Scientists believe that there are two main options: we could blow up the asteroid with nuclear weapons or we could make it change direction. Both options have their disadvantages. If we blew up the asteroid, it could break into smaller pieces.
Each piece could then be a danger! There are several ideas about how to make an asteroid change direction, but nobody knows which would work best -and it`s impossible to test the technology. And if we failed, we probably wouldn`t get another chance.