According to science theory the Earths water source had to come externally. Asteroids were thought to be the origin but then a comet was found with similar water to Earth.
But comet 67P's water is very different to earths.So if ice mountain comets, that are rocky, are not our planets water source, the theory now switches back to asteroids.
But asteroids are rocky bodies themselves, so where would they have the water? Ancient wet asteroids is the suggestion.
“Today asteroids have very limited water; that’s clear,” says study leader Kathrin Altwegg of the University of Bern. “But that was probably not always the case.” A wealth of geological evidence suggests that a barrage of water-rich impactors struck the Earth and other rocky planets nearly four billion years ago, a time when asteroids were probably wetter and far more numerous than they are today.
Rosetta pours cold water on cometary origins of Earth’s oceans
Earths water from wet asteroids?
It seems science may be suggesting that Asteroids were wetter in the distant past, when they were hitting early Earth and emitting all that wet water. But now they are drier.
As suggested and predicted by the Electric Universe theory comets are not dirty snowballs but rock and are not the the source of Earths water. Comets are active asteroids as comet 67P and others have shown.
Perhaps Earths water could have come from inside the planet? Or from its interaction with the solar wind (plasma) such as the water found on the Moon or around comets/asteroids? Or perhaps according to some catastrophe ideas transferred from another wet planet?