Yeah it were aliens man, the're watching you! Maybe they'll even capture you, and make strange, unpleasant things with you
Seriously though, don't rule out the possibility that those lights might have been connected to an extraterrstrial activity. There've been so many cases of people seeing unidentified objects and subjects that it certainly makes you think if you read about it. Just because it's something that doesn't happen daily doesn't mean yet that it's not possible to happen.
Sometimes though there is lightning without any sound of thunder arriving, which usually means that it's very far away and not a very strong discharge. In the night it's still bright enough though to light everything up brightly even from that far away.