I went to sleep last night and my world ended. I woke up again this morning just fine and started anew. Not all things ending are bad, you know?

This world as we know it must end for the sake of our children's future. Surely, you can at least see that much of what is being done here today is not sustainable. However, my definition of the world ending differs greatly from what you are describing. Sure, there are doomsday folks out there. But many see issues with the world. Inequality, greed,war, etc... too much to list. We want this world to change for the sake of everyone! But not end in the worst senses of the word! Also, the word world can be defined a number of ways too...

Your daughter sounds like she is very smart,observant and intuitive. My humble suggestion is to expand on what ending really means. Give her some positive definitions of it to work with in her mind. You know you can't keep her from the rest of the world. She will hear and see things that you don't want her to experience. Again, a humble suggestion, don't feed into it by getting upset at others. She will always trust you more than any other source as long as you are honest with her and speak from the heart.

I don't know if you would call this common sense or optimism but my short answer to her would be that if the world does end this year all it means is that people will stop being mean to each other and start loving each other more.

I don't think there are many believers in the hoax called 2012. The few believers are in such a minority that they would have great difficulty in manipulating enough people to cause a run on the banks.

I have no evidence to suggest otherwise, other than the fact that the earth has been here for a very very long time and has seen it's share of catastrophes, but I feel like this 2012 Dooms Day issue is totally blown out of control. The fact of the matter is that most events work in cycles and what is the ending for some is a new beginning for others.
I am doubtful that 7 billion people will all of a sudden die off or that the earth will spontaneously explode. But I have a feeling that the end of this year will offer a catalyst that will noticeably, and perhaps rapidly, alter how we live on this planet. I see it as the dawn of a "new age" of sorts; maybe better, maybe not, or maybe in the long run the same as this one.
But using the phrase "the end of the world" seems like a misnomer and an unfair generalization that creates an hysteria that is damaging to our culture.

Just my opinion...