1. The Universe
Science 8

2. Components of the Universe The universe is all of space and the matter that space contains.
The universe is made up of Galaxies, Nebulae, and Stars.
Nebulae
Large clouds of gas and dust that contract under the force of gravity, ignite, and form stars.

3. Components of the Universe The universe is all of space and the matter that space contains.
The universe is made up of Galaxies, Nebulae, and Stars.
Stars
Larger spheres of gas that release light and energy through fusion reactions.

4. Components of the Universe The universe is all of space and the matter that space contains.
The universe is made up of Galaxies, Nebulae, and Stars.
Galaxies
Large groups of stars and their planets that are classified by shape:
Elliptical – Oval shaped (football)
Spiral – Bulge in the middle with arms, pinwheel-like (Milky Way)
Irregular – No definite shape

5. Classification of Stars
Size
Super Giants – solar units
Giants – 100 – 10 solar units
Medium sized – like our sun
White Dwarfs – the size of Earth of less
Neutron Star – km in diameter

6. Classification of Stars
Composition
Determined by using a spectroscope
Emission Spectrum/Absorption lines
Most common elements are Hydrogen and Helium

7. Classification of Stars
Surface Temperature
Related to stars color
Red – cooler
Yellow – Average (our Sun)
Blue/white – hot

8. Classification of Stars
Why do some stars look brighter than others?
Can a star that is farther away look brighter than a star that is closer to Earth? How?
Brightness
Luminosity – the measure of light given off
Absolute Magnitude – the total amount of light given off by a star
Apparent Magnitude – how bright a star looks from Earth

9. Classification of Stars
H-R Diagram
Hertzsprung – Russell Diagram graphs the relationship between absolute magnitude and surface temperature.

10. Types of Stars
Main Sequence Stars
A star like our sun with average luminosity (brightness) and surface temperature.
Our Sun

11. Red Giant Upper right hand corner of the H-R Diagram
Types of Stars
Red Giant
Upper right hand corner of the H-R Diagram
Bright because of their size (apparent magnitude)
Very cool temperature

12. Neutron Star Super dense core left after a supernova
Types of Stars
Neutron Star
Super dense core left after a supernova
1 tsp = 1 billion metric tons

13. White Dwarf Tiny, white hot core left from a star Very old
Types of Stars
White Dwarf
Tiny, white hot core left from a star
Very old

14. Planetary Nebulae Types of Stars
Expanding outer shell of a Sun-like star.
Contains mostly H and He, but has some heavier elements in the core
Eventually expands out into the universe and becomes available to make new stars (the universe’s way of recycling)

15. Supernova Types of Stars
A star’s iron core that reaches 1.4X the mass of our sun, so that gravity becomes strong enough to combine protons and electrons into neutrons
The core collapses into a single nucleus
The rest of the star rushes in and then bounces off the nucleus with huge force causing a spectacular explosion.

16. Life Cycle of a Star Neutron Star Black Hole Supernova SuperGiant
Nebulae to
protostar
Main Sequence
Red Giant
Planetary Nebulae
White Dwarf