Found this, its fascinating:
The light-year is a unit of length used to express astronomical distances. It is about 9.5 trillion kilometres or 5.9 trillion miles. As defined by the International Astronomical Union, a light-year is the distance that light travels in vacuum in one Julian year. Because it includes the word "year", the term light-year is sometimes misinterpreted as a unit of time.
Which led me to this:
Yes, there are many stars in the night sky we see that don't exist right now. Light travels extremely fast, at 300 million miles per hour, but even at that speed it may take many thousands or millions of years for it to travel and reach far places. For example, light from our Sun takes 8 minutes to reach Earth.