What dictated how much land mass Earth got when it was created and will we get more?
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Clarity question. Are you referring to the mass of earth as in all land even that under the ocean or only the part of the crust visible above the ocean?
The Sun ignited as a star and started spewing the solar wind into the disk of dust around it. This encouraged disk to clump up into planets. There is some evidence that Jupiter may have run over a planet that was just outside where Mars is now, rubbling it and perhaps sending what would become the Moon to crash into the Earth.
The mass for Earth, plus or minus that collision with what is now the Moon, was determined by the dust in our “lane”. The concentration of water came from ice in that dust plus cometary bombardment in the early solar system.
We get a little more every year, what are called meteorites. Sometimes we lose some if we shoot it off in spacecraft, but that’s nothing like the mass that falls in to the Earth.
TLDR: Volcanism and continental drift are responsible for most of the land mass above water, and it is increasing albeit very slowly.
In terms of land mass if you mean the continents, that is steadily increasing.
The amount of water on Earth’s surface remains effectively constant but the increasing height and mass of the continents creates more land.
Billions of years ago very little of Earths surface was above water, but the continents steadily grew to what they are now. The most stable parts of the continents are called the cratons. Massive rocks formed when the Earths crust was still molten. Chunks of early crust folded together to create massive floating islands of rock on magma which formed the basis for the continents.
By comparison the Earth’s crust under the oceans is quite thin compared to the continents and is constantly being subducted and recycled into the Earths mantle due to continental drift.
The continents meanwhile are being thrust upwards into mountain ranges, and adding material through Volcanism. The rate of this has slowed considerably compared to several billions years ago though.
Islands like Hawaii don’t last long geologically speaking. As the plate moves over the Volcanic hotspot the volcano that forms Hawaii will move to a new location. The islands will start to erode away and a few million years from now they will be almost entirely gone. You can actually follow the chain of islands formed by the Hawaii hotspot on a map. Eventually the plates will move enough that whatever is left of the islands will pile onto the nearest continent.
The continents meanwhile are growing faster than they are eroding, but at a snails pace over millions of years.
If you mean the continents, they are basically chunks of the crust that have been mashed together tso they’ve gained height in the form of mountains. The ocean just fills in the low areas. As the polar ice caps grow and shrink over thousands of years, sea level changes so you’ll see more or less land mass above the surface. Plate tectonics will tell you more of how the continents are made.
All of earth is covered with land. We just have a certain amount of water that fills in the lower parts. We’d get more land if land squished together or otherwise made other higher peaks, or if we get less water.
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