studying space sol version. the universe how old? -- 13.7-15 billion years old how did it begin? –...
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Studying Space
SOL version
The Universe
• How Old? -- 13.7-15 billion years old
• How did it begin? – The Big Bang Theory
Galaxy
• Groups of stars & nebulae• Our galaxy:
– Milky Way Galaxy
– Spiral
• Types:– Spiral galaxy
– Elliptical galaxy
– Irregular galaxy
The Birth of a Star
• A nebulae of gas & dust starts to condense
• Temp => 10,000,000° C• Fusion begins• 2 Hydrogens 1 Helium
Stars
• Celestial bodies made up of Hydrogen & Helium
• Groups of stars are called Constellations
• Star Clusters/Globular Clusters – 100s of stars that move as 1 mass
• Binary Stars – pairs of stars that rotate around each other.
• H-R diagram
Motion of stars
• Apparent motion tends to be circumpolar.
• There are 3 real motions– 1) rotate on an axis
– 2) revolve around another star
– 3) move to or away from the earth
Distance in space• Distance is measured in light-years• 1 light–year = 9.5 trillion km• Sun to earth = 8 light-minutes = 93 million miles = 1AU• Proxima Centauri = 4.2 light-years away
• Polaris (North Star) = 700 light-years away.
Parallax of stars• Aids scientists in measuring
distance.• It is the apparent shift of a star
over a 6 month period.• It is just like when you shut
1 eye & look at an object; then open the other & the object appears to have moved.
Our Star == SUN• 3 Regions
– Core• H + H = He
• E=mc2
– Inner zones
– Atmosphere
Sunspots
• Cooler areas of the Sun• Sunspot Cycle = 11 years• Current cycle low in 1997
HIGH to another low in 2008
Solar Flares
• Electrically charged particle are shot out into space
• Cause magnetic Storms• Disrupt satellites & ISS
Solar Wind • Flow out from the sun• Ions shoot out toward
the planets
Auroras
• Northern/Southern Lights
Solar Eclipses
Models of the Solar System
• Aristotle – Geocentric model– Earth in the middle
• Copernicus– Haliocentric model– Sun-centered– Proven by Galileo’s
telescope– Identified Retrograde motion
Kepler’s Laws of Motion1st law: planets move in ellipses
perihelon: closest to sun
aphelion: farthest away
Kepler’s 2nd law
• Law of Equal Areas• Planets move fastest
when they are closest to the sun. http://csep10.phys.utk.edu/astr162/lect/binaries/visual/kepleroldframe.html
Kepler’s 3rd law of motion
• 1 astronomical unit = the distance from the earth to the sun = r
• 1 year = period of revolution = p
• For any planet:– K r3 = p2
Newton’s use of Kepler’s Laws
• Gravity keeps the stars & planets in motion
• G = m1 x m2
d2
Asteroids
• Most stay in the Asteroid Belt between Mars & Jupiter
• Large rocks left over from the creation of our solar system
• Very similar to earth rocks– Silicates
– Iron & nickel
– Carbon
Comets
• Orbit the sun in very large ellipses
• Oort cloud: origin of most comets – located beyond Pluto
Meteroids meteors meteorites
Lunar Eclipses
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