Will scientists find the purpose of existence in future through science ?

In case you're interested in my opinion, I would say no. I think that such deep matters as existence and non-existence are beyond our capacity to imagine. In the end we will see, but probably not much before then. Or is it the beginning? Try to believe in a new beginning.

I think Jean Paul Sartre was probably on to something in his work "Being And Nothingness." I, for example, happen to be an extremely right wing Roman Catholic and even work for several Roman Catholic publications, but even I must admit that all theology fails to adequately dispute what Kant called "the great scandal of philosophy," which of course is a reference to Descartes' revelation that the only thing we can know with absolute certainty is that we exist at minimum of at least a being that is experiencing SOMETHING. What that is in any kind of ultimate reality is very much a mystery that is most probably unattainable even in death. What I like about Sartre is that in whatever existence we are within, we have this ability to make choices...indeed we are "CONDEMNED TO BE FREE!!" as Sartre brilliantly puts it. I would say, theology aside, this is the closest that we can ever come to a greater reality and any kind of legitimate understanding of the purpose of this life we find ourselves in. In other words, all we can know is that we are some kind of free being that experiences something rooted in a fairly solipsistic environment....hence, the very basis of the question, "What is the meaning of this existence?," is unfortunately rooted in the answer to the question.....which is basically, this existence is whatever you want to make of it. ....but I could be wrong.