If you are referring to the planet, then yes, you should capitalize it, as you would capitalize Mars, Jupiter, Pluto, and other planet names. If you are referring to the bro…wn stuff underfoot, then no, you do not capitalize it. As a general rule, you capitalize proper nouns; that is, nouns that are names applied to unique things such as: London, Abraham Lincoln, Earth, etc..(MORE)
Much of the heat in the Earth's core is left over from the formation of the planet, when planetesimals collided releasing large amounts of energy. Much of that leftover energy… is what we see today as heat in the center of the Earth. Smaller planetary bodies cool more quickly and have lost most of their heat (moon, mars) and have cooled to the point of being solid. \n.
\nThe center of the Earth is also hot due to the gravitational pressure of the Earth above. A simple experiment to show how pressure can increase temperature is to squeeze an ice cube and see it melt, or pump up a bicycle tube and feel the pump. Although not quite correct for solids, the ideal gas law of T = PV/nK gives a relationship between temperature (T), pressure (P), volume (V), the number of atoms (n), and a constant (K). Thus you can see how temperature can increase as pressure increases. However, in spite of the high temperatures and pressures, the Earth's inner core is solid. \n.
\nThe insides of stars have extreme pressures due to the gravitational attraction of so much material. Like in the earth, gravity in turn, creates high pressures and high temperatures. However, in stars, the high-pressure, high-temperature condition allows for fusion of Hydrogen to Helium (etc.) which releases much energy and heat and which we see as light from the stars. This can not occur in the Earth (or even Jupiter) because there is not enough gravitational pressure (not enough mass), and (for Earth anyways) not enough Hydrogen.\n.
\nSome energy is transfered to the Earth through gravitational forces from the Moon's orbit. As the Earth spins (once per day) there are gravitational stresses on the surface due to the gravitational field gradient from the Moon. This causes surface effects such as tides and flexes the crust which provides some heat (through friction), but this is not enough to account for the high temperatures seen in the core, nor for the increasing temperatures seen the closer to the Earth's core you get.\n.
\nThe earth's core is not hot due to friction from the continents moving, since the Earth's temperature increases steadily the farther down from the surface you go. Again, while friction will cause some heating, and it does contribute to some of the heat seen, it does so in specific areas (convection layers) and does not account for the high temperatures found at the core, nor does friction account for the steadily increasing temperatures seen.\n.
\nThe earth's core is not hot due to radioactivity since the core of the Earth is largely iron and nickel. Many of the radioactive elements are found mostly near the surface. Besides, the amount of radioactive material needed to generate the temperatures seen in the Earth's core would make the planet a radioactive wasteland. (MORE)
As is described in the Silmarillion the elves originated in Middle-Earth in its far eastern part, as also did Men much later. But for their safety as Morgoth and his follo…wers held control of much of Middle-Earth at the time the Valar summoned the elves to leave their homes in Middle-Earth and cross the Great Ocean to travel to the land of Valinor to live with the Valar. Some elves refused (the avari) and dropped out of the histories of the elves at that time, other elves (woodelves, Sindarin elves) came partway but never left Middle-Earth (these are thus known as the elves of darkness, as they never saw the original light of Valinor in the time of the Two Trees). But there are two returnings of elves from Valinor to Middle-Earth: Feanor had made three great jewels called Silmarills that captured and held the light of the Two Trees. When Morgoth came and poisoned the Two Trees and stole the Silmarills, Feanor and his sons swore a great oath of vengeance on Morgoth and to recover the Silmarills. So he, his sons, and many other Noldorin elves (relatives and followers) returned to Middle-Earth to make war on Morgoth. When Morgoth was greatly oppressing those in Middle-Earth the man Earendil a great sailor took the one Silmarill (that Beren the grandfather of his wife Elwing had recovered from Morgoth) to Valinor to request assistance from the Valar, the Valar agreed and came to Middle-Earth along with a great army of elves. They defeated Morgoth, recovered the other two Silmarills (but they were soon stolen by the sons of Feanor trying to fulfill Feanor's oath), and the First Age ended. Most of the elves then in Middle-Earth left for Valinor. Occasionally throughout the Second and Third Ages ships of the Telerian elves would arrive at ports of Middle-Earth to trade with the elves of Middle-Earth and took back with them those that wished to leave. The final elvish ships taking the last of the elves to Valinor departed from the Grey Havens early in the Fourth Age, no elves have been in Middle-Earth since that time. (MORE)