Astronomical Unit

A light year is the 

• distance that light travels in one year
• Speed at which light travels 

What is a galaxy?

• A large storm of comets. 
• A parallel universe that existed before the Big Bang. 
• A collection of stars, dust, and gas bound together by gravity 
• Unknown 

A good way to practice parallax is with your

• Foot
• Thumb

The apparent shift in the position of an object when viewed from different locations is called 

• Parallelogram 
• Parallax 

The average distance between the earth and the sun is the 

• astronomical unit 
• Light year

Who first discovered the size of Earth?

• Romans
• Greeks

A parsec is

• angle of a star's shift over the course of a year
• the smallest unit for time

We can use brightness of stars to measure distance because

• the strength of light decrease by the square of the distance
• light is a constant and always is bright