Simplify the following text for a Grade 6 native English-speaking person.
Original: It contains 100-400 billion stars and an estimated 50 billion planets , 500 million of which could be located in the habitable zone of their parent star . The Milky Way is part of the Local Group of galaxies and is one of around 200 billion galaxies in the observable universe .
Simplified: It contains over 200 billion stars , including our Earth and Sun .