The phrase "earth science" is used to refer broadly to the scientific disciplines that study our planet. Studies of the lithosphere (which includes geology, geophysics, geochemistry, and geography), the hydrosphere (which includes hydrology and marine, ocean, and cryospheric sciences), and the atmosphere (which includes meteorology and climatology) are all included. So, Earth science is a wide range of related physical, chemical, and biological fields that study things that have been happening on Earth for billions of years, from the subatomic to the planetary level.