From Hanuman Chalisa:

From Hanuman Chalisa:

युग सहस्र योजन पर भानू ।
लील्यो ताहि मधुर फल जानू ॥
Yuga Sahasra Yojana Para Bhaanuu |
Liilyo Taahi Madhura Phala Jaanuu ||
 
 
Meaning:
The Sun which was at a distance of 1000 yug yojan away,
You Swallowed It (the Sun) thinking it to be a Sweet Fruit.
 
युग(12000) *  सहस्र(1000) *  योजन(8 mile ) = 9,60,00,000 mile
9,60,00,000 mile * 1.6 = 15,36,00,00 k.m. = distance from earth to sun.
http://www.universetoday.com/14437/how-far-is-earth-from-the-sun/
 
 
 
Speed of light from veda.
 
तथा च स्मर्यते योजनानां सहस्त्रं द्वे द्वे शते द्वे च योजने एकेन निमिषार्धेन क्रममाण नमोऽस्तुते॥
 
"tatha ca smaryate yojananam. sahasre dve dve sate dve ca yojane ekena nimishardhena kramaman"
 
Meaning:
 
"With deep respect, I bow to the sun, who travels 2,202 yojanas in half a nimesha."
 
http://en.wikipedia.org/wiki/Speed_of_light
 
 
Note:
Half a nimesha is 0.12 seconds
yojanas = 8 to 9 miles.
http://www.universetoday.com/14437/how-far-is-earth-from-the-sun/