Cosmology Basics
What is the scientific study of the origin, evolution, structure, and eventual fate of the universe called?
cosmology
What branch of science focuses on studying objects and phenomena beyond Earth, including stars, planets, galaxies, and other celestial objects?
Astronomy
What causes cosmic microwave background energy?
cooling as the universe expands
How old is the universe?
13.7-14 billion years old
What concept does Hubble’s Law most concern?
growing distance between galaxies
What force binds a galaxy together?
gravity
Which of the following items is the largest?
atom, universe, galaxy, solar system
universe
What theory states that the universe began in an extremely hot, dense state and has been expanding ever since?
the Big Bang Theory
A scientist knows the redshift value of a particular celestial object. What can they use this information most directly to find out?
the age and distance of the object
What is happening to the universe today?
It is expanding in size.
How would cosmologists describe the overall content of the universe?
isotropic
What is the sun?
a star
What was the universe immediately before the Big Bang occurred?
a singularity
Scientists estimate the age of the universe by studying evidence such as the expansion of the universe and the oldest stars. What does the expansion of the universe help scientists understand?
How long the universe has been expanding
Observation has shown that galaxies further away from us are moving away at a faster rate than galaxies closer to us. What does this evidence most directly support?
the Big Bang theory
Which of the following is an example of a question that could be answered using cosmological models?
who created the universe
what stars are made of
whether souls exist
if there is non-human intelligent life
what stars are made of
What is the name of the galaxy we live in?
the Milky Way
What term describes the extremely hot and dense state from which the universe began expanding?
Singularity
Why can't scientists simply use the age of Earth to determine the age of the universe?
Earth formed billions of years after the universe began, so Earth is much younger than the universe.
What does a closed universe model predict will happen after expansion stops?
The universe would begin to contract.
You take a glass jar filled with clear paint and add a few pinches of sand into it. You then use a paint mixer to vigorously shake the jar, mixing the sand uniformly in it. When the jar is held to the light, the sand is evenly distributed throughout. What is this an illustration of?
the cosmological principle
An astronomer notes that the celestial object they are observing is exhibiting a blueshift. What does this mean?
It’s moving towards the astronomer.
What observation shows that most distant galaxies are moving away from us, providing evidence that the universe is expanding?
the Redshift
Scientists observe very distant galaxies by looking at light that has traveled for billions of years. Why does this help scientists study the early universe?
Because the light shows what those galaxies looked like billions of years ago.
In a closed universe model, what is the term for the hypothetical collapse of the universe back toward an extremely dense state?
The Big Crunch