| A | B |
|---|
| The study of the universe. | astronomy |
| Polish astronomer who proposed a sun-centered solar system. | Copernicus |
| The first person to use a telescope to view the stars and planets. | Galileo |
| Determined that the shapes of the orbits of planets were ellipses. | Kepler |
| Ancient civilization whose philosophers placed the Earth at the center of the universe. | Greek |
| Made up of the the sun and all the objects that orbit it. | solar system |
| What does the term "geocentric" mean? | Earth-centered |
| What does the term "heliocentric" mean? | Sun-centered |
| Name the four inner planets. | Mercury, Venus, Earth, Mars |
| Name the five outer planets. | Jupiter, Saturn, Uranus, Neptune, Pluto |
| Solid, rocky planets with iron cores best describe the inner planets or outer planets? | inner planets |
| Planets that are gas giants best describe the inner planets or outer planets? | outer planets |
| The average distance between the sun and the Earth is called a/an ___. | astronomical unit |
| This planet appears red because of the iron oxide (rust) in its rocks. | Mars |
| Which planet is called Earth's twin or sister planet because of its similar size and mass? | Venus |
| This life-supporting planet has water existing under natural conditions in all three states: solid, liquid and gas. | Earth |
| This planet has the shortest period of revolution around the sun. | Mercury |
| This planet is the largest in the solar system. | Jupiter |
| This planet has the lowest density and hundreds of thin rings. | Saturn |
| This moon is closest to Jupiter and has active volcanoes. | Io |
| For about 20 years, this blue-green gas giant was fartherest from the sun.was | Neptune |
| The Great Red Spot is a continuous storm found on ___. | Jupiter |
| This gas giant has a tilted axis that is nearly parallel with the plane of its orbit so that it appears to "roll". | Uranus |
| The solid portion of a comet is its ___. | nucleus |
| The path of a planet around the sun is called its ___. | orbit |
| These two space probes visited the outer planets during the 1980's. | Voyager 1 and 2 |
| This space probe landed on Mercury in 1974. | Mariner 10 |
| These two probes sent pictures from Mars in 1976. | Viking 1 and 2 |
| This invention was needed for the discovery of Uranus. | The telescope |
| Which of the outer planets is most like an inner planet in terms of its size and composition? | Pluto |
| The term that describes how much longer an ellipse is than it is wide is called ___. | eccentricity |
| How many focii does an ellipse have? | 2 |
| The cloud of gasses around the solid portion of a comet is known as the ___. | coma |
| The asteroid belt is located between which two planets? | Mars and Jupiter |
| The Great Dark Spot is a huge whirlwind found on which planet? | Neptune |
| The blue-green color of Uranus and Neptune is due to the presence of what gas? | methane |
| Like Pluto, this planet has only one moon. | Earth |
| A "dirty snowball" from space composed of dust, rock particles, frozen water and gases. | comet |
| A cloud of comets that some astronomers think surrounds the solar system. | Oort Cloud |
| A group of meteors. | shower |
| Broken pieces of rock moving through space. | meteoroids |
| Part of a comet formed by the gases streaming away from the sun. | tail |
| A meteoroid that burns up in the Earth's atmosphere. | meteor |
| The mean distance of the Earth from the sun is 93 million miles. What does "mean distance" mean? | average distance |
| A meteoroid that strikes Earth is called a ___. | meteorite |
| The sun changes hydrogen to helium to form energy in a process known as ___. | fusion |
| What must be done to the length of a string to make an ellipse more circular if the two focii (tacks) remain fixed? | Lengthen the string |
| If the length of a string remains the same, what must be done to the distance between the two focii (tacks) to make it more circular? | Move the tacks closer together. |
| If an ellipse becomes more eccentric, it means that its shape is less ___. | circular |
| This Greek philosopher placed the Earth at the center of the universe. | Aristotle |
| This early, modern astronomer thought that the orbits of the planets around the sun were circles. | Copernicus |
| These two planets, when seen from Earth will always appear close to the sun. | Mercury and Venus |
| On this planet a day is longer that a year because of its very slow rotation. | Venus |
