Our Universe

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Our Universe
Billions of galaxies made up of billions of stars
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Warm-up

• What are large groups of stars in space held
  together by gravity?
• Galaxies

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Stars - Huge bright balls of gas fueled by
nuclear energy
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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.
• Gives off electromagnetic radiation.
• Light, heat and other forms of energy
• There are 100 billion stars in our own galaxy!

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The Sun Our StarThe closest star to Earth

• Medium size
• Yellow
• Main Sequence Star
• 150,000,000 Km (93 Million miles) away.
• 4.5 - 5 billion years old
• Will last about another 5 billion years
• Located near the edge of our disc shaped galaxy
  The Milky Way

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Our Sun is located near the edge of our galaxy
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Stars are very far away

• 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

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Our Own Star SystemThe Solar System

• The Sun and the Planets that orbit it

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Stars are classified by surface temperature -
color
Class Color Surface Temp. (degrees Celsius) Elements detected Examples of stars
O Blue Above 30,000 Helium 10 Lacertae
B Blue-white 10,000 - 30,000 Helium and Hydrogen Rigel, Spica
A Blue-white 7,500 - 10,000 Hydrogen Vega, Sirius
F Yellow-white 6,000 - 7,500 Hydrogen and heavier elements Canopus, Procyon
G Yellow 5,000 - 6,000 Calcium and other metals The sun, Capella
K Orange 3,500 - 5,000 Calcium and Molecules Arcturus, Aldebaran
M Red Less than 5,000 Molecules Betelgeuse,Antares
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HertzprungRussel (H-R) Diagram- a graph that
shows the relationship between a stars surface
temperature and its absolute magnitude.
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H-R DiagramAnalyze the graph!
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Analyzing the H-R Diagram

• Brightest Stars
• Y-Axis
• Brightness
• Dimmest Stars
• Hottest Stars X-Axis Coolest Stars
• Temperature

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Stages of a Stars Life Cycle
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Nebulas Stellar Nurseries

• Giant clouds of gas and dust in space
• Where new stars are formed

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SupernovaDeath of a star by explosion
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Black HolesGravity is so strong not even light
can escapeBelieved to be the center of most
galaxies
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GALAXIES

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

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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

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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.

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Elliptical Galaxy

• M 87 Galaxy

• Massive blobs of stars that have very bright
  centers
• Very little gas and dust
• Contain mostly old stars.

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Irregular Galaxy

• Large Megellanic Cloud

• Dont fit into any other class.
• Have irregular shapes
• Contain mostly young stars and lots of gas

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The Suns Planets
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CometsRocky material made of gas dust and ice
that orbit the sun
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MeteorsSpace Rocks known as shooting stars when
they enter the Earths atmosphere.Become
meteorites when they hit the Earths surface
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AsteroidsSmall rocky bodies known as minor
planetsOrbit the sun mainly between Mars and
Jupiter (asteroid belt)
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Light YearsUnit 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.

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Theories on the Origin of the UniverseHow 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

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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 13-14 billion years ago

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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 eachother

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Spectroscopes/Spectrometers

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

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Electromagnetic Waves

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

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Electromagnetic Waves

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

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From lowest to highest frequency (energy)
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Electromagnetic Waves

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