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