Galaxy

• A collection of stars, gas, and dust held together by gravity
• Classified (grouped) by shape (spiral, barred spiral, elliptical, irregular)

Our Galaxy

• Called "The Milky Way Galaxy"

• a barred-spiral shape

Apparent Magnitude

•   the brightness of a star as seen from Earth

Absolute Magnitude

the brightness a star actually has if seen from a set distance from Earth

Life Cycle of a Star

1. Nebula - cloud of ingredients
2. Main Sequence - birth of a star, long stage
3. Red Giant - short stage
4. White Dwarf - slowly cooling

Nebula

• NEBULA, main sequence, red giant, white dwarf
• Cloud of dust and gas (building blocks)

• Ingredients needed to make stars

Main Sequence Stars

• Nebula, MAIN SEQUENCE, red giant, white dwarf
• Yellow, medium size, medium temperature, medium brightness
• Longest life stage
• The Sun is in this stage

Red Giant

• Nebula, Main Sequence, RED GIANT, white dwarf
• Red, cool, BIG (giant), bright
• Short life stage

White Dwarfs

• Nebula, Main Sequence, red giant, WHITE DWARF
• white, hot, small, dim
• Cooling over time

Fusion

• How stars generate energy
• Fuse = put together
• Put light elements (building blocks) together to make heavier elements (building blocks)