Solar System Movement of the Earth and Moon

1 Name _______KEY KEY_________ KEY Solar System Review Sheet *TEST ON Our Solar System • A solar system is a star and all of the objects that travel around it. • A star is a huge ball of glowing gas that gives off light and heat. Therefore, the sun is the star in our solar system. • A satellite is a smaller object that travels around a larger object. Gravity is the force that keeps each planet in its path around the sun. • Satellites of our sun are: planets, dwarf planets, asteroids, meteoroids, and comets. • The path a planet takes around the sun is its orbit. It’s not an exact circle. The orbit of the planets is oval-shaped, or an ellipse. • If you include Pluto, there are 9 major planets in our solar system. • To remember the order of the planets, use the mnemonic device from class: My Very Educated Monkey Just Served Us Nachos! Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune • All of the gases that surround a planet are its atmosphere. Characteristic Characteristic Material Diameter Length of orbit/year Rotation speed Number of rings rings Number of moons 4 Inner Planets (Mercury, Mercury, Venus, Venus, Earth, Earth, Mars) Mars) rocky with craters smaller shorter slower none few 4 Outer Planets (Jupiter, Jupiter, Saturn, Saturn, Uranus, Uranus, Neptune) Neptune) gas giant larger longer faster some many • Because of the tremendous size of our solar system, scale models help us show the relative size or distance of the planets. 2 Movement of the Earth • The earth moves in two ways: 1) The earth revolves around the sun. The path that the planet takes as it revolves is the planet’s orbit. One revolution around the sun is called a year. 2) The earth rotates, or spins, on its axis. An axis is an imaginary line through the center of a planet. One rotation of the earth is called a day. Therefore, we have day and night because the earth rotates on its axis. • A year on another planet may be longer or shorter than on earth because the planet’s orbit may be larger or smaller than earth’s orbit. Seasons on Earth • The northern part of the earth’s axis always points toward the North Star, also known as Polaris. • This causes the earth to tilt on its axis. Because of this tilt, we have seasons. • It is summer when your hemisphere is pointing toward the sun and we receive direct sunlight. Direct light from the sun is warmer and stronger. There are also more hours of daylight than night during the summer, causing the temperature to be warmer. • It is winter when your hemisphere is pointing away from the sun and we receive indirect sunlight. Indirect light from the sun is weaker and more spread out. There are less hours of daylight than night during the winter, causing the temperature to be cooler. • The northern and southern hemisphere have opposite seasons: Season in the Northern Hemisphere spring summer fall winter Season in the Southern Hemisphere fall winter spring summer • Seasons are NOT caused by how close the earth is to the sun. We know this because the earth is closest to the sun during January in the northern hemisphere! 3 • The vernal equinox is the first day of spring that occurs in March when the hours of daylight are equal to the hours of night time. • The summer solstice is the first day of summer that occurs in June and is the longest day of the year. • The autumnal equinox is the first day of fall that occurs in September when the hours of daylight are equal to the hours of night time. • The winter solstice is the first day of winter that occurs in December and is the shortest day of the year. Our Moon • Earth has one moon that revolves around us. • It formed about the same time as the earth. • Its surface has not changed in the past 3 billion years because there is no wind or water, so there is no erosion. • Asteroids have hit the surface of the moon causing craters. • The moon causes tides on earth – 2 high tides and 2 low tides each day. • The sun always lights up half of the moon. We see the moon’s phases because we see different amounts of the moon’s lit surface. • Here are the 8 phases of the moon: new moon waxing crescent first quarter waxing waxing gibbous full moon waning gibbous last quarter waning waning crescent • A solar eclipse is when the moon moves between the earth and the sun, causing a shadow to fall on the earth. • A lunar eclipse is when the earth moves between the sun and the moon, causing a shadow to fall on the moon. 4 The Solar System’s Rubbish • There are millions of other objects in the solar system other than planets and moons. • Asteroids are pieces of rock that orbit the sun. Most of them are in the asteroid belt between Mars and Jupiter. • A comet is a frozen chunk of dust, ice, and gases that revolves around the sun and has a glowing tail of melting ice. The tail points away from the sun. • A meteoroid is a chunk of rock and metal moving towards earth. As the chunk of rock shoots through the earth’s atmosphere, friction causes it to heat up and burn and it becomes a meteor. A meteor is another name for a shooting star! If the chunk of rock is large enough, it may not burn up completely. If it hits the earth’s surface, it is called a meteorite. • Draw a picture of the meteoroid - - meteor - - meteorite process: • If one of these space objects hits a planet, a bowl-shaped hole known as a crater forms.