There are many such misunderstood Sanskrit words in English that contributed to maligning of our Vedic sciences. In my next article in this series, I’ll explain in a little bit more detail about the difference between ‘planet and graha’ and ‘jyothisha and astrology’.

Side note: Again please note that I prefer to use the term ‘Jyothisha’ as opposed to “Astrology” because they don’t mean the same thing although these two terms are used interchangeably nowadays, ideally, we should know the difference clearly. 

So who/what is Rahu/Ketu? How does he/it catches/swallows Sun/Moon?

First of all, let’s make a note in this article, that this story is explained in the context of Jyothisha which is a combination of Astronomy and Spiritual Sciences and these sciences are complementary to each other and they are not really that separate. There is a common misperception that Jyothisha is used only for predictions. That is not so. Jyothisha’s spiritual purpose is to realize the divine within and understand the purpose of the life of an individual through Karma Siddhantha. Karma philosophy, in turn, has got a cosmic and hence astronomical connection, the interesting details of which will be covered in a series of articles at a later time.

Astronomical Basis of Rahu-Ketu story

Rahu-Ketu story tries to explain how eclipses occur. As per Jyothisha, Rahu and Ketu are two specific mathematical points in the Zodiacal belt.

Side note: ‘What is Zodiacal belt and how it is used in Jyothisha?’ will be explained in later articles.

For the purpose of Rahu-Ketu and eclipses, reference article can be found here:

The summary description given below is based on the article above.

We’re taught that when the Sun, the Moon, and the Earth are in a straight line, the chances are that we may see a lunar or a solar eclipse. Refer to the image below. Note: This is not to scale. 

In the picture above, the yellow path is the ecliptical path. Ecliptical path refers to the sun’s apparent path through the sky as observed from the earth. Refer to the path in blue. That’s the path of the moon’s orbit. Moon moves along its path in the anticlockwise direction. Put your imagination caps on and see the above picture in your mind in 3D. Also, notice that the moon’s orbit is at an angle to the ecliptic plane. So in the above picture moon crosses N1 in the upward direction and N2 in the downward direction. N1 and N2 are the two points where moon’s path crosses sun’s ecliptical plane. In Jyothisha, N1 is called Rahu and N2 is called Ketu. So Rahu and Ketu are the points in the zodiacal belt where eclipses occur and hence as per the Rahu-Ketu story, eclipses occur when Rahu/Ketu swallows Sun/Moon. If you learn Jyothisha, you’ll be taught that Rahu-Ketu are these mathematical points and the calculations around these two points are taught from the astronomical point of view. The mythology side is an analogy and should not be taken literally. 

In addition to that, N1 and N2 actually change their position as the plane of the moon’s orbit does not remain constant and accordingly, it takes around 18.6 years for Rahu and Ketu to come back to that N1 and N2 positions shown above.  (Hence in Jyothisha, it’s mentioned that Rahu and Ketu move wrt earth. Did you know that Rahu-Ketu take about 18.6 years to complete their transit of the Zodiac as per Jyotisha?)

Considering that Jyothisha has got the technique to predict eclipses with good accuracy given such complex phenomenon, we can clearly see that this is just but one example of the astronomical basis of Jyothisha.

Now, naturally, the question becomes, was this knowledge limited to India and Vedic sciences only? The answer is NO. Following and predicting eclipses is something that was done historically by many civilizations like China, Egypy, Babylonia etc., but that knowledge is not in practice today in those civilizations. However, that ancient knowledge regarding astronomy is still in use in India through the continued use of Jyothisha.

Food for thought: Clearly for someone to predict eclipses based on this kind of complex astronomical phenomenon involving Moon, Sun, and Earth, they should have known that it’s the earth that goes around the sun and not vice-versa? Yes. The ancient civilizations knew a good deal about the solar system and beyond. Then why are we taught that Copernicus and Galileo were the first ones to observe that the sun is at the center of the solar system, not earth?  I encourage the readers to research and seek the answer to the above question.

Side note: There are many controversial claims about which is more ancient, Vedic or other knowledge bases? One thing with Indian Vedic knowledge is, for thousands of years Vedic knowledge was imparted to its disciples primarily via oral tradition and through mythology for a number of good reasons. I will cover this historical background as I understand in future articles. For some strange reason, modern educated people are of the opinion that only written history is authentic and the oral history is not. Since Vedic knowledge was not cast in stone literally (i.e. written down) for a long time, it’s difficult to ascertain its ancient roots. But in my opinion, ancientness of a knowledge base should not be the point of its validation. But that’s for some other day. So why the renewed interest in Vedic sciences now? I think it’s primarily because although the similar knowledge existed in other civilizations at that time, unlike other civilizations that succumbed to external invaders forcing their belief systems on the ruled, primarily India (the Indus-Saraswati river based civilization that’s still continuing) managed to save this knowledge despite the continued invasions that took place on her soil also, mainly because of the oral tradition.  So burning the books and closing down Vedic schools did not stop India from saving some of its knowledge bases and passing it onto the next generations. Also, not all books were burnt down either. There is a very important written part was saved not only in India but also in Islamic countries where books on Astronomy, Ayurveda, and Yoga are translated from Sanskrit to their local languages.

Did you know that the famous Nalanda University library was burnt down along with millions of manuscripts including those of Ayurveda, Yoga, and Jyothisha by an external invader in 1193 AD? The university was attacked multiple times and teachers and the scholars were murdered to destroy this knowledge base. Did you also know that such attacks have happened on other civilizations also, not just Indus-Saraswati region?

Spiritual Basis of Rahu-Ketu Story

This requires an introduction to the spiritual side of Jyothisha and how that connects with observable cosmos. This will be covered in my next article. Here it is. Click on this link.


  1. Ecliptical plane: NASA website

  1. Naked Eye Astronomy: BBC website

India’s ancient university returns to life: BBC website

#VedicSciences #Jyothisha #Ketu #Rahu #Astrology