4 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 doesn't contain all the wonders that have been discovered Our planet shares the solar system with many other worlds They all have wonderful things to see THE BUILDING BLOCKS OF THE SOLAR SYSTEM After a house is built a big pile of material is always left over The same thing happened after the formation of the solar system The Sun and the planets were formed from a huge cloud of dust and gas This dust and gas came together to form tiny clumps of rock metal and ice These tiny clumps gathered into bigger clumps After millions of years these clumps were large enough to become the Sun and the planets
5 The asteroid belt in the solar system is made up of the orbiting pieces of rock ice and metal left over after the planets and the Sun formed This illustration shows a view of the Sun from an asteroid Not all the matter in the original dust cloud was used up Chunks of rock metal and ice were left over These are what we call asteroids and comets and meteors They are important wonders because they are remnants of the very earliest beginnings of our solar system
1 Ceres Ceres is the largest object in the solar system's asteroid belt Modern astronomers have classified it as too small to be a planet
7 IT'S A DARK NIGHT IN 1801 AND THE SICILIAN ASTRONOMER GIUSEPPE PIAZZI IS LOOKING FOR COMETS HE NOTICES A TINY STARLIKE OBJECT SINCE IT MOVES SLOWLY ACROSS THE SKY FROM NIGHT TO NIGHT HE THINKS HE HAS FOUND A NEW COMET BUT HE DISCOVERS THAT IT HAS AN ORBIT A PATHWAY AROUND THE SUN MORE LIKE A PLANET THAN A COMET HE NAMES IT CERES AFTER THE PATRON GODDESS OF SICILY BUT HE IS DISAPPOINTED WHEN HE CALCULATES ITS SIZE CERES IS LESS THAN 500 MILES 800 KILOMETERS WIDE BARELY ONE QUARTER THE SIZE OF EARTH'S Moon CERES ISN'T BIG ENOUGH TO DESERVE THE NAME PLANET MERCURY MARS MAIN ASTEROID BELT VENUS EARTH JUPITER Many asteroids can be found in the asteroid belt which orbits the Sun between Mars and Jupiter
