On Friday, May 24, 2019 at 9:46:04 AM UTC-5, palsing wrote:
https://www.jpl.nasa.gov/news/news.p...ily-20190523-2

"The mystery of why Earth has so much water, allowing our "blue marble" to support an astounding array of life, is clearer with new research into comets. Comets are like snowballs of rock, dust, ice, and other frozen chemicals that vaporize as they get closer to the Sun, producing the tails seen in images. A new study reveals that the water in many comets may share a common origin with Earth's oceans, reinforcing the idea that comets played a key role in bringing water to our planet billions of years ago."

Comets are dirty snowballs. They don't have enough water to fill up the Earth's oceans.