Length of day in Genesis
Question
Can the Hebrew word "yom" be used to describe a period of time defined by the cycle of evening and morning, rather than a fixed 24-hour period? In Genesis 1, the phrase "and there was evening, and there was morning, the first day" (Genesis 1:5) suggests a cycle of light and darkness, rather than a specific time frame. Do you agree it's possible to interpret "yom" as a period of time that's defined by the earth's rotation, regardless of its length? If the earth's rotation was slower, a "day" could indeed be millions or billions of years long. The biblical account doesn't specify the length of the days, so it's possible to consider this interpretation in my opinion. There was no sun initially but another light source as you know so that's the context.
Answer
Shalom!
Thank you for your question.
Yes, there are commentators who write as you have described.