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A nearby star exploded and the shock wave caused the gas to gravitationally pull into itself creating our sun and a planetary disc around it.
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The first hundred thousand years the dusts and gases collide into each other creating chondrules which essentially are the building blocks of a solar system. The chondrules through gravitational pull and turbulence collided into each other forming clumps. By the end of the one hundred thousand years the clumps will be as large as 1 km long which will allow it to accrete on its own.
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The accretion continues on for another ten million years. The inner rocky clumps are growing into planetesimals, though the outer planets are becoming much bigger as its colder which makes dust and clumps attach more easily. This might also explain why Jupiter and Saturn are so gassy and not dense, because it doesn't take too much pressure to make Jupiter and Saturn grow.
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The planetesimals are really taking shape into our planets we know today. Around this period larger objects are colliding with each other and right in the middle of this period around 60-70 million years the moon was formed with a big collision.
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Pluto sized objects crashing into Earth and the other planets depositing metal.
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Around 60 million years ago a large object the size of Mars crashed into Earth creating lots of heat. The molten parts of Earth and the Mars size object floats out into space forming into our moon.
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Heavier elements like iron start descending into Earth effectively forming it core. It descended because most of Earths surface was still very hot and molten.
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There is a theory that the solar system was very chaotic around this time because Saturn and Jupiter decided to move towards the inner planets going through the asteroid belt. Their gravitational pull flung asteroids to the inner planets then migrated back out. Many things could have hit earth like comets carrying ice or water which would explain why earth has water.
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Earth does start to cool down but the features were formed by heat.
The heat from the core is trying to escape Earth and the radioactive elements on Earth heats it up even more. The heat allows the core to spin and keeps the molten metal to remain there. It also probably is the source of earths strong magnetic fields. Additionally as the heat was trying to escape it fractures the surface of earth creating tectonic plates. The heat created many of earth's habitable features.
