4 MEET A MORNING STAR Mercury is one of the eight planets that orbit or travel around the sun in the solar system It is the closest planet to the sun which has made it a huge challenge for scientists to study Its average distance from the sun is about 36 million miles 58 million kilometers It travels around the sun at a faster speed than any other planet This image of Mercury was captured by a camera aboard the MESSENGER spacecraft
5 Mercury is mentioned in myths and stories in cultures around the world It was named after the Roman god Mercury the swift-footed messenger of the gods Why might the planet have been named after this god THINK ABOUT IT Because Mercury is so close to the sun the best time to see it from Earth is at sunrise or sunset Mercury is known as a morning star at certain times of the year when it appears in the sky just before sunrise At other times it appears as an evening star just after sunset Dawn is one of the best times to view Mercury which is also called a morning star
6 TAKE A LOOK AT MERCURY Mercury is the smallest planet of the solar system It is less than half the size of Earth In fact it would take eighteen Mercurys to fill up the inside of the Earth Mer cury is so small that it is smaller than some planets moons Mer cury’s diameter or distance through its center is about 3,030 miles 4,900 km It is as wide as Earth’s Atlantic Ocean Mercury’s land scape includes flat Mercury is not even half the size of Earth In fact Mercury is the solar systemʼs smallest planet
7 VOCABULARY A mantle is the middle part of a planetʼs inside that lies between the crust or surface and the core or center plains and long steep cliffs Pits called craters scar its sur face The craters form when chunks of rock or metal called meteorites hit Mercury Some parts of the sur face have many cra ters while other parts are very smooth The surface of Mercury does not have any water Like Earth Mer cury has three separate layers a metallic core a rocky mantle and a thin rocky crust Meteorites crash into Mercuryʼs surface and form craters as seen in this photo graph taken on January 14 2008
