The ideal scenario in dealing with the penny is as follows:
- People take it seriously Day 1. Everyone knows there's a penny doubling in size that will threaten humanity if left unchecked.
- The World Powers agree to work together to deal with the threat.
- Someone's got a rocket capable of launching the penny into space.
- If no rocket is on hand humanity is pretty much ****ed.
- Scientists run path calculations for the penny to send it into the Black Hole at the middle of the universe
- On Day 1 (or 2, maybe 3) the Penny is launched into space and blasted with at least half the nuclear capacity of the entire world.
- Instead of one large blast, have there be at least three, with some nukes following the penny far into space to keep it going
- Hopefully the Penny is blasted far enough to the point where humanity remains relatively safe. Ideally it ends up in the Black Hole somehow.
- If it ends up hitting some debris (which it surely will) hopefully it's not slowed down too much. Maybe turn some nukes into long range remote detonation missiles to keep it going if the penny slows down.
Of course, this is incredibly unlikely and humanity is likely ****ed if the penny can't be broken down. I give Humanity a 3/10 tops.