1B1B

Did it start as a bang!

1B1B

The Expanding Universe

A. The Big Bang Theory:

Idea that all matter began in an infinitely small point and exploded out in all directions

1B1B

1B1B

Galaxies: _____________________ ___________________________________________________________

Billions of stars, dust, and gas held together by gravity

________________ was an astronomer in the 1920s who gathered many pictures of galaxies

• noticed they all didn’t look alike

• decided to classify them by the way they looked into 3 types

• “E” or _____________________

• “S” or _____________________

• “SB” or ____________________

Elliptical

Spiral

Barred Spiral

Edwin Hubble

A. Earth’s Galaxy—and Others

• Galaxies are grouped together in clusters.

• The cluster the Milky Way belongs to is called the Local Group.

• Three types of galaxies:

• Cluster of galaxies

Elliptical Spiral Irregular

Galaxy Morphological Revisted

The Hubble Tuning Fork

Spiral Galaxies

• Spiral Galaxies:

Circular galaxies that have arms curve outward from a central hub.

–Arms are made up of stars and dust

• Two spiral galaxies!!

Illustration/draw and label:

Spiral Galaxy

disk bulge

halo

Elliptical Galaxies Most common type of galaxy; large three-dimensional football shaped galaxies.

-Contain mostly older and dimmer stars.Vary in shape from completely round to extremely

elongated ovals. Unlike spiral galaxies

No bright nucleus at their center. Elliptical galaxies are represented by the letter E

Divided into seven subgroups according to their shape. These subgroups are labeled E0 to E7. E0 galaxies nearly circular in shape while E7 galaxies are extremely elongated or stretched out.

Illustrate / Draw Elliptical

Irregular Galaxies

• Come in many different shapes and are smaller and less common

• Irregular Galaxies - No regular shape, includes nebulas, with no central bulge or spiral arms.

Illustrate/ Draw:

Earth’s Galaxy

• Galaxy: A large group of stars, gas, and dust held together by gravity.

• Milky Way: Our galaxy which contains about 200 billion stars and many nebulas

• Spiral Galaxies

The Milky Way Galaxy• The Milky Way is the galaxy that contains our Solar System

which is just one of the several galaxies of the universe.

• . This name derives from its appearance as a dim "milky" glowing band arching across the night sky, in which the naked eye cannot distinguish individual stars.

• 100,000 light years in diameter

• Our sun orbits the center of the galaxy once every 240 million years

• A barred spiral galaxy

• Contains over 200 billion stars

• Its where we live!!!!!

Solar System

Our star (Sun), the planets, many moons, and other small bodies that

ALL travel around the Sun

Solar System

1B1B

What do we see in the sky?• The stars move in the sky but not

with respect to each other• The planets (or “wanderers”)

move differently from stars– They move with respect to the

stars– They exhibit strange

retrograde motion• What does all this mean?• How can we explain these

movements?• What does the universe

look like?

1B1B

The Great Debate! •Heraclides (330 B.C.) developed the first Solar System model, beginning of the geocentric versus heliocentric debate

1B1B

Timeline

Copernicus

1473-1543

Tycho

1546-1601Kepler

1571-1630

Galileo

1564-1642

Newton

1642-1727

1B1B

Geocentric (Ptolemaic) System

•The theory (in Greek, geo means earth), which maintained that Earth was the center of the universe, usually referring to the system of Claudius Ptolemy.

1B1B

Geocentric (Ptolemaic)

System• The accepted model for

1400 years• The earth is at the center• The Sun, stars, and

planets on their spheres revolve around the earth: explains daily movement

• To account for unusual planetary motion epicycles were introduced

• Fit the Greek model of heavenly perfection – spheres are the perfect shape, circular the perfect motion

1B1B

Illustrate/ Draw model:

1B1B

Heliocentric (Copernican) System• The word "helios" in Greek

means "sun." Heliocentric means that the sun is at the center. A heliocentric system is one in which the planets revolve around a fixed sun. Thus Mercury, Venus, the Earth, Mars, Jupiter and Saturn all revolve around the sun. The moon is the only celestial sphere in this system which revolves around the earth, and, together with it, around the sun.

1B1B

Heliocentric (Copernican) System

• Sun at center (heliocentric)• Uniform, circular motion

– No epicycles (almost)

• Moon orbited the earth, the earth orbited the sun as another planet

• Planets and stars still on fixed spheres, stars don’t move

• The daily motion of the stars results from the Earth’s spin

• The annual motion of the stars results from the Earth’s orbit

1B1B

Please Illustrate

Our Solar System

A Write On Activity

Our Solar System

Our solar system is made up of:

Sun Nine planets Their moons Asteroids Comets Meteoros

Inner Planets

The inner four rocky / Terrestrial planets. These planets have hard rock crusts, and dense rock and metal cores are:

Mercury Venus Earth Mars

1B1B

Mercury• Mercury is the closest planet to the Sun.• Mercury rotates the Sun in only 88 days.• Mercury rotates very slowly on its axis with one day

taking 58 Earth days.• Mercury barely has any atmosphere, but does have

glaciers.• Called a morning star. This is because Mercury

shines brightly in the early morning just before the sun rises. It has also been called an evening star for the same reason. Mercury is often visible for a brief period of time just after the Sun sets.

Venus Sister planet to Earth Size and

structure is VERY similar to Earth, often called "Earth's Twin"

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 Called "the Red Planet" because it surface is covered with iron oxide- RUST! Proves that Mars once had free oxygen molecules in its atmosphere.

Surface features volcanoes and huge dust storms

Has 2 moons: Phobos and Deimos

Outer Planets

A gas giant (sometimes also known as a jovian planet after the planet Jupiter, or giant planet) is a massive planet with a thick atmosphere of hydrogen and helium

Jupiter Saturn Uranus Neptune

Jupiter

Largest planet in solar system Brightest planet in sky 60+ moons, 5 visible from Earth Strong magnetic field Giant red spot Rings have 3 parts: Halo Ring,

Main Ring, Gossamer Ring

Saturn 6th planet from sun Seven thin, flat rings not solid but made

up of particles of ice, dust and rocks 31 moons Largest moon, Titan, Easily visible in the night sky A lightweight planet and it spins so fast Voyager explored Saturn and its rings.

Uranus 7th planet from sun Has a faint ring system 27 known moons Covered with clouds Sits and spins on its side with the north and south poles sticking out the sides.

Neptune 8th planet from sun Discovered through math 7 known moons Triton largest moon Storm called the "Great Dark Spot"

because it appears as a dark oval shape on the surface of the planet.

Great Dark Spot thought to be a hole, similar to the hole in the ozone layer on Earth

Pluto our dwarf

Pluto, the outermost planet, is a small, icy "dwarf planet“ it is smaller than the Earth's Moon.

Pluto 9th planet from sun

(usually) Never visited by

spacecraft Orbits very slowly Moon, Charon, is

very close to Pluto and about the same size

Comet- chunks of ice and dust

• Has an elliptical orbit around Sun• Has a head (nucleus and coma) and

tail.• Tail always points away from sun.

Comets: Orbit

Asteroids-

Larger chunks of rock Vary in size and shape In Asteroid Belt between Mars

and Jupiter Revolve around sun in 3-6 years

Asteroids: Illustrate /draw

Meteoroids- smaller chunks of rock and dust in space.

1. randomly move about space ; no specific orbit

2. come from remains of comets and asteroids

• Meteor- a meteoroid that burns in the atmosphere- produces a streak of light.

nickname: “Shooting star”•MeteoriTe- a meteoroid that doesn’t

burn up in the Earth’s atmosphere. It Touches Earth.

Writing Activity

Which does not describe the difference between Gas Giants and Terrestrials?A. Terrestrials are closer to the sun than gas giants.B. Terrestrials are denser than Gas Giants.C. Gas Giants rotate faster on their axis then Terrestrials.D. Terrestrials have rock and metal in their core and Gas Giants do not.

Solar SystemActivities

Order the Planets  Fun with Planets Constellations of the

Northern Sky Planets Solar System