I am Earth, a rocky planet in the solar system. I was formed 4.5 billion years ago from a dust and gas disk. I have an atmosphere mostly composed of nitrogen and oxygen, a magnetic field, and an ozone layer. Additionally, I have liquid water on my surface, which is essential for life. I have life on all my continents and oceans, including plants, animals, and microorganisms. I am constantly changing due to my geological activity and human influence. I am unique in the known universe.