AIM: What are The Parts of the Solar System

Vocabulary

• Satellite

• Planet

• Sun vs Star

• Solar System

• Galaxy

• Meteor, Meteorite

• Asteroid

Telescope

Model of Solar System

Objects in a Solar System

• 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

• 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

AsteroidBelt

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 smoke-sized 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 Swift-Tuttle.

• 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

http://en.wikipedia.org/wiki/Image:NGC_4414_%28NASA-med%29.jpg