Section 4 Ch31 Flashcards
Cosmology
The study of how the universe began,how it continoues to change, and what it is made of is called cosmology.
Big bang theory
all matter 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
is the residual microwave radiation emitted when the universe was very young.
Dark matter
is an invisible form of matter that does not emit any detectable electromagnetic energy of its own
Dark energy
is an invisible form of energy that creates a repulsive force causing the universe to expand at a faster rate.
Galaxy
is 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 called the Milky way galaxy
Local Group
fifty galaxies spread out over a distance of 10 million light-years across
large group of stars
by dust, rocks
our galaxy location
Milky Way Galaxy
spiral galaxies
they rang in size from 20,000 to 200,000 light-years across.
Elliptical
spiral
Irregualur
no spiral
How many galaxies are in the local group?
about 50
What are the the two largest galaxies?
The Andoramata and Milky way
