Young Earth, Old Earth

Was reading Genesis 1 and found it really interesting how God created the universe; especially how God created light on the first day, and there was evening and morning. But the sun was not created until the fourth day.

Of course, this is key to understanding there is no necessity for the universe to be created in six 24-hour days. A day as defined the dictionary is the time between two sunsets or sunrises. However, since the light created on the first day was not the sun, we have to use a more general definition: e.g. the time period between two mornings. This is the definition used in the bible in Genesis 1:5b: And there was evening, and there was morning —the first day. This is perfectly consistent with how we use the word "day." For example, a day on Mars is 24 hours, 37 minutes and 35 seconds. Not 24 hours.

So the length of time between the first morning and the next in Genesis 1 can really be any period of time. It naturally follows that the length of time for the subsequent six days are the same.

This is important because Christians need to know that they are not obligated to believe the earth is 7000 years old. The bible simply does not say how old the universe is, nor how long creation took.