Question

You have seen that scientists use a unit called a light-year (l-y) to measure distances in space. One

light-year is equal to the distance light travels in one year. This distance is about 9.5 × 10 15 m.
Another unit, called an astronomical unit (AU), is used for smaller distances, such as distances to planets
in our solar system. One astronomical unit is equal to the distance between Earth and the sun. This
distance is about 1.5 × 10 11 m.
A third unit, called a parsec (pc), is used for distances to stars. The term parsec is based on parallax
and seconds. The seconds in parsec are not units of time. They are measurements of the angle used in
parallax to calculate the distance to a star. One parsec is equal to about 3.1 × 10 16 m.
The star Deneb has been estimated to be 1,500 l-y away from Earth. If you wanted to find out how
many meters away Deneb is, you would multiply the distance in light years by the number of meters in a
light year. To do this calculation in scientific notation, you must convert 1,500 to scientific notation.
1,500 l-y = 1.5 × 10 3 l-y Convert 1,500 to scientific notation.
(1.5 × 10 3 l-y) × (9.5 × 10 15 m/l-y) Multiply that number by the number of meters in a light year.
Next, analyze the units. Multiplying light years by meters per light year gives the unit meters, which is the
unit you are looking for.
(1.5 × 9.5) × (10 3 × 10 15 ) m Rearrange the numbers so that like numbers are grouped together.
(14) × (10 18 ) m Multiply within the parentheses.
1.4 × 10 19 m Rewrite in scientific notation.
1. Which of the three units described is the largest? How can you tell?
2. The nearest star to Earth is about 4.1 × 10 16 meters. Why is the
light-year a better unit than the astronomical unit for expressing
this distance?
3. Beta Centauris is 161 pc from Earth. How many meters is this?



PLS ANSWER ALL OF THESE QUICK LOL

Answer 1

1. Parsec

2. (in explanation)

3. 4.9 x 10 ^18 m or (5 x 10 ^18 m *rounded*)

Step-by-step explanation:

1. Parsec is the biggest unit of distance

A light year is 3.1 × 10 ^16 m.

A parsec is 3.1 × 10 ^16 m.

An Astronomical unit is 1.5 × 10 ^11 m

2. Light year is a better unit because Astronomical unit is too small of a measurement to calculate the star to earth, light year and parsec would be the most accurate to calculate the distance.

3. Beta Centauris is 161 parsec's away from earth

to calculate this multiply 161 to ( 3.1 × 10^16 m )

161 x 3.1 = 499.1

499.1 x 10 ^16 meters

bring up the exponent by moving the decimal up

4.9 x 10 ^18 m

You *could* round the answer to 5 x 10 ^18 m