Transcript Lesson Review

AIM: What are The Parts of
the Solar System
Vocabulary
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Satellite
Planet
Sun vs Star
Solar System
Galaxy
Meteor, Meteorite
Asteroid
Telescope
Model of Solar System
Objects in a Solar System
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a star - the Sun
planets, which go around the Sun
satellites, which go around planets
smaller objects such as asteroids
and comets
Satellites
• Natural – moons
• Manmade - satellites
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Weather
Mapping
Communication
Defense
War
Satellite Radio
The Moon
• The Moon is the natural satellite of the
Earth.
• It orbits the Earth but no-one built it or
launched it into space.
• Gravitational forces between the Moon
and the Earth keep the Moon in orbit.
JUPITER’S MOONS
Artificial Satellites
• Some satellites are used to collect information
about the planets and stars.
• The Hubble Space Telescope can see further
into space than telescopes based on the ground.
• Its view is not blocked by clouds and it doesn't
have to wait for night-time.
• However, it is difficult and expensive to launch
and maintain.
Space Probes
• Space probes do not orbit the Earth
• Instead, they travel to other planets to collect
scientific information.
• People have been to the Moon, but it would take
too long to send people to other planets.
• Some space probes go into orbit around other
planets, some land on them, and some even
journey out of the solar system.
Asteroids
• Small objects which orbit the Sun
• Mostly between Mars and Jupiter
• Perhaps a planet which never formed
Asteroid
Belt
Comets
• 900 comets have been identified
• About 200 have regular observed orbits
• Frozen ice, gasses, dust
Facts about Comets
• nucleus: relatively solid and stable, mostly ice and gas
• dust tail: up to 10 million km long composed of smokesized dust particles
• ion tail: as much as several hundred million km long
composed of plasma and caused by interactions with the
solar wind.
• Comets are invisible except when they are near the Sun.
Meteor Showers
• Meteor shower sometimes occur when the
Earth passes thru the orbit of a comet.
Some occur with great regularity:
• Perseid meteor shower occurs every year
between August 9 and 13 when the Earth
passes thru the orbit of Comet SwiftTuttle.
• Comet Halley is the source of the Orionid
shower in October.
Heliocentric Model
• People used to think that the Earth was at
the center of the universe
• We now know that the Sun is at the center
of the solar system,
• Earth and other planets go around it.
• We say that the planets are in orbit around
the Sun
• This is the Heliocentric Model
Model of Solar System
What Keeps the Solar System
Together?
• All objects have a force that attracts them
towards each other.
• This is called gravity.
• Newton’s First Law
Gravity and the solar system
Gravitational forces between the Sun and
planets keep the planets moving in orbit
around the Sun.
Without these forces, the planets would fly
off into deep space.
Their orbits are slightly squashed circles
called ellipses.
What is a Glaxay
• Our galaxy contain is the Milky Way
• Has over 100 billion stars (suns)
• The nearest galaxy is Andromeda is about
2-3 million light years distant.
This light may have taken 13 billion
years to arrive at Earth