Here's a bit more detail:
* Plate Tectonics: The Earth's outer layer (the lithosphere) is made up of massive plates that are constantly moving. At mid-ocean ridges, these plates are pulling apart, a process called sea-floor spreading.
* Magma Upwelling: As the plates separate, magma (molten rock) rises from the Earth's mantle and erupts onto the ocean floor. This creates new crust, pushing the plates further apart.
* Mountain Formation: Over millions of years, the continuous eruption and cooling of magma builds up, forming massive undersea mountains called mid-ocean ridges.
These ridges are truly colossal, extending for tens of thousands of kilometers around the globe. They are a major feature of the Earth's surface, even though they are hidden beneath the ocean!
