How do they calculate light-years?

Question

For example, how do they know that the Eistein Ring is “12 billion light-years” away? Why not 10 or 20? How do they arrive at that number?

In: 2

Answer 1

The speed of light = c

Distance = d

Time = t

Equation: d = c * t

Light in a vacuum travels at a velocity of about 300000 kilometers per second.

So C = 300000km

There are 31556952 seconds in a year.
So T = 31556952

Now all that needs to be done is apply our formula to find out the Distance.

300000 × 31556952 = 946708560000 kilometers