Space Basics
Galaxies & The Universe
Stars
Brightness, Luminosity, & Gravity
Star Life Cycle
100

What is the 5th planet from the Sun?

Jupiter

100

Our galaxy is called this.

The Milky Way

100

A star is a huge ball of extremely hot gas that produces its own ______.

Light & Energy

100

This describes how bright a star appears to an observer on Earth.

Apparent Brightness

100

Stars begin their lives forming inside enormous clouds of gas and dust called these.

Stellular Nebula
200

This is the natural satellite that orbits Earth.

The Moon

200

This type of galaxy has curved arms extending outward from its center.

Spiral Galaxy

200

The color of a star gives astronomers information about this characteristic.

Temperature

200

This describes the total amount of energy a star gives off as light each second.

Luminosity

200

This is the stage when a young star begins forming from material within a nebula.

Protostar

300

This is the name for everything that exists, including all matter, energy, space, and time.

The Universe

300

This type of galaxy generally has a smooth, rounded shape and contains mostly older stars.

Elliptical Galaxy

300

Of these two stars, blue or red, this color represents the hotter star.

Blue

300

If the same flashlight is moved farther away from you, its apparent brightness will do this.

Decrease

300

This is the longest major stage of a star's life, when it produces energy by fusing hydrogen into helium.

Main Sequence

400

Put these in order from smallest to largest: universe, galaxy, solar system, planet.

planet → solar system → galaxy → universe

400

This type of galaxy does not have a clear spiral or elliptical shape.

Irregular Galaxy

400

Put these star colors in order from hottest to coolest: red, blue, yellow, white.

blue → white → yellow → red

400

As light travels farther from a source, it spreads out over this.

A Larger Area

400

A star like our Sun eventually expands into this stage after it runs out of hydrogen in its core.

Red Giant

500

Earth is part of this system, which includes the Sun and all objects that orbit it.

The Solar System

500

According to what you learned about the universe, a galaxy can contain billions of these objects.

Stars

500

A blue star is extremely far away and appears dim from Earth. This demonstrates that a star's color and its apparent brightness tell us different things. What does the color tell us?

Surface Temperature

500

A star can have high luminosity but appear dim from Earth because it is extremely ______.

Far Away

500

Massive stars can end their lives in this enormous explosion, which can leave behind a neutron star or black hole.

Supernova