What is Earth Science? A. EARTH SCIENCE: the study of Earth and its history B. Earth science is divided into 4 main branches:

1. GEOLOGY: study of the lithosphere 2. OCEANOGRAPHY: study of oceans 3. METEOROLOGY: study of weather and climate 4. ASTRONOMY: study of space

What is astronomy? A. ASTRONOMY: the study of stars, planets, and other objects in

space B. Astronomers want to understand the universe and our planet’s

part in the universe. 1. Space exploration started with its study from earth using

telescopes. 2. Our study of space now takes place in space using a great

deal of technology.

What is the universe? A. UNIVERSE: the whole of space

and everything in it 1.  It is believed to be infinite in

volume 2.  The observable universe is a

sphere around earth with a radius of 46 billion light years.

B. The universe is getting larger. 1.  There are galaxies moving out

and away from earth in every direction.

2.  This is evidence of how the universe may have started. a.  BIG BANG THEORY: the

universe started as a very dense point known as the SINGULARITY that exploded outward

What are some major features of the universe? A. GALAXY: a large collection of stars,

dust, and gas that travel through space as one body. 1.  Most galaxies are grouped together

close to one another 2.  There are three categories of

galaxies: a.  SPIRAL GALAXIES: galaxies

shaped like flattened disks b.  ELLIPTICAL GALAXIES:

galaxies shaped like spheres c.  IRREGULAR GALAXIES:

galaxies with no definite shape 3.  Galaxies are held together by gravity

a. Many galaxies are held together by the gravity of black holes

What are some major features of the universe? B. STARS: spheres of gases

and plasmas that give off a lot of energy 1.  Most stars are

composed of hydrogen and helium

2.  Stars form from a cloud of gas and dust called NEBULA

3.  Most stars move through space in large groups called STAR CLUSTERS.

4.  Stars are classified by its surface temperature and brightness.

Where is Earth located in the Universe? A. The Earth is an inner planet in

the Solar System located in the Milky Way Galaxy. 1.  The Milky Way is a part of a

group of galaxies called the Local Group.

2.  The Solar System is located on Orion’s Arm, one of the spiraling arms of the Milky Way.

B. The Milky Way is a spiral galaxy. 1. The center of the galaxy is a

massive black hole . 2. The gravity of this black

holes holds the Milky Way together

What are the major parts of the Solar System? A. SOLAR SYSTEM: a collection of astronomical objects held in

orbit around the Sun (Sol) by gravity . 1.  The Sun is a medium sized star called a yellow dwarf. 2.  The larger objects of the Solar System are 8 planets:

a.  INNER PLANETS: Mercury, Venus, Earth (Terra), Mars b.  OUTER PLANETS: Jupiter, Saturn, Uranus, Neptune

B. There are other major parts of the Solar System: 1. ASTEROID BELT: a ring of rock, dust, and ice that encircles

the inner planets. 2. KUIPER BELT: a ring of mostly ice that lies out on the edge

of the Solar System past the outer planets 3. DWARF PLANETS: very small planets found in the Asteroid

& Kuiper Belts 4. MOONS: natural satellites that orbit a planet 5. COMETS: small objects of ice and dust that have irregular

orbits around the Sun

How do the inner and outer planets differ? A. The four inner planets have a number of similarities:

1.  Composed of rock. 2.  Small in size 3.  Closer to the sun 4.  Surrounded by the Asteroid Belt

B. The four outer planets have a number of similarities. 1.  Composed of gas 2.  Large in size 3.  Further from the sun 4.  Outside the Asteroid Belt

How space is explored? A. NASA: National Aeronautics and

Space Administration 1.  A federal agency responsible for

exploring space. B. Rocketry is how NASA gets off

Earth’s surface. 1.  ESCAPE VELOCITY: the speed

and direction required to escape Earth’s gravitational pull.

2.  They must travel at 25,000 mph to fight earth’s pull

How space is explored? C. Satellites, probes, landers &

rovers are all other means of exploration 1.  JPL: Jet Propulsion

Laboratory 2.  JPL works to design, build

and test vehicles for exploration.

D. NASA is developing & testing new vehicles for exploration. 1.  CSTS: Constellation Space

Transportation System 2.  NASA will use ISS to test

equipment designed for a permanent base on the moon

2.  Earth’s distance from the Sun puts it in an orbit inside the habitable zone for a yellow dwarf star a.  GOLDILOCKS ZONE: the habitable zone around a star where the

distance is just right for life to possibly exist b.  The temperature on the planet is mild, allowing for liquid water

How is Earth effected by its position & movement in the Solar System? A.  Facts about Earth’s position and movement in the Solar System:

1.  Earth’s distance from the Sun: a.  Average of 93 million miles b.  Distance changes due to an imperfect orbit

3.  Earth’s movement around the sun is called a revolution: a.  REVOLUTION: the movement

of one astronomical body around another

b.  ORBIT: the path an astronomical body takes as it revolves around another

c.  Distance of one Earth revolution: 584,000,000 miles

d.  Length of time for one Earth revolution: 365 days and 5 hours (1 year)

4.  Earth’s movement around its axis is called a rotation: a.  ROTATION: the spinning of an

astronomical body around its axis b.  Earth’s axis is tilted 23.5 degrees c.  Length of time for one Earth

rotation: 24 hours (1 day)

5.  The north pole of the axis always points in the same direction as Earth revolves around the Sun.

6.  This locked position of the north pole allows different areas of the planet to receive different levels of sunlight throughout the year.

How does the moon effect Earth? A. MOON: a natural satellite with a rotation that orbits a planet B. The Earth has one moon named LUNA.

1.  The moon is believed to be a large part of Earth’s crust blown into space through a collision with another inner planet named Theia.

2.  One full lunar revolution is 27 days 3.  One full lunar rotation is 27 days. 4.  Only one side of the moon is ever seen from Earth.

b.  WANING: phases of the moon that occur when light decreases and darkness increases

5. PHASES OF THE MOON: the lunar cycle of shapes the moon takes over 27 days as day and night move across its surface a. WAXING: phases of the moon that occur when darkness decreases

and light increases