Our Universe Billions of galaxies made up of billions of stars

Our Own Solar System The Sun and the Planets that orbit it

The Sun – Our Star The closest star to Earth Medium size Yellow Main Sequence Star 150,000,000 Km (93 Million miles) away billion years old Will last about another 5 billion years Located near the edge of our disc shaped galaxy – The Milky Way

The Suns Planets Celestial bodies that orbit a star

Our Milky Way Galaxy

Comets Rocky material made of gas dust and ice that orbit the sun

Meteors Space Rocks known as shooting stars when they enter the Earth’s atmosphere. Become meteorites when they hit the Earth’s surface

Asteroids Small rocky bodies known as minor planets Orbit the sun mainly between Mars and Jupiter (asteroid belt)

Stars Huge bright balls of gas

What are Stars? Gigantic spheres of gases held together by gravity Generate huge amounts of energy because of nuclear reactions of hydrogen and other elements. Radiate electromagnetic radiation. –Light, heat and other forms of energy There are 100 billion stars in our own galaxy!

Stars The Sun is the closest star to Earth – 150,000,000 km away The next closest star is Proxima Centauri – 39,900,000,000,000 km away –4.2 light years Stars are extremely far away!!! The Sun is thousands of times closer to Earth than other stars The Sun Proxima Centauri

Light Years Unit of measurement for distances in Space The distance that light travels in one year. Light travels at about 300,000 km/sec. –186,000 miles/sec One light year is equal to 9.46 trillion km (9,461,000,000,000). –5.87 trillion miles (5,870,000,000,000) Light travels faster than anything else known to man.

Classifying Stars ClassColorSurface Temp. (degrees Celsius) Elements detected Examples of stars O BlueAbove 30,000Helium10 Lacertae B Blue-white10, ,000Helium and Hydrogen Rigel, Spica A Blue-white7, ,000HydrogenVega, Sirius F Yellow- white 6, ,500Hydrogen and heavier elements Canopus, Procyon G Yellow5, ,000Calcium and other metals The sun, Capella K Orange3, ,000Calcium and Molecules Arcturus, Aldebaran M RedLess than 5,000MoleculesBetelgeuse, Antares

Hertzprung–Russel (H-R) Diagram - a graph that shows the relationship between a star’s surface temperature and it’s absolute magnitude.

H-R Diagram Analyze the graph!

Analyzing the H-R Diagram Brightest Stars Y-Axis Brightness Dimmest Stars Hottest StarsX-AxisCoolest Stars Temperature

Stages of a Stars Life Cycle

Nebulas – Stellar Nurseries Giant clouds of gas and dust in space Where new stars are formed

GALAXIES Large group of stars in space held together by Gravity Classified by Shape - Sprial/Disc, Elliptical, Irregular Shaped

Spiral/Disc Shaped Galaxy Andromeda Galaxy–Large center with spiral arms traveling around it –Ex. Andromeda Galaxy and our Milky Way Galaxy –Our Sun is located near the edge of the Milky Way Galaxy

Our Milky Way Sprial/Disc Shaped Galaxy 100,000 Light Years Across Black Hole at the center The Sun is near the edge of our galaxy in one of the spiral arms.

Elliptical Galaxy M 87 Galaxy –Massive blobs of stars that have very bright centers –Very little gas and dust –Contain mostly old stars.

Irregular Galaxy Large Megellanic Cloud –Don’t fit into any other class. –Have irregular shapes –Contain mostly young stars and lots of gas

Supernova Death of a star by explosion

Black Holes Gravity is so strong not even light can escape Believed to be the center of most galaxies

Theories on the Origin of the Universe How did we get here? The Big Bang Theory – states that the universe began with a big explosion. Steady State Theory - the universe has always been here and always will. There are many more theories

The Big Bang Theory Most dominant theory States that the universe was created from a cosmic explosion that hurled matter in all directions Occurred about billion years ago

Evidence that supports the big bang Cosmic background radiation –radiation coming from all directions in space, believed to be left over from the big bang. The observable expansion of the universe (Red Shift). –Galaxies are moving away from each other

Spectroscopes/Spectrometers Used to gain information about properties of components in the Universe Shows differences in the elements that make up a star.

Electromagnetic Waves Light Waves that Astronomers can use to gain information about distances and properties of components of the universe.

Electromagnetic Waves Radio waves Microwaves Infrared waves Visible Light Ultraviolet waves X-Rays Gamma Rays Cosmic Rays

From lowest to highest frequency (energy)

Electromagnetic Waves Research 1. Look up Electromagnetic Waves using your netbook. 2. Define electromagnetic waves 3. List all the electromagnetic waves in the electromagnetic spectrum 4. Describe what each type of wave is used for by humans.