Why is the world suposst to becoming to an end in 2012?

People in my family talk a lot about the world ending in 2012 but i try and just drown them out because nobody knows but god. If god is ready then he is ready but people who are preparing to what good does that do.? Anyways i dont think it will end. There are soo too many theories out there right now like nibiru crossing and how and solar flares asteroid meteors floods. idk, what u think??