Title The Solar System.pdf ✅

The Solar System
Revolution and Rotation  The planets revolve around the sun in orbits that lie close to a common plane. The orbit of Mercury, the closest planet to the sun, is tipped 7° to Earth’s orbit.  The rest of the planets’ orbit planes are inclined by no more than 3.4°.  The solar system is basically flat and disk shaped.  The rotations of the sun and planets on their respective axes seem related to the direction of orbital revolution.  The sun rotates with its equator inclined only 7° to Earth’s orbit, and most of the other planets’ equators are tipped less than 30°.  The rotations of Venus and Uranus are peculiar. Venus rotates backward compared with the other planets, whereas Uranus rotates on its side (with its equator almost perpendicular to its orbit).
Two Kinds of Planets  The two kinds of planets are distinguished by their location and masses.  The four inner Terrestrial planets are quite different from the four outer Jovian planets.  Craters are common. Almost every solid surface in the solar system is covered with craters.  The two groups of planets are also distinguished by the presence or absence of rings and numbers of moons.
Space Debris  The solar system is littered with three kinds of space debris: meteoroids, asteroids, and comets.  The asteroids, sometimes called minor planets, are small rocky worlds, most of which orbit the sun in a belt between the orbits of Mars and Jupiter  A thousand small, dark, icy bodies orbiting in the outer fringes of the solar system beyond Neptune is called the Kuiper belt after astronomer Gerard Kuiper  In contrast to the rocky asteroids and dark Kuiper belt objects, the brightest comets can be seen with the naked eye and are impressively beautiful objects.