Modern science cannot answer every question we care to ask, regardless of how important it is. Another option is to make up an answer and put a lot of scientific jargon around to make it sound like it's all scientific and everything.

Science can help us understand how morality develops in human; potentially how evolution enabled morality to emerge in our ancestors. It even has the potential to help us clarify what we collectively consider morality.

But science is never going to tell us what is right and what is wrong. Most people believe in objective or at least common reality. People who don't believe in objective reality are either insane or they are very poor thinkers. Else we would have a lot of conversations like the following:
"You punched me in the nose."
"No I didn't."
"Yes, you did, I saw you."
"That was *your* reality. In *my* reality, I handed you a million dollars."
And so forth.

This is a recognition of objective physical reality. But we are not satisfied with this. We want to believe in objective moral reality. We want to believe that there is something that tells us what is right and wrong that exists beyond just us. We desperately want to believe that "we matter" and that the universe or something greater than us notices us, even cares about us.