a light year isn't a measure of time, it's a measure of distance, it is the distance a photon will travel in one sidereal year. Figure 186,000 miles per second X 60 seconds x 60 minutes X 24 hours X 365.25 days = a whole shit load of miles. Apx 5.87 x 10 to the 12 power 5,870,000,000,000 or almost 6 trillion miles.
So if that little photon has been traveling for a million years, you can see why contacting a race that lived around that star has some difficulties attached to it.
and I refuse to go back and try to remember calculus and quantum mechanics for the astronomy course. I used to love watching the jocks sign up for it looking for a "gut" course.
