This "everything in science was developed by man" comment is a little confusing. It sounds like you are suggesting that man invented the speed of light. We observe what happens around us and we make conclusions based on those observations. We call this process "science" but the speed of light is not based on our ability to "develop" a process by which we can measure it. The speed of light, as we are able to observe it, was created by God. It's the same with things like magnetism and gravity. We can observe and test these things; we can manipulate them and yes, develop them for our benefit, but God still created them.
Perhaps there really is some mystery which is yet to be discovered about the speed of light; some difference of perspective from our normal view of how light should work. But if that is true for our understanding of light, can't it also be true for our understanding of the creation story?
Perhaps there is something more to what is being described than a literal 24 hour day (I'm not opposed to a literal 7 day interpretation, but just exploring possibilities). I mean, the story talks about "evening and morning" to mark the days, but the sun wasn't even created until the fourth day. How can there be an evening and a morning without the sun? Though I suppose it's the rotation of the earth which marks a full day so we could still have a full 24 hour day even without the sun, but the words "evening" and "morning" only have meaning in the context of sun rise and sun set.
The story also says God divided the light from the dark and called the light "day" on the first day but again the sun wasn't created until 4 days later. I'm not questioning the order of events, but when examining the actual words there is a fair bit of reason to consider that "evening and morning were the first day" could easily have other interpretations besides a literal 24 hour day as we recognize it now.