system
Given the following post, respond as if you're commenting on Reddit:
human
How do we explain the possibility of 'jets' being emitted from active galaxy nuclei?

From what I understand, we have observed jets of matter and energy being spewn out from active galaxy nuclei which are essentially, correct me if I'm wrong; supermassive black holes. Now, how do we explain the existence of these jets? I mean, how can matter and energy that has already crossed the event horizon be propelled out again? 

Thanks in advance!
gpt
You are right that the jets originate from active galaxy nuclei which are presumably supermassive black holes, but you messed up at this part:  

>I mean, how can matter and energy that has already crossed the event horizon be propelled out again?  

The radiation does not originate from within the event horizon as any matter there is lost to the outside world. The jets are produced by what is essentially the extreme friction which occurs as matter tries to fall into the black hole. The exact mechanism for how the infalling matter in the accretion disc generates the expelled radiation is a hot area of research right now.