I read 2 Peter in the context of people who were expecting an immediate eschatological fulfillment of Jesus’ promise to return and vindicate them. They thought it was imminent, but tomorrow kept coming and Jesus did not return and this was a big deal. Jesus had said some of them would not taste death before seeing Jesus come into his Kingdom and they were wondering what was up. People were dying off. There was persecution and bad stuff and they wanted to know why Jesus was taking so long.
So Peter is reminding them that even though they are living in “the last days” that doesn’t necessarily mean that God is on our timetable, and it might be a while, because one day is like a thousand years to God. I think the point of 2 Peter 3:8 is to encourage them not to lose heart in the face of persecution or lose hope in the promised Resurrection even though they had already waited much longer than they thought they were going to have to wait. I don’t think it’s a divine equation to help us calculate the age of the earth from Genesis.
With the Psalm reference you give, I think it is just an expression of praise for God’s greatness in comparison with humans. Unlike humans, whose fleeting lives come and go like grass or flowers or dreams, God is eternal, and solid, and steadfast. Reflecting on how insignificant our lifespans are compared to God’s eternity is part of the lesson that “teaches us to realize the brevity of life, so that we may grow in wisdom.” (Psalm 90:12)
In both cases, I think the point is to say “even though we experience time one way, in God’s reality it is different” It feels like Jesus is taking a long time to come back, but… It feels like our lives are really long and important, but…
I don’t think there is anything to unlock in Genesis related to modern science. The ancients clearly had no concept of how old the earth was or of biological evolution. God gave them revelation that made sense in their worldview and imparted the spiritual truth they needed to know to worship him well and treat others justly.
Someone needs to design a teen magazine- style test where we answer a bunch of multiple choice questions and add up our scores so we can find out what kind of creationist we are. @BradKramer has been messing around with survey design today, so maybe we all need to convince him that it would be a valuable use of his time to make us one. Or maybe that’s what his “favorite fruit” question was really designed to reveal… Forum User Survey 1