Description of distance
The description of the distance is propounded here as mentioned in the Bhaagavata Cosmology- A Vedic Alternative to Modern Cosmology by Pavaneshwar Das.
Saint Srila Vaadiraja Tiirtha swami, a master of Vedic mathematics, gives the divisions and calculations of "Yojana".
7 Sarsapas (mustard seeds) - 1 Vrhi (length of a paddy seed)
3 Vrhis - 1 Angula (inch)
24 Angulas - 1 Hasta or 1 cubit (= 2 feet)
4 Hastas - 1 Danda, staff length (= 8 feet = 96 inches)
1000 Dandas - 1 Krosa (= 4000 hastas = 8000 feet or 96,000 inches)
4 Krosas - 1 Yojana (= 32000 feet or 16,000 hastas or 384,000 inches)
Considering 1 mile = 5278.87 feet or 1609 meters
1 Yojana = 6.06 miles (= 32000 feet/ 5278.87 feet) approximately
Thus the scholars of Madhava accept 6.06 miles per Yojana for all calculations referred to in the book "Bhugola Varnanam". Srila Prabhupada and many other acharyas used 8 miles per Yojana for all calculations in Srimad-Bhaagavatam. In the biography of Sreepada Sreevallabha, 10 miles per Yojana was depicted. The Madhva scholars reconcile this as below.
The fact that seeds and like were bigger in the previous ages and as time progresses their sizes are reduced as indicated in SB 12.2.1. For the same reason, a man's cubit or Hasta measured 24 inches then as against 18 inches now obtained. Consequently, the average height of man in those days was 8 feet, of course, leaving margin for abnormalities. Incidentally, we may note that Acharya Sri Madhava is described as a personality of 8 feet in height and everyone could have darsan (or cite) of the bust of that personality as he moved in the midst of crowds in procession. By reconsidering the above change in Hasta (cubit) measurements, 1 Yojana will be:
1 Yojana = 16000 Hastas x 24/18 =21333.333 Hastas = 42,666.667 feet
Considering 1 mile = 5278.87 feet or 1609 meters
1 Yojana = 8.08 miles (= 42,666.667 feet / 5278.87 feet) or 8 miles (approximately).
Richard L. Thompson (Sadaputa das) mentions in his book 'Vedic Cosmography and Astronomy' about the calculation of Yojana. One standard definition of a yojana is as follows "one yojana equals four krosas, where a krosa is the maximum distance over which a healthy man can shout and be heard by someone with good hearing." It is difficult to pin down this latter figure precisely, but it surely could not be much over 2 miles.
1 krosa = 2 miles
1 yojana = 4 krosas = 8 miles
Another definition is that a yojana equals 8000 nr, or heights of a man. Using 8 miles per yojana and 5280 feet per mile, we obtain 5.28 feet for the height of a man, which is not unreasonable.
1 yojana = 8000 nr or heights of a man
1 yojana = 8 miles = 8 x 5280 feet per mile = 42,240 feet
Height of a man = 5.28 feet
To justify these reductions in scale, Vamsidhara observes that the yojana is defined on the basis of the human body. Thus a yojana is 16,000 hastas or cubits (sometimes mentioned as 32,000 hastas), and a hasta is 24 finger-widths. Also, a hasta can be defined as one-fifth the height of a man standing with his arms stretched up. As the bodies of infants, children, and adults vary greatly in size, so the yojana also varies, and in this way one can explain differences between various estimates of distance.
Acharya Sri Vamsidhara in his commentary to SB 5.16.7 quoting Siva Purana gives divisions and calculations of a yojana.
1 Tryanuka = 6 Atoms
1 Vaalaagra = 8 Tryanukas
1 Liksaa = 8 Vaalaagra
1 Yuka = 8 Liksaas
1 Yava (Anguli) = 8 Yukas
1 Taala = 8 Yava (Anguli)
1 Hasta = 2 Taala (16 Angulis)
1 Danda = 4 Hastas
1 Krosa = 2000 Dandas (app 2 miles)
1 Yojana = 4 Krosas (8000 Dandas; 32000 Hastas; 512000 Angulis; 8.0825 miles)
Considering 1 mile = 1.609 km = 5278.8714 feet = 63,346.457 Angulis/ Inches
1MY: 1 Million Yojana (10 lakh yojanas)
1 AU: 1 Astronomical Unit, which is the radial distance between the earth globe and the sun, which is approximately equal to 150 million kilometers.
interestingly Hanuman Chalisa, written by Goswami Tulsidas in the 15th century, gives the distance between sun and the earth. This has been calculated much more accurately than the 17th-century scientists even before 2 centuries. Here's a portion of Hanuman Chalisa, a two-line prayer, computes this distance with great simplicity.
tumharo mantra vibhishana maana, lankeshwara bhaya saba jaga jaana
juga sahastra yojana par bhaanu, lilyo taahi madhura phala jaanu
This means that the sun (bhaanu) is at a distance of "juga sahastra yojana." According to traditional conversation practices that are in use as per Vedic Literature this comes to,
1 Juga = 12000 demigod years
1 Sahastra = 1000
1 Yojana = 8 miles
Thus juga sahastra yojana = 12000 x 1000 x 8 = 96,000,000 miles, where 1 mile = 1.6 km
This further implies that the distance is 96,000,000 x 1.6 km = 153,600,000 km (app 1 AU)
Ref: Bhaagavata Cosmology- Vedic Alternative to Modern Cosmology by Pavaneshwar Das