how did water appear in Earth and how did we end up with such vast amount of it?



how did water appear in Earth and how did we end up with such vast amount of it?

In: Earth Science

We’re not exactly sure, but a leading theory is asteroids with water bombarded the Earth and provided the bulk of the water, with a significant fraction coming from comets and maybe 1-2% from the solar nebula (the disc of gas surrounding the sun).

Water is Hydrogen + Oxygen, two of the most abundant things on Earth.

Much of the Earths crust is made up of Oxygen, bonded to other things like Iron to make minerals.

Since a lot of Oxygen existed on the primeval Earth, and Hydrogen is the most abundant thing in the Universe, having water was inevitable.

So where did it come from? Either the Earth was formed from material that contained a lot of Oxygen and Water, or the early Earth was bombarded with Comets and Asteroids that contained Oxygen and Water.

Water is really common in the universe. It’s made of hydrogen (by far the most common element) and oxygen, which is made by stars and not very rare either. Water is found on/in all the gas giants, on many moons, and most/all objects out near pluto, in the Kuiper belt.

I don’t know if we do have a huge *amount* of it; some moons of Jupiter and Saturn have tons and tons of water ice. Mars had a huge amount of liquid water, but it’s all either frozen or swept away now that the planet has no magnetic field (along with its atmosphere). Venus probably lost whatever water it formed with to solar wind in the same way.

Once upon a time, there was hydrogen, and it came together because even though it’s a tiny particle, it still has mass and gravity, and more and more gathered together into a star. That star got so big and heavy that it started to mush the hydrogen atoms into helium, and then helium into lithium, and so on. And at some point, that star became unstable and exploded, filling the surrounding space with all kinds of planet stuff. Some of that planet stuff included hydrogen and oxygen, lots of it and as we know from fire, hydrogen and oxygen mix pretty easily when an ignition source is involved. Boom! Big fiery reaction… and the hydrogen and oxygen are now… you guessed it, together as water molecules!

Genesis 1:1

In the beginning God created the heaven and the earth.

2 And the earth was without form, and void; and darkness was upon the face of the deep. And the Spirit of God moved upon the face of the waters.

“Vast amount” is a relative term here. The total amount of water on Earth is still only about a millionth of the total volume of the planet–by any normal measure, that would actually make the place rather dry! It’s just because our atmosphere and temperatures mean we have liquid water on the surface that it’s quite so obviously part of our world.

Two theories. Either two elements combined. Oxygen, which is bonded with other things in the ground. and hydrogen, which is everywhere. OR meteors had frozen water on them in the early years of earth. As for the abundance of water, there isn’t really that much. If you shrunk the earth down to the size of a standard size globe, all the water would be about 14mL.

1. Probably an ice meteor got us started
2. After we had a little bit, primitive life and eventually bacteria started to break down the goop that was primordial Earth and giving us the atmosphere and oceans

As others point out oxygen and hydrogen aren’t really rare in the universe, but the reason we have liquid water and other planets don’t, is because we have an atmosphere which traps sunlight (greenhouse effect) and keeps us cozy and warm. Magnetosphere has a part to play in this as well, since it protects life from all sorts of nasty radiation from the Sun and allows this process to continue.