This is the most reasonable explanation for the flash in the sky...which is why I'm the most skeptical about it. Russia isn't governed by reason. It's the wild west with more vodka and less horses. It may sound counterintuitive, but it makes too much sense for this flash to be a meteor.
I'm a big time believer in aliens. They're definitely hiding among us on Earth, pulling tricks like killing a bunch of reindeer in Norway and making a bunch of birds fall out of the sky in Massachusetts. Occasionally they flash in the sky to freak us out, probably as a distraction while they secretly brainwash us into thinking Hillary Clinton and Donald Trump are actually acceptable presidential candidates. Don't count aliens out of this race.
RUSSIAN MISSILE TEST: 3/1
Vladimir Putin is in a constant dick measuring contest with the United States of America. He knows that we're the clubhouse leaders in nuclear weapons and the military in general. What does he do to combat this? He works constantly on creating a humongous missile to try and scare us. It would make sense that this was some misfire that accidentally shot into the sky and combusted like a firework. When you're making a giant missile, there are bound to be some mistakes here and there (read: Putin probably had the person who made the mistake sentenced to death via being thrown in a cage with a tiger).
If this were actually something I could bet on, I think I would put money on aliens. They're just enough of a long shot that you could make some bank if you're right, and it's by far the most fun story. The meteor option is so boring, and the missile option is kinda scary if we're being totally honest. Confirming that there are aliens here on Earth would be fuggin sweet, and I would make money hand over fist with those odds. Someone in Vegas, set these odds up.