Occasionally people pooh pooh the Genesis account of creation by saying that modern science proves that the earth could not have been created in seven days.
By which, of course, they mean seven normal days on earth. Even if that is what is meant, that assumes that days on earth are all the same; and they are not.
Putting aside any minor variations, the earth’s rotation is slowing. So a day now is longer than a day a thousand years ago.
And of course, if we go back millions of years then the change in the length of a ‘day’ is measured in hours! And so on, so a day is not a constant.
In fact, if one goes all the way back to the creation of the earth and the cosmos, as Genesis does, the length of a day becomes essentially meaningless except to simply imply some passage of time. And instead of that time measuring how long it took for these events to occur, the events themselves become the measure of time.
So, as another part of the bible puts it, ‘With the Lord a day is like a thousand years, and a thousand years are like a day’.