text: how long is a god day? could one god day be 2.6 billion years long or only 24 hours? how do you know for sure? how long is a god day? how many days did it take to make the universe? could a god day be longer than 24 hours? how can anyone tell for sure? the bible does not give the length of a god day as 24 hours. so how do christians think they know for sure? could a god day be 2.6 billion years? or could one day for god be 100 million years. how can anyone say for sure without using faith as an easy excuse for knowing for sure because no where in the bible does it say that a god day is 24 hours? a "creation" day can last an indefinite time span. there are several examples in the bible about how "day" can have the connotation of a period of time that is not necessarily 24 hrs. for example, genesis says that on the seventh day of creation god came to rest and in relation to this the apostle paul mentions in one of his letters that "we are still living in the resting day of god". so that last "day" of creation, the seventh day, streches up to our days.