Question

What was the circumference of the Earth calculated by Aryabhatta?
A. 24901 miles
B. 24835 miles
C. 22134 miles
D. 24234 miles

Answer 1

Hint:
> The dimensions and shape of the Earth was discussed in the 4th chapter of his book, the Aryabhatiya.
> He concluded this data by studying the position of the sun and the moon in the same latitude at different times.

Complete answer:
According to Aryabhatta’s calculations, the circumference of the Earth was 24835 miles.
Aryabhatta was an Indian mathematician and astronomer. He was born in 476 CE and was a native of Kasumapura, which is present day Patna, Bihar. He is known to have introduced the place-value system in mathematics and the concept of zero (though he did not use the symbol ‘0’).

His notable works include Aryabhatiya and Arya Siddhanta:

Aryabhatiya – is his most famous work and it contains four chapters on mathematics and astronomy. The first chapter includes units of time, trigonometric function, and planetary revolutions. The second chapter includes mensuration, progressions and different types of equations. The third chapter includes methods for determining the position of planets and calculation regarding the intercalary months. The last chapter includes mathematical aspects of celestial spheres, causes of day and night, movements and measurements of earth and zodiac signs.

It is from this text that we know about Aryabhata determining the exact circumference of the earth to be 24835 miles. It is assumed that he was able to do this by identifying two locations on the same latitude using a gnomon and then proceeding to calculate the difference in time, by observing the position of the moon.

Arya Siddharta – is a lost text, and the second known text of Aryabhata. Through the writings of one of Aryabhata’s contemporaries we know that it comprised his works on astronomical computations. It contained descriptions of all the astronomical instruments that he used.

Therefore, the correct answer is B

Note:
> Since Aryabhata has been one of the most influential people in Indian history, the first Indian satellite was named Aryabhata in his honour.
> Even a crater on the moon has been named Aryabhata.
> The Aryabhatta Research Institute of Observational Sciences was established in Nainital and named in his honor. It is an institute for research in the field of astronomy and astrophysics.