In the nebular hypothesis (which has been extensively falsified, yet kept because people's careers are resting on it) establishment has no explanation as to why the Earth still has active lava flows, earthquakes, water oceans and a magnetic field... and Mars, Venus and Mercury do not?
Tell me, if they all came from some disk, why do they appear dead and lifeless, without magnetic fields, lava, earthquakes and oceans? So somehow Earth just magically retained these properties and the other did not? Even though Earth is smack dab in the middle of the bunch?
The reason why they do not have lava flows, magnetic fields, oceans and earthquakes is because they are much older, dead stars which have almost completely solidified after many billions of years of cooling, far beyond the Earth. They are older than the Earth. According to establishment dogma they are all the same age. Unfortunately establishment is full of idiots. Stars that have cooled much further along their evolution will not have magnetic fields or lava. This is predicted via stellar metamorphosis:
If you will notice, the further down to the lower right hand side of the graph means the older the star. Notice how Mercury, Mars and Venus are past the Earth by significant amounts. This is impossible to establishment dogma.