"1,500 lightyears away"... doesn't that mean that what we're seeing actually happened around 516 AD? If it is aliens, then they were much more advanced than us back then, and they would be much much more advanced than us today.
Also, I always find it slightly amusing how NASA sends electro magnetic radio waves into space to try to communicate with aliens... this is assuming that 1. Aliens want to communicate with us, and 2. other life-forms throughout space are using the same communication technology that we are.
The time frame in which humans have been actively searching space is so small, it's mind-blowing to think of how far we have to go before even understanding .01% of what's out there.