The formation of Earth, around 4.5 billion years ago, bore some resemblance to the formation of the sun. Gravity pulled a lot of stuff together and crushed it, somewhat like a child would form a hard snowball, but there wasn't enough mass to cause the kind of pressures required to start a fusion reaction.
Still, the early Earth was mostly molten, not because of pressure, but because space debris rained down on it and blasted the surface. In fact, soon after the formation of the planet (in geological terms) a huge asteroid hit it and knocked a considerable glob of molten crust out. That became our moon.
There was an atmosphere but, if it contained oxygen, it reacted with everything else until it was all quickly bound up. In that hellscape, there was no life (although life did form much earlier than scientists though a decade ago.) There was no liquid water. It would have quickly boiled off. There were no oceans or continents. Space would have been completely obscured from the surface by dense clouds of methane, ammonia, nitrogen, sulfur, and water vapor. If there was rain, it would have been acid
The reason we have nowhere near the bombardment now that early Earth sustained, is that we've pretty much swept our orbit clear of major impact bodies.
It took about a billion years for the Earth to cool off enough and to gather the raw materials (water, oxygen, carbon dioxide...probably a little from volcanic venting and a lot from bombardment by icy space debris), to create life.
Young Earth was not the same planet we have now. The crust has been thoroughly shuffled and reshuffled. The planet has been "terra-formed". It would be impossible to pinpoint a spot that would become Walnut Hill.
By 3.5 billion years, Earth had a magnetic field. Heavy metals, mostly iron and cobalt, but most elements heavier than silicon, sank to the core. The center most part of the core remained solid because of the pressure exerted on it by the surrounding material, but the outer core was (and is) molten. Currents in the molten core created a natural dynamo that produced a magnetic envelope around the planet. That helped to, among other things, hold onto a dense atmosphere. It was a "greenhouse atmosphere" that kept the planet hot and, as water collected on the surface, it didn't melt. There was no ice.
On Young Earth, if you were standing at latitude 39.7392 north and longitude 104.9859 west (the coordinates of present day Denver), you would probably be standing in lava. If you managed to find solid rock to stand on, it would be basalt. The crystalline, granitic rocks, sedimentary and metamorphic rocks you see all around you today didn't exist on Earth then. The air was from volcanic outgassing. There was very little oxygen and a lot of unbreathable stuff like carbon dioxide, methane, ammonia, sulfur dioxide...oxygen is very reactive and doesn't like to hang around in free state. To maintain an oxygen rich atmosphere, oxygen has to be continuously generated. That's why plants are so important to us. The streams I've talked about having been so large in the past didn't exist on Young Earth...there was no liquid water. The sky was colorful and dark.
The surface of Earth was made up of basalt. It's the kind of rock you find on the ocean floor and underlying the continents today. It's what happens when molten rock is extruded onto the Earth's surface to cool quickly. Oceanic crust, basalt, is heavier than continental rock, and it has more heavy elements like iron, making it dark. In fact, a very important fact for understanding geology is that continental crust floats on denser basaltic crust.
Young Earth went through a period of differentiation. The laws of physics were well established by then... everything worked the same way that it works today. Heavy sinks down through light, so the heavy elements sank down through the lighter elements. Most of the iron and cobalt ended up in the core. Gold, for instance, so important historically to Denver, is one of the rarest elements in the Earth's crust. Here's a chart of the predominance of all the elements in the crust (from Wikipedia, "Abundance of the Chemical Elements"), . Gold is rarer than most of the "rare earth" elements like niobium, yttrium, and tantalum. It's down in the super-rare, yellow area.
Gold is so rare for two reasons. First, the most common elements are those that make up stars (it's called "stellar nucleogenesis.") Stars produce elements by fusion, starting with hydrogen and deuterium and sticking atoms together to form the lighter elements like carbon, silicon and iron. It stops at iron. Once fusion starts, it can continue as long as the reaction doesn't require the input of energy from the outside. As the atoms created get larger and larger, less energy is created by the reaction. After iron, energy must be fed into the system to continue fusion.
At the end of a large star's life (our sun is much too small), it explodes. The energies produced are spectacular and a supernova is created. That's where gold is produced. The space junk that our solar system was created from was contaminated by the remains of some supernova.
Another factor against the production of gold is that fusion starts by sticking together atoms with even numbers of neutrons and protons in their nuclei, deuterium and helium, so larger atoms with even numbers of particles are favored. The only stable isotope of gold has 79 particles in it's nucleus.
The other reason gold is so rare in the crust is that most of it sank to the core with iron and cobalt. What's in the crust mostly came with later space junk, dust, meteors, and asteroids, and a little made it's way from deep inside the Earth by convection currents and random diffusion.
About a billion years after Earth formed, life appeared...
