Meteor in Chelyabinsk?

Quick edit: First video was deleted by the user, so I added a new first video from RT, which is a collection of different videos from different people of the event.  Incredible footage.

For some reason, I have not seen it on American "news" TV shows.








More videos and a very limited explanation:

Explosions in Chelyabinsk; Meteor Suspected

More videos linked, from a reddit post:

reddit post

Amazing footage from multiple sources.

Also, this is the building impacted showing a big hole and another building with broken windows from the shock of the impact:

Last video; note how it gets very bright and then very dark.

I have no idea why it would get so dark - light, yes, a comet streaking across the sky and impacting, but why the darkness?

Was it just an effect on the lens from the extreme brightness?