Question

It is estimated that light takes 10,000 years to travel the full distance across our galaxy. If light travels at 3.0 x 10^8m in 1 second then what is the distance across the milky way? Give your answer in standard form

Answer 1

Given:
Time taken = 10,000 years
Now,
converting 10,000 years to seconds,
We have,
1 year = 365 days
= (365 * 24) hours
= (365 * 24 * 60) minutes
= (365 * 24 * 60 * 60) seconds
= 31536000 seconds
So,
Time taken = 10,000 years = (10000 * 31536000 seconds)
=
`3.1536 * 10^(11) seconds`
Also, according to the question,
speed =
`3.0* 10^(8) m`

We know,
speed = distance / time taken
speed * time taken = distance

`(3.0* 10^(8)) *3.1536 * 10^(11) = distance`

`9.4608* 10^(19) = distance`

So, the distance across the milky way is
`9.4608* 10^(19)` meters.

Answer 2

In standard form and units of my choosing, the distance is 10,000 light-years.