Surya Siddhanta in English rhyme

Ancient Mathematical Astronomy

Notable Observations and Calculations
Tropical Year: Estimated at 365.2421756 days, which is remarkably close to modern scientific measurements.
Sine Tables: Contains one of the world's earliest known tables for the sine function, calculated for every 3.75 degree of arc.
Planetary Motion: Describes the eastward motion of planets and provides orbital parameters based on the number of revolutions per Mahayuga.
Spherical Earth: Describes the Earth as a sphere (Bhu-gol) and discusses gravity long before modern European theories.

The wheel of time begins its ancient spin,
Where four great ages let the cycle in;
A Mahayuga marks this cosmic climb,
With 4,320,000 years of earthly time.
The Satya Yuga stands in golden light,
Four parts of virtue, pure and shining bright;
Then Treta follows with a three-part grace,
As silver shadows touch the human race.
In Dvapara, the balance starts to sway,
With only two parts left to lead the way;
The copper age gives way to iron's breath,
Where Kali Yuga brings its spiritual death.
By four-three-two-one ratio, they descend,
As truth and years both hasten toward the end;
But when the darkness of the fourth is through,
The golden morning starts the world anew.