1. Origin of our Universe:
Life of Stars

2. OUTCOME QUESTION(S): S1-4-08: Vocabulary & Concepts
What objects make up our solar system and Universe?
Vocabulary & Concepts 
Core Fusion Nebula Supernova
Black hole Galaxy

3. Our Sun
5 billion year old small star (should last 5 more)
Composed of 75% hydrogen and 25% helium
Elements in plasma phase (hotter state than gas)
Energy comes from a Nuclear Fusion Reaction

4. Nuclear Fusion Reaction Joining two hydrogen to create helium
Releases large amount of energy
Fusion = join
Fission = split
Sun: joining (fusion) things to release energy
Power Plants: splitting (fission) things to release energy

5. There is obviously more to the Sun then “burning ball of gas”

6. Core – centre and site of nuclear fusion Outside
Layers of the Sun:
Inside
Core – centre and site of nuclear fusion
Outside
Photosphere – cooler surface (5500 oC)
sunspots, surface storms – the part we “see”
Chromosphere – inner atmosphere
small solar explosions (flares), large (prominences)
Corona – outer atmosphere (1 million oC)
charged gas particles blow outward (solar winds)

7. “Life Cycle” of a Star
Birth: Stars born out of Nebulae
Nebula – huge clouds of dust and gas
Youth – Middle Age:
Gravity collapses material into a star that begins to release energy as a main sequence (MS) star
Scientists categorize MS stars according to mass:
Small - last longer (billions of years)
Large - brighter but short-lived (few million yrs)

8. Attracted by gravity; matter clusters together
Nebula
99% hydrogen and helium
1% iron, rock and ice
Attracted by gravity; matter clusters together

9. Actually nebulae captured by NASA space telescopes

10. We can’t see most Red Dwarf stars – their light is too weak
Small MS star – Red Dwarf
Very cool temperatures of their outer gases
Death:
Forms a cool, dim star called a White Dwarf
Fades out until it no longer emits light energy
We can’t see most Red Dwarf stars – their light is too weak

11. Medium MS star – like the Sun Separated into small-med and large-med
Death:
Runs out of elements for fusion reaction
Collapses then swells to produce a Red Giant
small-med eventually fades out as white dwarf
large-med explodes as a Supernova leaving
behind a Neutron star
“Pulsar” neutron star

12. Extreme energy produced for a short period
Large MS star
Extreme energy produced for a short period
Fuses heavier elements (iron) after lighter ones
Death:
Collapses then swells to a Red Supergiant
Gravity collapses the largest into a Black Hole
Stars are in balance: nuclear fusion explodes outwards, large gravitational force collapses inwards
When the reactor runs out of elements to fuse, gravity wins and the star collapses and (sometimes) explodes

13. There is still more to this puzzle, but…this is close enough
Birth:
Nebulae
Smallest
main sequence (MS) star
Largest
Medium
Red Dwarf
Red Giant
Red Supergiant
Supernova
Death:
White Dwarf
Neutron star
Black Hole
There is still more to this puzzle, but…this is close enough

14. What do you notice?

15. Galaxies
Huge collections of gas, dust and billions of stars and planets (collected by gravity)
Constantly in motion
Many shapes: spiral, elliptical, and irregular

16. Contains 400 billion stars
Milky Way Galaxy
Contains 400 billion stars
Disc-shaped, with spiral arms – spiral galaxy
We are on one of the arms
Has a thicker Central Bulge
Rotates around the bulge
New evidence suggests the “central bulge” is actually a SUPER-MASSIVE BLACK HOLE!

17. CAN YOU ANSWER THESE QUESTIONS? S1-4-08:
How do star create energy?
What objects make up our solar system and Universe?
Vocabulary & Concepts 
Core Fusion Nebula Supernova
Black hole Galaxy