Download Studying Space

Studying Space
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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 Motion
1st law: planets move in ellipses
perihelon: closest to sun
aphelion: farthest away
Kepler’s
• Law of Equal Areas
• Planets move fastest
when they are closest
to the sun.
http://csep10.phys.utk.
edu/astr162/lect/binari
es/visual/kepleroldfra
me.html
nd
2
law
Kepler’s
rd
3
• 1 astronomical unit = the
distance from the earth to
the sun = r
• 1 year = period of
revolution = p
• For any planet:
– K r3 = p2
law of motion
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