If we look back at our ancient texts we realize that a lot was known by our ancestors that we somehow have forgotten and when these things are rediscovered we tend to believe that a new discovery has happened. One such thing is the distance between the Sun and the Earth.
What is the distance of Sun from Earth & Who discovered the Astronomical Unit
The distance between the Sun and the Earth is 1.49 million kilometres. The orbit of earth around the sun being elliptical the distance actually varies at different points by 3% and the average of these values is considered as the distance which is known as an Astronomical unit. In 1653 Christiaan Huygens calculated the distance between the Sun and the Earth. With due respect to his discovery he has also explained how he calculated this using the phases of Venus to find the angles in a Venus-Earth-Sun triangle.
Is this a new discovery ?
Above I have mentioned what is widely known and now I will mention something that is not known. 16th century Indian spiritual poet Tulsidas (1532-1623) has written a devotional hymn address to Lord Hanuman known as Hanuman Chalisa. The exact date of writing of Hanuman Chalisa is not known but it could be easily concluded that it was written before 1623. Along with Ramcharitmanas, Hanuman Chalisa were written by him inspired by Valmiki’s Ramayan which was written in 3rd century BCE. Now the question is how Hanuman Chalisa is related to this complex calculation of Astronomical Unit.
Hanuman Chalisa, Valmiki’s Ramayan and many other ancient religious texts of Hinduism depicts a story about Lord Hanuman that when he was a child he thought of the Sun as a tasty fruit and went on to eat it. Lets see what is written about this incident in verse 18 of Hanuman Chalisa.
जुग सहस्त्र जोजन पर भानू। लील्यो ताहि मधुर फल जानू।।
Jug sahastra jojan par bhanu | Leelyo tahi madhur fal janu ||
The meaning of this verse is Bhanu which means Sun is lying at a distance of Jug sahastra jojan and Hanuman dashed upon it thinking it to be a sweet fruit. Being in Awadhi language Yug and Yojan are written as Jug and Jojan which means the same.
Now lets get to the calculations. 1 Jug(Yug) is a timespan of 12000 years and it is very common in ancient texts to use it as a unit to denote the figure 12000 . Sahastra is a Sanskrti word used to denote 1000. Jojan(or Yojan) is a unit of distance equal to 8 miles. Now,
Jug Sahastra Jojan
12000 * 1000 * 8 = 9,60,00,000 miles
Since 1 mile = 1.6 kms
9,60,00,000 * 1.6 = 15,36,00,000 kms or 153 million kms. Now the distance of Sun from Earth during aphelion i.e., when the Sun is farthest is 152 million kms approx.
Another notable thing is that Tuslsidas was no scientist but a poet and nowhere had he mentioned how he derived this distance. Calculations or whole descriptions of anything are mentioned mostly when the discovery is new. When something is widely known these thing are not mentioned. Now the Valmiki’s Ramayan which dates back to 3rd century BCE also mentions this incidents and these stories about Lord Hanuman are way older than this. But we can easily conclude that the distance between the Sun and the Earth is widely known to Indians years ago. The question here arrives how we lost our great knowledge about astronomy. We can hope all this can be unearthed soon but as of now there are a lot of scientific discoveries that can be found when we go through our ancient sacred texts.