Iâve come up with fewer reasons for giving a child a cell phone earlier, but at least two of them are enough to offset a multitude of others. Keeping tabs on them. As each year passes in a childâs life they venture farther from home and for longer periods of time.
Like the inner planets, the outer planets have similar characteristics to one another. The outer planets are so much larger than the inner planets that they make up 99 percent of the mass of the celestial bodies that orbit the Sun. Although mainly composed of gas, the outer planets also have other ingredients.
Most of the iron is in the core of the earth. Most of the oxygen is locked up in minerals with silicon. In fact, the mineral quartz is made up of only silicon and oxygen. The inner planets are relatively small and mostly solid, though earth has a thin atmosphere made up mostly of nitrogen and oxygen gases.