Mrs. Kettering 8 th Grade Science 2011. There is a lot of controversy over the age of our universe...
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Mrs. Kettering Mrs. Kettering 8 8 th th Grade Science Grade Science 2011 2011
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Transcript of Mrs. Kettering 8 th Grade Science 2011. There is a lot of controversy over the age of our universe...
Mrs. KetteringMrs. Kettering
88thth Grade Science Grade Science
20112011
• There is a lot of controversy over the There is a lot of controversy over the age of our universeage of our universe
• The most recent information came in The most recent information came in April of 2007. From this study, the April of 2007. From this study, the age of the universe is most likely 15-age of the universe is most likely 15-20 billion years. 20 billion years.
• Keep in mind that as technology and Keep in mind that as technology and our understanding of the universe our understanding of the universe expands, that estimate may change. expands, that estimate may change.
Theory #1: Big Bang TheoryTheory #1: Big Bang Theory• States that everything began together at a point and a big explosion occurred that caused everything to move apart.
• Theory states that Theory states that galaxies are rapidly moving apart to this day
• Therefore, Therefore, universe is ever-expanding
Theory #2: Red ShiftTheory #2: Red Shift• The spectrum of a star (or galaxy)
reveals whether is it moving toward or away from the Earth
• If absorption lines are shifted If absorption lines are shifted slightly toward one end of the slightly toward one end of the spectrum, it is an indication that the spectrum, it is an indication that the galaxy is moving relative to Earth. galaxy is moving relative to Earth.
Theory #2: Red ShiftTheory #2: Red Shift• Light reaching us from distant galaxies has
its absorption lines shifted toward the red end of the spectrum which is referred to as the Red Shift – this means the galaxies are moving away from Earth
• If the absorption lines were shifted toward If the absorption lines were shifted toward the violet end of the spectrum (which there the violet end of the spectrum (which there is currently NO evidence of), the galaxy is currently NO evidence of), the galaxy would be moving toward uswould be moving toward us
This image shows the shift on the spectrum as the galaxy is moving further away
Theory #3: Oscillating TheoryTheory #3: Oscillating Theory• Combines the Big Bang and Big
Crunch theories (Red and Blue Shift Theories)
• The universe will expand until it cannot expand any more (Big Bang) and will then begin to contract (Big Crunch) … this will lead to another Big Bang and another universe.
• The top image The top image shows a shows a galaxy that is galaxy that is NOT moving NOT moving relative to relative to Earth.Earth.
• The middle The middle image shows image shows a galaxy a galaxy moving AWAY moving AWAY from Earthfrom Earth
• The bottom The bottom image shows image shows a galaxy a galaxy moving moving TOWARD TOWARD Earth. Earth.
Notice the shift on the spectrum for each possibility
Theory #4: Steady-StateTheory #4: Steady-State• States that although the universe is expanding, the amount of matter is continuously increasing as well
• Therefore, Therefore, the average density of matter is staying relatively steady, and the look of the universe does not change
• Galaxy – an organized system of hundreds of millions to thousands of billions of stars, sometimes mixed with interstellar gas and dust.
• Our Sun and Solar System are part of the Milky Way Galaxy
• Galaxies often appear to be distinct but fuzzy patches of light
• In the 1920s, Edwin In the 1920s, Edwin Hubble devised a Hubble devised a classification of galaxies:classification of galaxies:
1.1.Disc-shaped Galaxies Disc-shaped Galaxies
2.2.Elliptical GalaxiesElliptical Galaxies
3.3.Irregular GalaxiesIrregular Galaxies
• Disc-shaped (Spiral) Galaxy: flat disks that look like a spiral, with long arms winding toward a bright bulge at the center
• About 77% of the observed About 77% of the observed galaxies in the universe are disc-galaxies in the universe are disc-shaped galaxiesshaped galaxies
• Milky Way Galaxy (our galaxy) is a disc-shaped galaxy
• Elliptical Galaxy: have an ellipsoidal shape and a smooth, nearly featureless brightness profile
• Very little interstellar Very little interstellar matter (gas or dust)matter (gas or dust)
• No prominent internal No prominent internal structurestructure
• Irregular Galaxy: not disk-like or ellipsoidal and have no nucleus; chaotic, irregular appearance
• They have little symmetry in their They have little symmetry in their shapeshape
• Most irregular galaxies were once spiral Most irregular galaxies were once spiral or elliptical galaxies that have been or elliptical galaxies that have been distorted and deformed by gravitational distorted and deformed by gravitational action from other, nearby galaxiesaction from other, nearby galaxies
Sun• closest star to Earth – the next closest
star is 39,900,000,000,000 km away (4.2 light yrs)
• 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
Important Space Vocabulary:• 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 planetsOrbit the sun mainly between Mars and Jupiter (asteroid belt)
Stars• Gigantic spheres of gas 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!
Classifying StarsClass 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
Hertzsprung-Russell DiagramsHertzsprung-Russell Diagrams
• Shows the relationship between a star’s surface temperature and absolute magnitude/luminosity (brightness)
• Used to study the lives of stars–Most stars lie along the main
sequence portion of the diagram
HR-Diagram
HR-Diagram
HR-Diagram
Stages of a Stars Life Cycle
Important Star Vocabulary• Nebulae - Giant clouds of gas and dust in space.
Where new stars are formed.• Supernova gigantic explosion in which a
massive star collapses – Occurs after a massive star uses up its fuel
source• Black Hole an object that is so massive that
light cannot escape its gravity– Believed to be the center of most
galaxies– Remnants of a supernova– Astronomers can detect black holes by using X-
ray telescopes
Light Years• Unit of measurement for distancesdistances
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.
GALAXY FOLDABLE• Read Pages 720-721 and/or use your notes
to complete the following
Galaxy Type 1•Description•Example
Galaxy Type 2•Description•Example
Galaxy Type 3•Description•Example
Picture representation of Galaxy
Picture representation of Galaxy
Picture representation of Galaxy
