system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:How old is the water in the oceans? My aunt asked me this question and it sparked quite a debate. How do we know the age of water? If the water on Earth came here by way of an asteroid or whatever then is it even possible to know the age of the water here on Earth.
gpt
Water is rarely created on Earth.  It's also rarely destroyed on Earth. The same water molecules cycle from being in the ocean to being in the atmosphere to falling as precipitation to flowing back to the ocean.    That process doesn't describe age.  It describes someone who moves homes alot.