Stiffer,

I dont mind constructive criticism. Regarding using light years  there are many explanation possible. My logic is

1. In our daily life we use distance  as a point of interest for example

"100 km pachi gadi ma tel halna parcha hai"
"200 km pachi ramro tham paincha lunch ko lagi "

Now what I am saying is

After travelling 0.1 light years (0.1* 10 trillion Km)  Means after travelling 1 trillion kilometer
I have used light years as distance not time ( but if you know the speed it is possible to know the time taken to travell)
 In my story  "Indicators show that we may need new engine after approximately one light year"  means they need new engine after travelling one trillion KM

Now, how much time they will take to travell one light year?  if they are travelling at the speed of light it will be one earth year, if they are travelling at double the speed of light it will be 6 earth months and if they are travelling at half the speed of light it will be two earth years.


Use of term "light year" doesnt mean that I am using them as time


Then Why I didnt use Kilometer and miles instead of light years ?

1. Kilometers and miles are  terms used by earthlings, they orignate on earth. It is not necessary that aligns also use same units to measure the distance.

2.Even the light year may have different distance for aligns.  why?


Light year is the distanc travelled by light in one earth year,  that is in 365 days. It is not necessary that  every planet revolves round  its sun in 365 days.
What if some planets completes one circle  around its sun? 
But for the aligns who came from the planet whose one year is equivalent to 400 earth days for them if they use the term "light year" it will be the distance travelled by light in 400 earth days not 365 days.

Likie subatomic particles, elemnst which are the fundamental unit in Universe light is also fundamental to this universe that is why I beleive they use distance travelled by light as a measurement of the distance and time.


I agree that my use of words "one light year’s time" and "after travelling for nine light years" might have created confusion. I should have rephrased those but at that time I was thinking "after travelling for 100 km means after approximately one hr.
regarding  your points (1)


That is one school of thought, another school of thought is earth was rather vocanic and lots of gas offing out of earths enterior and burning in the atmosphere. lots of volcanos were erupting and they were cunsuming atmospheric oxygen by burning trees etc. At that time space around earth was not that setteled so many samller asteroids were hitting earth they were also consuming oxygen. I do not know which school is right but later fitted my fiction thats why I used it.

Your point (2)
Yes many scientis say that. Many ppl question that by saying then why our atmosphere is not catching fire ? According to them at present we need continious supply of fule in order to creat fire. Once you stop supplying fuel filre slowly dies down. According to them, if the  oxygen content more than 24% then once you start fire ( in larger scale) there will be enough heat generated for for fire to continue.
here gain, I do not know which school of thought is correct but later suited to my fiction thats why I took it.

I will definitely use your comments to sharpen coming parts.