Astronomy: Stars, Galaxies, and the Universe Worksheet

Question 1

What is a star, and how is it different from a planet?

Accepted Answer

A star is a large ball of hot gas that produces its own light and energy. A planet does not make its own light and usually orbits a star.

Question 2

The Sun is classified as a star. Explain why the Sun is important to Earth.

Accepted Answer

The Sun is important because it provides Earth with light and heat. It also supplies the energy that supports weather, climate, and life.

Question 3

Describe one way stars can appear different from each other when viewed from Earth.

Accepted Answer

Stars can appear different in brightness, color, and size. These differences can be caused by their temperature, distance from Earth, and actual size.

Question 4

What is a galaxy?

Accepted Answer

A galaxy is a huge collection of stars, gas, dust, and other objects held together by gravity. Galaxies can contain billions of stars.

Question 5

What galaxy contains our solar system?

Accepted Answer

Our solar system is in the Milky Way galaxy. The Milky Way is a large spiral galaxy.

Question 6

Name one type of galaxy and describe its general shape.

Accepted Answer

One type of galaxy is a spiral galaxy, which has a flat disk with curved arms. Other correct examples include elliptical galaxies, which are round or oval, and irregular galaxies, which have no clear shape.

Question 7

How does gravity help form stars and galaxies?

Accepted Answer

Gravity pulls gas and dust together into clumps. Over time, this pulling can help form stars, and gravity also holds galaxies together.

Question 8

A light-year is used in astronomy. What does a light-year measure?

Accepted Answer

A light-year measures distance, not time. It is the distance light travels in one year.

Question 9

Why do astronomers often say looking far into space is also looking into the past?

Accepted Answer

Astronomers say this because light takes time to travel across space. When we see very distant objects, we are seeing the light they gave off long ago.

Question 10

What is the universe?

Accepted Answer

The universe is everything that exists, including all matter, energy, space, time, stars, planets, and galaxies. It includes all of the objects and regions we can detect and more beyond that.

Question 11

Many scientists say the universe is expanding. What does this mean?

Accepted Answer

An expanding universe means that, on a large scale, galaxies are moving farther apart over time. It does not mean every object is growing in size.

Question 12

Explain the difference between the solar system, the Milky Way galaxy, and the universe.

Accepted Answer

The solar system includes the Sun and the objects that orbit it. The Milky Way galaxy contains the solar system and billions of other stars, and the universe contains all galaxies and everything in space.

Astronomy: Stars, Galaxies, and the Universe

Astronomy: Stars, Galaxies, and the Universe

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