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.
âThe inner planets (Mercury, Venus, Earth and Mars) all formed from the disk of gas and dust, the solar nebula, that surrounded our young sun.â âOf the four inner planets, also known as terrestrial or rocky planets, Mercury is the smallest, oldest, and densest.â âThe eighth planet from the sun, its gaseous structure contrasts with the rocky inner planets.â âThe inner planets move fast, and make repeated transit cycles over the course of a few months or years; the outer planets move much more slowly, but the contacts they do make are often very significant.â