Earth and Space

Our Solar SystemOur solar system is made

up of: Sun Eight planets Their moons Asteroids Comets Meteoroids

Inner PlanetsThe inner four rocky

planets at the center of the solar system are:

Mercury Venus Earth Mars

Mercury

Planet nearest the sun Second smallest planet Covered with craters Has no moons or rings About size of Earth’s moon

Venus

Sister planet to Earth Has no moons or rings Hot, thick atmosphere Brightest object in sky besides

sun and moon (looks like bright star)

Covered with craters, volcanoes, and mountains

Earth

Third planet from sun Only planet known to have life

and liquid water Atmosphere composed of

composed of Nitrogen (78%), Oxygen (21%), and other gases (1%).

Mars

Fourth planet from sun Appears as bright reddish

color in the night sky Surface features volcanoes

and huge dust storms Has 2 moons: Phobos and

Deimos

Outer Planets

The outer planets composed of gas are :

Jupiter Saturn Uranus Neptune

Pluto

Dwarf Planet Never visited by

spacecraft Orbits very slowly

Asteroids

Small bodies Believed to be left

over from the beginning of the solar system billions of years ago

100,000 asteroids lie in belt between Mars and Jupiter

Largest asteroids have been given names

Comets

Small icy bodies Travel past the Sun Give off gas and

dust as they pass by

Meteoroids Meteoroid: A small particle from

a comet or asteroid orbiting the Sun.

Meteor: The light phenomena which results when a meteoroid enters the Earth's atmosphere and vaporizes; a shooting star. 

Meteorite: A meteoroid that survives its passage through the Earth's atmosphere and lands upon the Earth's surface.

RotationRotation versus versus RevolutionRevolution

RotationRotation is the turning of a body about an axis. The earth rotates once every 24

hours. RevolutionRevolution is the motion of one

body around another. The earth revolves around the

sun once every 364 ¼ days.

Why Do We Have Why Do We Have Seasons?Seasons?

The tilt of the Earth’s axistilt of the Earth’s axis and the revolution around the Sunrevolution around the Sun cause the Earth to have seasons.

Combined Effects of Tilt and Combined Effects of Tilt and RevolutionRevolution

Earth’s Seasons - YearEarth’s Seasons - Year

Why Does The Moon Have Phases?

Phases of the moon are determined by: The relative positions of the

earth, moon and sun. Revolution of moon around the

earth. Your position on the earth.

Instruments and technology used in astronomy

Instruments and technology used in astronomy

Refracting telescope: collects & amplifies light using lenses

Reflecting telescope: collects & amplifies light using mirrors

Binoculars: uses two refracting telescopes to observe 3D objects

Radio telescope: collects & amplifies radio waves emitted by celestial bodies

Radar: measures the distance between the Earth and celestial bodies

Observatory: building that provides the best possible conditions to observe the universe

Satellite: object place around a celestial body to collect/transmit data

Instruments and technology used in astronomy

Space probe: Unmanned spacecraft launched into space to explore celestial bodies

Space rocket: Unmanned spacecraft launched into space, with only one salvageable section

Space shuttle: A salvageable spacecraft launched into space capable of returning to Earth

Space station: A facility place in orbit around the Earth (or other celestial body) that is designed for habitation and to carry out various missions

Measurements in astronomy

AU: Astronomical unit = 150 million km

Distance between the Earth and the Sun

Light year: 9 500 billion km

Pluto (not a planet)

The 2006 debate surrounding Pluto and what constitutes a planet led to Ceres being considered for reclassification as a planet.

A proposal before the International Astronomical Union for the definition of a planet would have defined a planet as "a celestial body that

(a) has sufficient mass for its self-gravity to overcome rigid-body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and

(b) is in orbit around a star, and is neither a star nor a satellite of a planet"

Ceres (not a planet)

However, and on 24 August 2006 a modified definition was adopted, carrying the additional requirement that a planet must have "cleared the neighborhood around its orbit".

By this definition, Ceres is not a planet because it does not dominate its orbit, sharing it as it does with the thousands of other asteroids in the asteroid belt and constituting only about a third of the mass of the belt. Bodies that met the first proposed definition but not the second, such as Ceres, were instead classified as dwarf planets.

Solar system

A solar system refers to a star and all the objects that travel in orbit around it. Our solar system consists of the sun - our star - eight planets and their natural satellites (such as our moon); dwarf planets; asteroids and comets. Our solar system is located in an outward spiral of the Milky Way galaxy.

Solar system

Galaxy

a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction.

ICW/Homework

P.293 #1,2,5,6,7 P.294 #10,11,18 P.295 #22,25