According to this article, much of Earth's water is older than the solar system. How is that possible?
Our solar system is not a first generation solar system. It condensed from a vast cloud that contained contents from an older solar system or systems. The mass of the cloud or our Sun (after the cloud condensed) may also have captured material that was passing by, possibly thrown by an exploding star.
At the outer edges of our solar system is the Oort Cloud. It contains debris that didn't get swept up in the formation of our Sun and planets. Some is from that cloud and some is captured. Occasionally, gravitational perturbations will pull a comet from that vast distance in, towards the Sun. A comet can be composed of ice. The theory is that some of those comets hit the young Earth, depositing their ice and thus providing the water that forms our oceans.
Thus the water in our oceans may be remnants of other solar systems that existed before ours was formed. Our oceans may have been oceans on other planets before they were ours. Entire alien civilizations may have sailed upon that water. They may have drank that water. They may have passed it through their bodies. That bottle of water you are sipping, as you read this, might be seven billion-year-old alien pee.
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