31.3 & 31.4 Flashcards
a collection of stars, dust, and gas bound together by gravity
galaxy
a large spiral galaxy that is home to Earth and the rest of our solar system, and about a trillion stars
milky way
the theory that the universe originated in a huge explosion that released all matter and energy
big bang theory
the residual microwave radiation emitted when the universe was very young
cosmic background radiation
dark matter
invisible form of matter that does not emit any detectable electromagnetic energy of its own
invisible form of energy that creates a repulsive force causing the universe to expand at a faster rate
dark energy
what are the three kinds of galaxies
spiral, irregular, and elliptical
what shape is the milky way
barred spiral
what is a local group
a larger group of galaxies which includes about 50 galaxies spread out over a distance of 10 million light years across
cosmology
study of how the universe began, how it continues to change, and what it is made of
about how many galaxies are in a local group
50
what are the two largest galaxies in our local group
milky way and andromeda
where is our solar system located in the milky way galaxy
the center of one of the spiral arms
how long ago was the big bang
13.7 billion years
