Which sentence is punctuated correctly?

Our sun is a star, the stars we see in the sky are actually faraway suns
Our sun is a star; astronomy is the study of objects in the sky
Our sun is a star; the stars we see in the night sky are actually far-away suns
Our sun is a star, astronomy is the study of objects in the sky

1 answer

Our sun is a star; the stars we see in the night sky are actually far-away suns