Let’s talk about the Facts first and opinion later.
FACTS about gravity
- Newton(1642 -1726/27) gave the theory of gravity around 1700s
- Vaisheshika darshan is at least 2300 years old(according to western claims), much older according to Indian traditional claims.
- Establishing of Jesuit missions in India between 1500 – 1800, the most famous among them was Madurai mission which established colleges and started translations.
FACTS about calculus
- Bhāskara II (c. 1114–1185), had started working with basic calculus
- Mādhava of Sangamagrāma (1340 – 1425) took it further and worked with many infinite series.
- Newton & Leibnitz discovered calculus in 17th century
Gravity may have been independently discovered by Newton but Indians knew about it much earlier than Newton. Surely, Newton was a beneficiary of all the translation works by Jesuit missionaries in India.
After establishing these facts, now we can offer some opinion that it takes a long tradition of knowledge to discover things which are very complex. The number system of Brahmagupta reached Europe only in 13th century.
But Christian Europe took about 300 years to accept it. Now how can anyone start working with calculus without clear understanding of numerical system? These are some of the questions to be answered.
Mr C.K Raju has done a lot of research in this area. So you must refer to some of his talks or books.