Seven Wonders of the Rocky Planets and Their Moons
Seven Wonders of the 7 Seven Wonders of the Rocky Planets and Their Moons Ron Miller TwenTy-FirsT CenTury Books Minneapolis
inTroduCTion People love to make lists of the biggest and the best almost twenty-five hundred years ago a greek writer named herodotus made a list of the most awesome things ever built by people the list included buildings statues and other objects that were large wondrous and impressive later other writers added new items to the list writers eventually agreed on a final list it was called the seven wonders of the ancient world The list became so famous that people began imitating it They made other lists of wonders They listed the Seven Wonders of the Modern World and the Seven Wonders of the Middle Ages People even made lists of undersea wonders and the wonders of science and technology But Earth isn’t the only place with wonders Our planet circles the Sun along with many other worlds whaT are The roCky PlaneTs Three kinds of planets orbit the Sun One kind is the rocky planets such as Earth Venus Mars and Mercury These planets have a crust an outer layer made of silicate rocks It is this kind of rock that gives the 4
This illustration shows the planets and their moons The rocky planets Mars Earth Venus and Mercury are the four small planets closest to the Sun Earth’s Moon is also visible in this illustration rocky planets their name The second are the gas giant planets These are planets made mostly of gas and liquid They are Jupiter Saturn Uranus and Neptune Some astronomers scientists who study the moon the stars and other aspects of space call the icy world of Pluto a third kind of planet The rocky planets are made mostly of stone and metal Earth for example has an outer crust or a shell of mostly rock and an inner core of mostly iron and nickel The other rocky planets are similar They hold deep canyons tall mountains poisonous skies and the magic of life Wonders can be found on every one of them 5
