Vocabulary STUDENT RESOURCE 1.1 INFORMATION SHEET asteroids thousands of rocky objects that orbit the Sun Most asteroids orbit in a belt between the orbits of Mars and Jupiter. More than 9, asteroids have been identified. Only about 2 are more than 1 kilometers in diameter. comet object made of frozen gases, dust, and rock, that orbits the Sun Comets have long, bright tails when they pass near the Sun. The tails always point away from the Sun, no matter what direction the comet is moving. meteor rock that enters and burns up in Earth s atmosphere Meteors are often called shooting stars because they flash across the night sky in a bright streak. meteorite rock that strikes the surface of a planet or moon Meteorites can cause impact craters where they hit. The Barringer Crater in Arizona was formed by a meteorite. It is about 1.2 kilometers in diameter and 2 meters deep. planet a large object in space that revolves around a nearby star There are nine planets in our solar system. In order from the Sun, they are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. scale model a model that correctly shows relationships between size and distance, but is smaller or larger than the objects it represents Scale models are often used in science to study very large or very small objects. solar system the Sun and the objects that orbit it, including the nine planets The solar system formed some 4.6 billion years ago when a cloud of gas and dust contracted into a large, spinning disk. The Sun formed in the hot, dense center of the disk. The rest of the gas and dust eventually formed planets. EXPLORING SPACE SECTION 1 THE PLANETS 11
Our Solar System STUDENT RESOURCE 1.2 INFORMATION SHEET Object Distance from Sun (kilometers)* Diameter (kilometers)* Moons Rings Period of Rotation (in Earth days)* Period of Revolution (in Earth days or years)* Features Sun 695,5 25 days surface temperature 6,1 K, mostly hydrogen and helium, makes energy by fusing hydrogen into helium Mercury 58,, 4,88 59 days 88 days rocky planet, steep cliffs, cratered surface, extreme temperature changes ( 173ºC night to 427ºC day) Venus 18,, 12,14 243 days 225 days rocky planet, rotates backward compared to other planets, hottest planet (over 45ºC), covered in thick clouds, atmosphere of carbon dioxide, no water Earth 15,, 12,756 1 24 hours (1 day) 365.25 days rocky planet, land and ocean areas, polar ice caps, varied land features, only planet with life or liquid water Mars 228,, 6,794 2 25 hours 687 days (about 2 years) rocky planet, red surface, polar ice caps, seasons, volcanoes (including largest in solar system), canyons Asteroids Varies; most lie between Mars and Jupiter Varies from 94 km to less than 1 km Some have, most do not Varies Varies; largest takes 4.6 years More than 9, have been found and numbered. Some moons of planets may be captured asteroids. Jupiter 778,, 142,984 63** 1 1 hours 12 years gas giant, strong east-west winds, giant swirling red storm, strong magnetic field Saturn 1,427,, 12,536 35** Thousands 1.6 hours 29 years gas giant, less dense than water (could float), five main rings, thousands of small rings; Its moon Titan is bigger than Mercury and has an atmosphere. Uranus 2,871,, 51,118 27** 11 17 hours 84 years gas giant, rotates backward compared to most other planets, icy insides, rotates on its side, very cold ( 215ºC) Neptune 4,498,, 49,532 13** 6 16 hours 165 years gas giant, strong winds, very cold ( 235ºC); Its moon Triton orbits opposite to Neptune s rotation. Pluto 5,96,, 2,3 1 6.4 days 248 years smallest planet of all, made of rock and ice, tilted orbit; Its moon Charon is half its size. Varies from Comets Highly variable 94 km to less than 1 km Varies; less than 1 to 3 million years Mostly made of ice. Comets grow tails when passing near the Sun. Tails always point away from Sun. *All values are averaged and rounded. **Numbers may change as new moons are discovered around gas giants. 12 EXPLORING SPACE SECTION 1 THE PLANETS
Making Model Planets STUDENT RESOURCE 1.3 ACTIVITY SHEET Draw a circle 1 cm in diameter on the posterboard to represent Earth. Use the table below to determine the sizes of the other planets in your scale model. Planet or Sun Actual Diameter (km) Diameter Relative to Earth (cm) Sun 1,391,9 19 Mercury 4,879.38 Venus 12,14.95 Earth 12,756 1. Mars 6,794.53 Jupiter 142,984 11.21 Saturn 12,536 9.45 Uranus 51,118 4.1 Neptune 49,572 3.89 Pluto 2,32.18 EXPLORING SPACE SECTION 1 THE PLANETS 13
Find Planets in the Sky STUDENT RESOURCE 1.4 HOMEWORK SHEET Imagine a sky map as the inside of a bowl. Hold the bowl above your head and look up. The center of the map is straight up and the circle is the horizon. Because the map shows the sky above you, east and west are reversed. If you look south and hold the map overhead, east and west will be correct. Draw each planet on the sky map. Write the time to look for it. Is it low, medium, or high in the sky? (Low is near the circle edge.) Go outside at night with an adult. Use this map to find planets. Planet: Planet: Planet: Time: Time: Time: NORTH EAST look up WEST SOUTH * East and west read correctly when sky map is in use. Parent / Guardian signature: 14 EXPLORING SPACE SECTION 1 THE PLANETS
World s Largest Meteorites STUDENT RESOURCE 1.5 ACTIVITY SHEET 1 Take turns plotting these meteorites on a world map. Location Number of Tons Location Number of Tons (approximate) (approximate) Namibia 6 West Greenland 2 Argentina 27 Tanzania 16 West Greenland 31 Mexico 14 China 28 USA (Oregon) 14 Mexico 22 Australia 12 2 Use the data in the table to make a bar graph comparing the sizes of these meteorites. Use a sheet of graph paper. Determine a scale for your graph. Give your graph a title. Label both axes. 3 How many times heavier is the largest meteorite, compared with the smallest one on this list? Show your work. EXPLORING SPACE SECTION 1 THE PLANETS 15
Section 1 Assessment STUDENT RESOURCE 1.6 ASSESSMENT SHEET Vocabulary Write the term on the line that describes each object. 1 Ceres is a rocky object with an orbit between Mars and Jupiter. 2 Hale-Bopp is made of ice and grows a tail when it passes near the Sun. Planets in the Sky The two maps show objects in the sky six months apart. 3 Which object is a planet? Circle it in both maps. 4 Explain how you knew that the object was a planet. Scale Models 5 Jupiter has over sixty moons. The diameters of two of them are listed here. Metis: 4 kilometers Thebe: 1 kilometers Use the metric ruler to draw scale models of Metis and Thebe. Draw them on the back of this paper. Use a scale of 1 millimeter equals 1 kilometer (1 mm = 1 km). (Hint: How many millimeters wide is Metis, using this scale?) 16 EXPLORING SPACE SECTION 1 THE PLANETS