Chapter 31 section 3+4 Flashcards
a large group of stars, dust, and gas; held together by gravity
Galaxy
Spiral galaxy that is about 100,000 light-years in diameter and contains 200 to 400 billion stars, including the sun
Milky Way
a group of 50 galaxies including the Milky Way
Local Group
study of how the universe began, what it is made of, and how it continues to evolve
cosmology
theory that about 13.7 billion years ago, the entire universe was contained in a single point that began expanding outwards
big band theory
residual radiation from the formation of the universe, predicted by the big bang theory and later detected in 1965
cosmic background check
type of matter that cannot be seen and can only be detected by its gravitational effects
dark matter
energy that might be causing the accelerating expansion of the universe
dark energy
What are three galaxy shapes?
Ellipse, Spiral, and irregular
What shape is the Milky Way galaxy?
Spiral
How many galaxies are located in the local group?
50 galaxies
What are the two largest galaxies in the local group?
Milky Way and Andromeda
Where is our solar system located in the Milky Way?
On one of the arms
How long ago did the big bang occur?
13.7 billion years ago
What is the shift of light wave lengths is called?
Doppler effect
