How do astronomers believe the world was created?

Astronomers would not support any kind of interpretation that the world was "created" as this always implies a "creator". All of the evidence we have to date suggests that the world, sun, galaxy and the entire universe "emerged" by purely physical forces and there is no need to evoke a creator or created world.

The Big Bang is the best explanation we have for the development of the universe/galaxies and the Nebular Hypothesis is the leading idea on how the solar system and our Earth formed. Suggest you do a Socratic search for similar questions that can provide you with details.

The most common theory among astronomers is that the universe was formed about 13.8 billion years ago, during a process known as the Big Bang. This theory postulates that the universe started as a hot, dense point and has been expanding and cooling ever since.