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 Doppler Effect

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 expansion

• Very High Temperatures ~ 1 billion °C• Very Rapid Expansion Open Universe – one

that will Expand foreverTheme Song Birth of a Universe T=2:50

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 ELLIPTICALOur 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

Fate of our Sun

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

The life cycle of Stars

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

Dark MatterBlack Hole SciShow

Evidence1. Electromagnetic Radiation

detected of matter being pulled into it

2. The effect of it’s gravity on the movement of nearby stars and galaxies

3. Data collected supported by computer generated models

QUASAR

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

• Brightest bodiesin our Universe

Quasar Clip