There isn't one single science that studies our planet Earth. Instead, it's a combination of many different fields, each focusing on different aspects. Here are some of the main ones:

* Geology: The study of the Earth's physical structure, composition, history, and processes.

* Geography: The study of the Earth's surface, including its landforms, climate, and human populations.

* Oceanography: The study of the Earth's oceans, including their physical, chemical, and biological properties.

* Meteorology: The study of the Earth's atmosphere and weather patterns.

* Climatology: The study of the Earth's climate and climate change.

* Environmental Science: The study of the interactions between living organisms and their environment.

* Ecology: The study of how organisms interact with each other and their environment.

* Geophysics: The study of the Earth's physical properties, including its gravity, magnetic field, and seismic waves.

So, depending on what aspect of the Earth you're interested in, you'd be studying a specific science.