Chapter 12 Section 12.1 page 428 Explaining the Early

GALAXY – collection of , , gas and dust held together by

UNIVERSE

GALAXY –

SOLAR SYSTEM Measuring Distances in Our Universe

• Distances within our Universe are measured in light years 1 light year = distance light will travel in 1 year = 9.5 trillion km

Speed of light = 300, 000 km/s Hubble’s Proposal

• The Universe is expanding, are moving away from each other

• The further away the Galaxy, the faster it is moving Evidence – Red Shift Analysis

• Based upon Electromagnetic Radiation (waves) • A spectroscope allows astronomers to view patterns of different stars, thus astronomers can identify and determine patterns of stars Red Shift!

Spectrum of a non-moving

Spectrum of a star moving Towards (waves contract as the object moves closer)

Spectrum of a star moving Away from Earth (waves expand as a distance increases) THEORIES OF THE ORIGIN OF THE UNIVERSE THE BIG BANG THEORY

• Since there is evidence that our Universe is Expanding, it must have started somewhere! • ~13.7 billion years ago there was a massive explosion • Very High Temperatures ~ 1 billion °C • Very Rapid Expansion Open Universe – one that will Expand forever Big Bang Timeline THE OSCILLATING THEORY

• Closed Universe – one that will Expand so far and then drawn back by gravitational forces, all the matter will meet again in a “” – This theory says the Universe goes through a series of bangs and crunches in an ongoing cycle – Currently still expanding from the most recent explosion THEORIES OF THE ORIGIN OF THE STELLAR COLLISION THEORY

• This Theory says that Our Solar System was created from the spin off of colliding stars!

Nebulae(Nebula)-H2 gas and dust between stars - When pulled together by gravity, stars form if hot enough - A nearby exploding star could have caused a shock wave which started the process -Starts to rotate as it collapses Section 12.2 Galaxies and Stars

SPIRAL ELLIPITICAL Our Milky Way Galaxy, Earth is Some of the oldest and largest on a spiral arm, we see the galaxies are elliptical, more center on it’s side at night then 50% of galaxies are this shape THE EVOLUTION OF STARS

DWARF STARS GIANT STARS Large, burn fuel quickly, last a short time Small, burn fuel slowly, last a long time (100 billion years) red RED GIANTS to to dwarfs to white dwarfs and burn out OR

SUPER GIANTS to to

BLACK HOLE

• Sphere of extremely dense material with a gravitational pull so strong not even light can pass out of it! • Created when a SUPER collapses in on itself QUASAR

• Region of extremely high energy which develops around a supermassive black hole as matter is attracted into itself The Future of Space Exploration

Pilots Technicians Engineer

Careers Related to Space

Astronaut Scientist

Doctor