Question

one star is 3.4 light year away from the earth. what does it mean

Answer 1

Hey there!

Light year is a unit of measurement of distance involving huge distances.

Light year can be defined as the distance travelled by light in one year, in space

It is equal to 9.461 × 10^12 kilometres

★ If one star is 3.4 light years away from the earth, then distance between star and earth is 3.4* 9.461 ×10^12 kilometres

★ Then finally the distance between star and earth would be 32.1674 ×10^12 kilometres


hope helped ★

Answer 2

Hello Friend,

First, we understand what is light year.

♦ Light Year (ly) :
→ The distance travelled by light in a year is called a light year.

→Thus, light year is a unit of distance, and not of time.

→Now, speed of light in vacuum is 299792458 m/s , which can be approximated as 3×10^8 m/s

→So, we have:
Speed = 3×10^8 m/s
Time = 1 year = 365×24×60×60 seconds

(As 1 year = 365 days, 1 day = 24 hours, 1 hour = 60 min and 1 min = 60 seconds)


Now, Speed = Distance/Time
So, Distance = Speed×Time

Now, 1 ly = (3×10^8 m/s) × (1 year)

So, 1 ly = (3×10^8 m/s) × (365×24×60×60 s)

So, 1 ly ≈ 9.46 × 10^15 m

_________________________

Now, coming to your question:

The given star is 3.4 light years away from Earth.

This means that it's distance from Earth can be calculated as follows:

Distance = 3.4 ly
= 3.4 × 9.46 × 10^15 m
≈ 3.22 × 10^16 metres

Thus, the star is 3.22 × 10^16 metres away from Earth.