Chapter 12 Space Exploration

Section 12.1 page 428

Explaining the Early Universe

GALAXY – collection of stars, planets, gas and dust held together by gravity

SOLAR

SYSTEM

GALAXY – Milky Way

UNIVERSE

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, galaxies 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 star

Spectrum of a star moving

Towards Earth (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 “Big Crunch”

– 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 SOLAR SYSTEM

STELLAR COLLISION THEORY

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

NEBULAR HYPOTHESIS

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 on a spiral arm, we see the center on it’s side at night

Some of the oldest and largest galaxies are elliptical, more then 50% of galaxies are this shape

THE EVOLUTION OF STARS

DWARF STARS GIANT STARS

Small, burn fuel slowly, last a long time (100 billion years) red dwarfs to white dwarfs and burn out

Large, burn fuel quickly, last a short time

RED GIANTS to white dwarf to black dwarf

OR

SUPER GIANTS supernova to neutron star to black hole

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 GIANT star 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

Careers Related to Space

Engineer

Astronaut

Doctor

Scientist

Pilots

Technicians