Srimathe Ramanujaya Namaha,
Copy pasting Kongil Piratti Swami’s explanation from the above thread as pointed out by Srinivasan Swami.
The best way to explain is as below. Adiyen will use Sri Velukkudi Swami as an example.
Consider Sri Velukkudi Swami as Chandran Deva.
Swami reside in HIS ThiruMalaigai (Home) which is Chandra Lokam.
Swami’s Home (Chandra Lokam) is inside the bigger city Thiruvellikeni (which is Suvar Lokam).
But, Swami (Chandra Deva) travels all around India and outside India (basically Orbiting) “inside and away” from his residence Home (Chandra lokam) as well as “inside and away” from HIS city Thiruvellikenei (Suvar Lokam)
Same way with Suryan that we see, Surya deva residence is Bhuvar lokam, but He orbits in His chariot.
During which, Chandran Deva orbit & Suryan Deva orbit overlap in Bhoomi’s path in Bhoolokam, which causes the Grahanam (Solar or Lunar eclipses) accordingly, but their own Lokams (residence) are independent and far away from Bhoolokam. Aidyen believe, the explanation should make it clear. Let’s keep Sri Velukkudi Swami’s ThiruvAdi on our Head and try to visualize in our mind.
Some study during mechanical engineering about engineering drawings.
In which there is Isometric view of an object and then side view, top view, bottom view.
The isometric view is the 3D view & all other top/side/bottom views are 2D planar views.
So, an original object is always in 3D space, and if we see the same 3D view in a 2D plane, it appears as a projection. Please see the below adiyen hand sketch.
Like, if we a bus from a 2nd floor building, we can see the bus topside, front side and the side view all together. This is isometric view of a bus. Same bus, if we stand infront of it, we can see only front side, which is the front view (2D planar view). That doesn’t mean, we can conclude bus is a square as seen in in one plane (front view). It is actually 3 dimensional as seen in isometric view.
We can easliy relate this. At times, the moon is full circle but is very big, and sometimes the same moon is full circle but appears as smaller size.
This is because, when the moon is travelling towards the Suvar lokam (farther away from Earth), the full circle size of the moon is smaller.
Same way, when the moon is travelling closer to the Earth, the full circle size of the moon is bigger. Also Moon size is bigger than Sun size as per Simadh BhagavAtam.
Also the simsumara Chakkaram shows the each Devas in the form of the planets. It is just an arrow showing where they are in TOP view, but in Isometric view, their orbits are far away.
Please see the Isometric (3D view) and the Top view (2D view) of adiyen hand sketch illustration
Adiyen ElayaAlwar Srinivasa DhoddayAcharyar Dasan