Scientific evidence suggests that the universe began approximately this many years ago.

What is 13.8 billion years ago?
Our address in space can be listed as: Universe โ ________ โ Solar System โ Planet Earth.
What is the Milky Way Galaxy?
This nearby spiral galaxy is moving toward the Milky Way and is expected to eventually collide with it.
What is the Andromeda Galaxy?
Thinking on such a large scale may feel like a curse, but everything in space makes up our _______.
What is the universe?
This piece of space equipment is used to collect data and capture images of distant galaxies.

What is the Hubble Space Telescope?
This leftover heat energy from the Big Bang is detected as microwave radiation throughout the universe.
What is cosmic background radiation?
The Milky Way Galaxy is classified as this type of galaxy because of its curved arms extending from the center.
What is a spiral galaxy?
Based on the observed spectrum, this galaxy is moving in this direction relative to Earth.
What is away from Earth?
If scientists gathered to hang, they'd agree the universe began with a _______.
What is the Big Bang?
Hubbleโs Law describes the relationship between these two variables.
What are a galaxyโs distance from Earth and its recessional velocity?
This type of Doppler Effect provides evidence that the universe is expanding as galaxies move away from Earth.
What is red shift?
Astronomers use this unit of measurement to describe the vast distances between galaxies.
What is a light-year?
This diagram illustrates the change in wavelength caused by an object's motion.

What is the Doppler Effect?
We may not have rockets landing, but redshift provides evidence that our universe is _______.
What is expanding?
Hubbleโs Law shows this type of relationship between a galaxyโs distance and recessional velocity.
What is a direct (positive) relationship?
According to the Big Bang Theory, the universe began in a state described by these two conditions.
What are extremely hot and dense?
The Milky Way Galaxy measures approximately this many light-years across.
What is 100,000 light-years?
This diagram illustrates the relationship between a galaxyโs distance and its recessional velocity.

What is Hubbleโs Law?
Pictures of the Milky Way often go viral, showing its curved arms arranged in a _______.
What is a spiral?
Hubbleโs observation that more distant galaxies move away faster supports this major conclusion about the universe.
What is that the universe is expanding?
Since the Big Bang, the universe has undergone these two major changes.
What are expanding and cooling?
Within the Milky Way Galaxy, our Solar System is located approximately here in relation to the galaxyโs center and outer edge.

What is halfway from the center to the outer rim?
Based on this diagram, Galaxy A is farther from Earth than Galaxy B. This galaxy would have the greater recessional velocity.

What is Galaxy A?
Among the stars, there's so much to see, and billions of them can make up a _______.
What is a galaxy?
According to Hubbleโs Law, a galaxy moving away at a high velocity is likely located at this relative distance from Earth.
What is farther away from Earth?