The bright point of light which thus seems to us to be a star when we look at it with the naked eye is really another world, or _planet_ as it is called, and very like our own Earth. To prove that this moving point of light is really a world, or planet, and not a distant star, all you need to do is to look at it through a pair of opera glasses, or a small telescope, when it will be seen to be a round body, whereas a star when viewed through the greatest telescope is never larger than a mere point of light. (See Fig. 50.) [Illustration: FIG. 50.—A STAR AND A PLANET IN A TELESCOPE.] The reason the planets, some of which are smaller and some larger than our Earth, can be seen to move is because they are quite near our Earth; that is, they are near when compared with the fixed stars. Again, the reason the planets shine like the stars is not because they are hot and flaming bodies like our Sun and the other stars, but because the light from the Sun which strikes them is reflected to the Earth in exactly the same way that the sunlight falling on a mirror is reflected away in another direction. =Names and Sizes of the Planets.=—The names of all the planets, and there are eight chief ones, should be learned as well as the order in which they are arranged around the Sun. The names of the planets are given below in the order of their _size_. MERCURY—The smallest planet and the one nearest the Sun. Pale ash in color. Has no moon. MARS—The Red Planet. Reddish in color. Has two moons. VENUS—Called the Evening Star. Brilliant straw in color. Has no moon. EARTH—Our own planet. Has one moon. URANUS (pronounced Yew´-ra-nus)—Called Herschel’s planet. Pale green in color. Has five moons. NEPTUNE—The planet farthest away from the Sun. Has one moon. SATURN—The planet with the rings. Its color is a dull yellow. Has ten moons. JUPITER—The largest planet. He is marked with lines called belts. He has nine moons. Bright silver in color. THE ASTEROIDS—A group of small planets, the largest of which is about 500 miles in diameter. =How to Know the Planets.=—While it is not an easy thing to tell a planet from a star with the naked eye, still there are several ways of doing it. First, always look for the planets along the path which the Sun and Moon travel. As all the planets are nearly in the same plane with the Sun and Moon they must all follow the same path across the sky. Second, it is useful to remember that none of the planets, except Mercury, ever twinkle, unless they are very near the horizon. Third, by watching a planet closely for a few hours it will be found to have moved a little. To note this change of position the planet and some fixed star near it must be closely watched and their distances compared from time to time. Fourth, and last, the surest way of finding the different planets is by using an almanac which will tell you which planets can be seen at certain times of the year and in what part of the sky they are to be found.