Importance and Units
This unit equals about 150 million kilometers – the average distance from Earth to the Sun.
Astronomical Unit (AU)
This is the only celestial body other than Earth that humans have visited.
the Moon
This is the name of the galaxy Earth is in
The Milky Way
This term refers to how far we can observe in any direction in the universe
The Observable Universe
In a football field model, if the Sun were a car, Earth would be this far away.
26 metres
This unit measures how far light travels in one year
Light Year
Light from the Sun takes this long to reach Earth
8 minutes and 20 seconds
The closest star to Earth (besides the Sun)
Proxima Centauri
The observable universe is estimated to be this many light-years across
93 billion light-years
Light takes this many seconds to reach the Moon
1.3 seconds
One parsec is equal to approximately how many light-years?
3.26 light-years
Earth is this far from the Moon in kilometers
384,400 km
The Milky Way is roughly this many light-years wide
100,000–120,000 light-years
When we look far into space, we are also looking far into this
The past
Extraterrestrials
The name "parsec" comes from these two words
Parallax and arcsecond
The spacecraft that has traveled the farthest from Earth
Voyager 1
This galaxy is our nearest spiral neighbor
Andromeda
True or false: Earth is at the center of the universe
False
This type of unit would be impractical to use for measuring distances in space
Kilometres
Scientists use parsecs instead of light-years when measuring what?
Large distances between stars or galaxies
The edge of the solar system
The heliopause
Which spiral arm is Earth in?
We see as far as light has had time to reach us since this event
The Big Bang
This is how long it would take Voyager 1 to reach the nearest star, even traveling at over 60,000 km/h
70,000 years