A day as it is now,....or a day as it was THEN?
Imagine an observation post which is a stasis bubble in which our laws and time flows exist. We can sit in that Bubble and watch as the universe flashes into existence and time that exists out side of that bubble flows incredibly fast....centuries are mere micro seconds, millenia mere seconds....stars form, burn briefly then flare up and go nova in a minute....geologic processes on various planets progress rapidly, mountains rising falling, oceans receding then progressing...almost like one views a film or dvd going at high speed then slowing, slowing, slowing,..... while you watch the Earth start to form day 1, then day two, you watch as the genesis pattern occurs; from your perspective and experience in stasis, you live literally 6 days while centuries flash by in a blink...but still slowing, slowing, slowing.....7th day God rests and the space/time flows around your stasis bubble have slowed to match that of your stasis bubble....you can step out now! Adam?!
That is what they are talking about with this “big bounce” theory... and if there is any truth to it then it solves the issue of how the Earth was created in 6 days, while appearing older than its apparent history.