Big Bang Basics
Cosmic Evidence
Redshift & Expansion
Universe Timeline
Data & Models
100
What does the Big Bang theory describe?
The origin of the universe and how it has been expanding over time.
100
What does CMBR stand for?
Cosmic Microwave Background Radiation.
100
The redshift of galaxies tells scientists the universe is ___________.
Expanding
100
True or False: The universe is about 4.6 billion years old.
False (that’s Earth’s age — the universe is 13.8 billion years old).
200
About how old is the universe?
About 13.8 billion years old.
200
What does the cosmic microwave background radiation represent?
Leftover heat from the Big Bang.
200
If light from a galaxy is shifted toward the red end of the spectrum, what does that mean?
The galaxy is moving away from us.
200
The universe is about how many years old?
13.8 billion years (accept 13–14 billion).
200
A galaxy is moving away from Earth. What will its light look like?
Redshifted.
300
Why is the Big Bang called a “theory” if scientists accept it?
Because in science, a theory is a well-supported explanation backed by evidence, not just a guess.
300
Which is the best evidence for the Big Bang: earthquakes, sunspots, or redshift + CMBR?
Redshift + CMBR
300
Place in order: galaxies formed, Big Bang, Earth formed.
Big Bang → galaxies formed → Earth formed.
300
Why are diagrams important for explaining the Big Bang?
They visually show expansion over time, making the concept easier to understand.
400
Describe what the universe was like at the very beginning.
Extremely hot, dense, and tiny — all matter and energy were in one point before expansion.
400
How does CMBR support the Big Bang theory?
It shows faint heat left over from when the universe was young and hot, just as the theory predicts.
400
Explain how redshift is used as evidence for the Big Bang theory.
It shows galaxies are moving away, meaning the universe started small and has been expanding ever since.
400
Using Hubble’s data, explain how galaxies’ motions support expansion.
The farther away a galaxy is, the faster it’s moving away — showing universal expansion.
500
Create a simple model (drawing or description) that shows the Big Bang and expansion.
500
Explain why both redshift and CMBR together make a stronger case than one alone.
Redshift shows expansion, while CMBR shows leftover heat; together they confirm both motion and origin.
500
Describe what a blueshift would indicate and why we don’t see it much in galaxies.
Blueshift = an object moving toward us; rare because most galaxies are moving away due to expansion.
500
Explain why scientists know the universe must be older than Earth.
Earth formed inside the universe, so the universe had to exist first.