Light speed is 186,000 miles per second.
A Light year is how many miles are traveled in 1 year, at light speed.
So quick math for reference; If Aliens are 80 light years away, looking at earth and seeing WWII, 80 years ago. They would be; 186,000 miles per second x 60 seconds = 11,160,000 miles per minute.
11,160,000 miles per minute x 60 minutes per hour = 669,600,000 miles per hour.
There are 8,760 hours in 1 year, so 669,600,000 x 8,760 hours = 5,865,696,000,000 miles. (1 light year traveled at light speed)
1 light year (5,865,696,000,000 miles) x 80 years = 469,255,680,000,000 miles.
So, those Aliens are 469,255,680,000,000 miles away. Which isn’t really that far, only 80 light years.