What is Astronomical Unit (AU)?
Astronomical Units are used to find out the distance between planets and the Sun. One Astronomical Unit equals to 149,597,870 km or 93 million miles.
What are Light Years (LY)?
Light Years are used to find out the distance light travels in one year. Light years are often used to find the distance between stars in galaxies. One light year is equivalent to 9,461,000,000,000 km or 5,878,000,000,000 miles.
How and When do scientists use AU vs. LY?
Astronomical units are used more than light years because AU's are used in our solar system only and light years go beyond that. Scientists study our solar system more, resulting in using AU more than LY.
compare and contrast:
AU
-used more frequently
-measures planets from the sun -one AU= ABOUT 93 million miles |
BOTH
-used to measure distance
-relating to astronomy -measuring in space |
LY
- measures distance light travels in a year
- can go beyond our solar system -one LY= ABOUT 6 million miles |