Please choose the correct answer to the question: In the 1500s, Nicolaus Copernicus proposed a new theory on the heliocentric structure of the solar system. Which of these statements best describes this new theory?

Answer1: Earth is at the center of the solar system. Answer2: There are eight planets in the solar system. Answer3: The Sun is at the center of the solar system. Answer4: Moons have circular orbits in the solar system.

Answer format: answer1/answer2/answer3/answer4