system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Does the Earth produce it’s own water naturally, or are we simply recycling the worlds water again and again?

Assuming that we class all forms of water as the same (solid - ice, gas, liquid) - does the Earth produce water naturally?
gpt
There's the water cycle, which you already know, but there are other processes too. Biologically, water is created and destroyed all the time. Photosynthesis breaks water up into it's hydrogen and oxygen atoms and combines them with the atoms from carbon dioxide to make sugar. In cellular respiration, that sugar molecule is broken down and turned back into carbon dioxide and water molecules. So when you pee, a good chunk of that could be brand new water molecules.

Even without biology, water molecules are constantly swapping hydrogen atoms with each other. In any drop of water, you'll find a few hydroxide and hydronium ions as the hydrogen atoms are traded around.

The amount of water on earth is pretty constant because any process that breaks up a water molecule also has its opposite. Hard to say how old any specific molecule is, though.