chapter 9 space

• the galaxy we live in
• part of local group

a group of stars, gas, dust and planets that are held together by gravity

• cluster of stars that are between 10-1 000 000 stars
• globular and open

• group of galaxies that the milky way inhabits\
• 40 million light years across

• a star cluster between 50-5000 stars
• shapeless
• loosely held together by gravity

a spherical group of 5000-1000000 stars that is very tightly held together by gravity

a cluster of groups of galaxies that is billions of light years across

• spiral
• elliptical
• irregular

• study of the universe and its history
• different from astronomy

the effect giant planets have on the light of a faraway star

• going towards
• light is less tightly packed

• moving towards
• light is closer causing increase in frequency

the theory that there was nothing, then there was the big bang, then there was the universe

• Cosmic microwave background radiation
• leftovers from big bang

• matter that only interacts with visible matter with gravity
• 6x as much dark as other matter

• anti-gravity
• 73% of universe
• causing the expansion of the universe