I read an science article once, where the scientist said that, although the universe is so perfect, there couldn't be a creator, because that program or computer would have to be unimaginably large.
Another time, an atheist scientist said, yes, the design is perfect, however if there is a God, why would the God who created the universe and all creations so perfectly, want to pay attention to what a single person like us, do or feel? He would be too busy with the other larger creations.
As can be seen from both of the above arguments - the root of the disbelief is that, they cannot imagine that there could be a God so great that could and would be able to do ALL of that - even though they acknowledged and found that the creations were superior and perfect.
Why they find it hard to accept, is probably because they have been brought up with an image of a god. A visual image - and that image is of a man (whether it's an old man or a young man - or in some other religions - an animal. Astaghfirullaah.
That is the big issue now. If that is the image of God that they have, of course then cannot imagine that that mere man or animal that they perceive - would be able to create an ever expanding universe.
God have said that he is UNLIKE any of His creations - and these people did not know this. God is the Greatest. And when we say greatest - it is beyond your perception and imagination. We cannot accommodate the knowledge of God.
Even if all the oceans on the earth is ink, and all the trees on this planet are made into pens - it would never be able to write God's knowledge, even if the supplies are increased seven fold.
Man only need to realise, the superiority of the Creator through observing and studying His Creations to understand that God is Great. God has left a book, fit for human and jin to learn and understand - and guide us on how to live and what to believe. God has given us evidences.
If you would just be less arrogant, you would realise and accept that you cannot encompass God's knowledge - and as such submit to God, as one of his Creations and we are at the mercy of the Loving God.
When we accept that, and learn what He wants to teach us, our lives will be more manageable and peaceful, insyaaAllaah.
So scientists, they have to be sincere and honest about their feelings, and be humble. It is more logical to believe that there IS a Creator, a perfect Designer, than to believe otherwise. Relent, and submit.