Asa Dotzler posted a cool photo of Orion Nebula which just happens to be 1,500 light years away and also visible to the naked eye. One light year is about 9,460,000,000,000 km making that photo 9 trillion * 1500 kilometers away. (14,190,000,000,000,000 km or 14 Quadrillion km).
If light year is defined by the distance that light can travel in one year. It would take 1,500 years to get there traveling at 1 billion km/hour.
From How Stuff Works:
Light travels at 186,000 miles per second (300,000 kilometers per second). Therefore, a light second is 186,000 miles (300,000 kilometers). A light year is the distance that light can travel in a year, or:
186,000 miles/second *
60 seconds/minute *
60 minutes/hour *
24 hours/day *
365 days/year =
5,865,696,000,000 miles/yearA light year is 5,865,696,000,000 miles (9,460,800,000,000 kilometers).