3&4 section Flashcards
galaxy
a large group of stars, dust, and gas held together by gravity
milky way
our solar system, including our only star- the sun- is part of a larger group of stars, dust, and gas
local group
the milky way is part of a larger group of galaxies
cosmology
the study of how the universe began, how is continues to change, and what it is made of
big bang theory
all mater and energy in the universe were compressed into a single point, which began to expand outward about 13.7 billion years ago.
cosmic background radiation
the residual microwave radiation emitted when the universe was very young
dark matter
an invisible form of matter that does not emit any detectable electromagnetic energy of its own
dark energy
an invisible form of energy that creates a repulsive force causing the universe to expand at a faster rate
what are the three galaxy shape
spiral, elips, regular
what shape is the milky way galaxy
spiral
about how many galaxy are located in the local group
50
how long ago did the big bang occur
about 13.7 billion years ago
what is the shift of light wave length called
Doppler effect
what is the universe made up of
regular matter and dark matter
