Who discovered Zero? It is generally believed that Aryabhatta discovered Zero. But truly speaking, he did not. It is a wrong information that has been spread during the course of time for reasons unknown. One may ask how we can say that. It is because in the treatises written by him which is available today, there is no mention of discovery of Zero. Who then discovered Zero?
When we talk about discovery of Zero, we need to think what type of Zero are we referring to. For a layman, he would not be thinking beyond the meaning of Zero as ‘nothing’. But Zero degree Celsius doesn’t mean there is no temperature. Here, Zero is a place holder between positive and negative numbers. This notion of Zero must have come while negative numbers were first discussed by Brahmagupta (7th century Indian Mathematician) who was the first one to discuss about rules for operations with negative integers (12 centuries before the West started discussing about negative integers).
The Babylonians and Greeks had some notion of Zero but that was not the kind of Zero that we use today (refer the two links given at the end of this article). It was Pingala (300 BCE) the author of Chandass Shastra (one of the 6 Vedangas) who used Zero as a symbol for the first time in History. Pingala was also the originator of Binary Mathematics (Ref: ‘History of Mathematics in India from Vedic Period to Modern Times‘ online course on NPTEL, lecture on Pingala by Prof. M.D.Srinivas, Institute of Policy Studies). Pingala also dealt with Permutations and Combinations (2 millenniums before it was discussed in the West). It is very clear that for discussing such areas of Mathematics the knowledge of Zero is very important.
In other civilisations during the period of Pingala, Mathematics was not that advanced and they could manage without Zero. In fact, due to the lack of knowledge of Zero, they lagged behind in Mathematics.
So who discovered Zero? The answer is ‘we don’t know’. Looking at the kind of Mathematics that was dealt in India during the BCE period, it can be said that the use of Zero as not just a symbol, but as place holder and a symbol for nothing should have happened in India. But as Indians weren’t interested in accrediting their names to discoveries, it is not known who discovered Zero. As a matter of historical evidence, all that can be said is that it is in Pingala’s Chandass Shastra that we find the appearance of Zero as a symbol (as a digit) for the first time. In other civilisations, till that time zero was used only for absence of something. The development of decimal place value system should have developed somewhere between the period of Pingala (300 BCE) and Aryabhatta -1 (5th Cent CE) because by the time of Aryabhatta the decimal place value system was very much in use.
(Some interesting reads can be http://yaleglobal.yale.edu/about/zero.jsp
NPTEL Course on History of Indian Mathematics https://www.youtube.com/watch?v=p2WankcGP3Q&list=PLbMVogVj5nJThf31TNSQzuN7zqxe7HdRN)