Not to really ruin all the determination for others who are working so hard to figure out #4, but here is the biggest hint yet! (Got it from a really good friend, so i'll tell it my way)
Day 2 #4 If you figured out that it's digits showing 1.523a.u it actually means 1.523000 which is distance. It's so massive, it reaches out from Earth to Mars. Now, knowing Greek Mythology, what does Mars represent? That shall be your answer, and this hint is a big give away
Sorry if I offended anyone by posting this, but we are all a team and I feel people deserve to not overstress about this Quiz, that we can overcome it! I personally thank ajluczak and Glamorgan for helping me pass Days 2 with useful Hints!