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Other objects in the Solar System. Describe characteristics of the moon. Describe asteroids Describe meteors and meteorites. Describe comets. KEY WORDS Moon Lunar Satellites Comet Asteroid Meteoroid Meteorite Meteor . Io - only moon known to have active volcanoes
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Describe characteristics of the moon. • Describe asteroids • Describe meteors and meteorites. • Describe comets KEY WORDS Moon Lunar Satellites Comet Asteroid Meteoroid Meteorite Meteor
Io- only moon known to have active volcanoes Europa– contains more ice and water than Earth and may contain life.
(Oct 2008)– 172knownnatural moons orbiting planets in our Solar System.
Moon: Large natural object (rock/metals) that revolves around a planet – also called a satellites. • Roman goddess of the moon was Luna. • Most moons were discovered with telescopes. • Probes (robot explorers) have investigated moons of Mars, Jupiter and Saturn. • Studying moons helps us learn about the origin and evolution of the solar system.
Humans have visited its surface six times between 1969 and 1972. • First visit - SovietLuna 2 in 1959. • 2nd brightest object in sky. • No atmosphere • Surface filled with hills, valleys, and craters. • ¼ diameter of Earth • Its gravity is responsible for the tides of the oceans.
Asteroids: Chunks of rock/metal that orbit the Sunbut too small to be planets – minor planets. • “Asteroid belt” in large gap from Mars - Jupiter. • Largest is only 1000 Km in diameter. • Asteroids are rich in minerals – future mining. • Asteroid with orbits that cross paths with Earth are called Trojans. • Could cross close enough to be pulled in by Earth’s gravity and collide with it.
Meteoriods: lump of rock that is trapped by Earth’s gravity and pulled into the atmosphere. • As it falls, it rubs again molecules of air (friction) and becomes hot and breaks apart (vapourizes) so the air glows – burns up. • Meteoroid that completelyburns up - meteor. • Streak of light produced across the sky called also known as a shooting star. • The largest are probably asteroids.
Meteoroids that don’t completely burn up and strikes the Earth, it is called a meteorite. • Large meteorites make craters. • Westhawk Lake is a crater. Crater in Arizona formed by meteorite
Meteor shower Swarm of visible meteors when Earth passes through debris left behind by old comet.
Comets: chuck of ice/dust that orbit the Sun. • Made of the head (coma) and the tail. • Approach the Sun - warmed by solar radiation. • Heated material becomes glowing gas that is blown out by solar wind forming the tail – millions of km long. • Some comets have regular periods of revolution around the Sun. • Halley’s comet: last seen in 1986 it has a period of 76 years.