Does Rahu cover the sun to cause eclipses?
You say that Rahu covers the sun, covers and heats up the sun and this is the cause of the eclipse.
How do we perceive this? The Bhagavatam describes not that Rahu consumes the sun but that it covers the sun. Now here we have to understand that there can be explanations which are parallel and they are complementary not necessarily contradictory. So I won't go into again technicalities but just simply speaking if you look at Jyotish Shastra they do give orbits and they give positions because Jyotish Shastra also if you know it makes predictions.
If you take a panchang from your local priest he can tell you okay the next solar eclipse is going to come at this time, the next lunar eclipse is going to come at this time and they also predict with a fair level of accuracy. So eclipses have been predicted not just since modern science came up but not just in the Indian tradition but various other places also because there was an understanding of the significance of celestial phenomena like this. They were predicted.
So the first point is using Jyotish Shastra model also eclipses were predicted and they were predicted with a fair degree of accuracy because eclipses are times which are considered to be somewhat inauspicious. So at that time people are supposed to do more pure activities and avoid impure activities and people were told in advance because this is the time when eclipse would come. So if the model was simply just a myth, the idea is just mythological.
How can you have some demon coming and consuming the sun? So there is a simplistic caricature of the traditional understanding but it was just simply a mythology. How could some mythological imagination predict something with reasonable precision? The prediction was because there are orbits described and if you look at Jyotish Shastra, it is described that Rahu and Ketu they are also celestial objects. Just as we have sun, moon, these are celestial objects.
So Rahu and Ketu are also celestial objects but they are celestial objects of a different nature. It is like you say today in science when we talk about black holes. Now black holes you cannot actually perceive their existence directly because whatever light goes in the black hole, it is just suckering.
So if there is a black hole over here, we cannot directly have a picture of the black hole although we may be shown pictures in our books but those are not reflection of what is actually seen. They are just diagrammatic depictions of what is inferred based on observations. What happens is if there is a black hole somewhere and the light that is going towards the black hole that is consumed but the light that is going nearby, its path twists and when the path twists, these two are twisting, there is a black hole over here.
So just a black hole is inferable in that way. But science also talks about dark matter which is by definition itself not perceivable. It says dark matter, the only way they infer it exists is because that is required to balance the gravity force of the universe.
So they infer that it must exist. Similarly, Rahu and Ketu are posited as planets made of subtle matter which is not perceivable to us humans. Now Rahu and Ketu, they are planets and they have presiding deities.
So there is a being called Rahu who is demoniac and he is the presiding deity of the place called Rahu. It is like Suryadev is in charge of Surya. So like that Rahu is a person who is in charge of Rahu, the celestial object.
And this celestial object has a trajectory, a path, has an orbit and its orbit is such that whenever the sun, moon and earth are in one line at that time Rahu also comes over there. So using the prediction of Rahu's position, eclipses can be predicted or using, as the modern science does, using the linearity of the earth, moon and sun, eclipses can be predicted. These two are different models and they are not contradictory, they are complementary.
One focuses on simply the physical objects and how the physical objects have physical effects. And the usage of Rahu and Ketu as explanations for the cause of eclipses that focuses on another factor. Okay, the earth, sun and moon come in a line.
Why do they come in a line? We may say their orbits are like that and their orbits bring them in that line. But why are things arranged in such a way that they come in a line like that? That is because there are higher factors, that is because there are higher beings governing the whole cosmos and that higher governance is conveyed by the point of Rahu and Ketu coming in. So both these explanations of the sun, moon and the earth linearity as well as Rahu and Ketu coming in, they are complementary, they are not contradictory.