Planets and Stars
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Transcript of Planets and Stars
Stars• Were noticed even before telescopes.
• Balls of glowing hot gas.
• Did not change position in the night sky.
Planets• Objects that changed position from night to
night against the stars.
• Large bodies orbiting a star.
• The Sun’s gravity keeps them in orbit.
• There are 8 planets in our solar system.
Early Idea of the Solar System
• Earth did not move
• Earth was at the center of the Solar System
• The stars, Moon, and Sun revolved around Earth
Copernicus Solar System
• The Sun was at the center of the universe
• Was very unpopular when it was introduced
The Two Solar System Models
• http://www.youtube.com/watch?v=iiBIFlvu-X0&feature=related
• Rocky or metallic
• Orbit the Sun
• Too small to be considered a planet
• Some astronomers believe they are material that never combined to form a planet.
Asteroid Belt• Most are located between the orbits of Mars
and Jupiter
• Some travel from Saturn’s orbit, others have orbits that cross Earth’s path.
Asteroids that have hit Earth
• http://www.meteorcrater.com/
• http://geology.com/meteor-impact-craters.shtml
• Small asteroids
• Some travel to the edge of the solar system
• Others stay within the orbits of the inner planets
Meteoroids
Meteors
• When a meteoroid hits Earth’s atmosphere. – The meteor rubs against Earth’s atmosphere
producing heat.– This heat causes the meteor to burn.• Try rubbing your hands together to produce heat.
• Seen as a bright streak of light.
Meteorite• Any part of a meteoroid that reaches Earth’s
surface.
• 3 types:– Stony – made out of rock– Metallic – made from metals like nickel and iron or
a mixture of metal and rock– Carbonaceous – rich in carbon
Meteor Shower
• When many meteoroids hit Earth’s atmosphere at the same time.– Often happens after a comet has traveled past Earth.
• Some occur year after year.– Perseid Meteor Shower happens around August 11
2103 Meteor Showers
• http://stardate.org/nightsky/meteors
• Perseid Meteor Shower Time Lapse:– http://
www.theguardian.com/science/video/2013/aug/13/perseids-meteor-shower-timelapse-video
• http://video.search.yahoo.com/search/video;_ylt=A2KLqIT4lFZSD0EA5c_7w8QF;_ylu=X3oDMTBncGdyMzQ0BHNlYwNzZWFyY2gEdnRpZAM-?p=2013+perseid+meteor+shower&ei=utf-8
Parts of a Comet n
• The nucleus is the main, solid part of the comet
• The coma is a halo of evaporated gas (water vapor, ammonia, carbon dioxide) and dust that surrounds the nucleus
• The comet's dust tail always faces away from the sun.
A Comet’s Orbit• As it comes closer to the Sun the cometbegins to melt.
• The melted ice and dust becomes the comet’s tail.
• The tail gets pushedaway from the Sun from the pressure.
Where a Comet Comes From
• Kuiper Belt– A region beyond Pluto’s orbit– Probably contains 40,000 to 70,000 objects with
diameters of more than 100 km. • 100 Kilometers = 62.1371192 Miles
• Oort Cloud– Surrounds the solar system about 15 trillion km
from the Sun
Hailey’s Comet
• Orbits past Earth every 76 years.
– The last close pass was in 1986, and the next is due in 2061.
Layers of Earth• Inner Core• Outer Core• Mantle• Crust – What we live on
• Hydrosphere– Thin layer of water
• Atmosphere– Thin layer of gases
Earth’s Atmosphere
• Protects us from small debris from space.
• Made up of:– Nitrogen (78%)– Oxygen (21%)– Other gases (1%)
Atmospheric Layers• Troposphere– Nearest Earth’s surface– Where weather occurs
• Stratosphere– Ozone helps absorb harmful ultraviolet radiation from the Sun
• Mesosphere
• Thermosphere
Magnetic Field• The area that surrounds a magnet.– Invisible lines of force that run from one pole to the other.
• Earth has one as if there were a giant bar magnet buried inside it.