Physical Review A, B, C, D, E and Physical Review Letters require that articles be dropped from the start of titles. Maybe some other journals do as well.
I have never heard of anybody requiring that a, an, the be dropped at the start of an abstract. A brief glance at Physical Review Letters shows that a reasonable fraction of their abstracts start with an article. But maybe the requirement to drop the article from titles was the inspiration for your adviser's remark.
Titles in English generally use an abbreviated grammar that shortens them. However, most newspapers and publications don't actually forbid articles at the start of titles. This requirement in Physical Review is somewhat controversial, and leads to a few titles having unusual English grammar1.
Since this is your adviser's suggestion, and since that sentence sounds perfectly fine without the article, I would suggest going ahead and dropping it.
1 For example, a title starting with "General Theory of Relativity ..." or "Moon was created ..." would sound wrong.