QQQ has huge tech exposure, but it is not a 'tech fund' in the pure sense either. The fund's arcane weighting rules further distance it from anything close to plain vanilla large-cap or pure-play tech coverage.
During the time when Earth was forming and was in a molten state, heavy materials like iron and nickel sank to the center of the Earth's mass and lighter materials floated to the surface of the mass. The very center of what we call the core, is solid in the middle because of the increased pressure in that region.
Thus all the heat from radioactive decay comes from the crust and mantle â about eight terawatts from uranium 238 (238U), another eight terawatts from thorium 232 (232Th), and four terawatts from potassium 40 (40K).nitially the earth heated up using energy released buy gravitational collapse, and while this energy completely melted the planet, this heat would have all been lost by now as the Earth is 4.6 billion years old. However, the earth is still hot in its core as we can see from all the volcanic activity on our planet.