Unit Nine - Astronomy - Galaxies & Stars

Question 1

Definition of Galaxies

Answer 1

Stars & Gases that are held together by gravity.

Question 2

What are the three shapes that Galaxies are classified by?

Answer 2

1. Irregular
2. Elliptical
3. Spiral

Question 3

Definition of Milky Way Galaxy (3)

Answer 3

1. Spiral Shaped
2. 200 billion stars
3. Our solar system

Question 4

Definition of Star (5)

Answer 4

1. Large Ball of Gas
2. Held Together by Gravity
3. Produces tremendous amounts of energy
4. Shines
5. Makes up Most of the Known Matter in the Galaxy

Question 5

Definition of Nuclear Fusion (4)

Answer 5

1. Combining of smaller elements to form nuclei or larger elements
2. Stars use this process in order to stay alive
3. Nuclear fusion releases energy and heats up the star to survive
4. If the rate of Nuclear Fusion increases, the star expands and explodes

Question 6

Definition of Luminosity

Answer 6

A measure on how bright a star us compared to the Sun
(The bigger the star, the greater the Luminosity)

Question 7

Life Cycles of Stars (4)

Answer 7

1. Clouds of dust and gases
2. Gravity causes them to clump together
3. Forms balls of dust & gases
4. After enough heat, they ignite and start nuclear fusion
   (Heat = Gravitational Contraction)

Question 8

Definition of Main Sequence Star (6)

Answer 8

1. Average size
2. Average Temperature
3. Average Luminosity
4. 90% Known Stars
5. Sun
6. Middle Aged Star

Question 9

Definition of Red Giant Stars

Answer 9

1. Star
2. Luminous
3. Late phase of stellar evolution

Question 10

Definition of Supergiant Stars

Answer 10

1. Extremely high temperatures
2. Late phase of stellar evolution

Question 11

White Dwarf Stars (3)

Answer 11

Earth sized star
Low luminosity
Hot surface