Obviously I am being completely sarcastic. The point here is that the line of thinking that led you to "dome" is that it recycles or retains stuff. So by your own logic, it doesn't have to be a dome, it just has to be able to do the job you prerequisite. By no means is the atmosphere a dome in the literal sense like an ice dome would be or like the roof of a stadium but that isn't what you require. We just need something that can accomplish this task and the atmosphere does just that.
You might never get your head around it , unless you have a critical look at the model you have been brought up to accept.
That's not a dig, because I used to just accept it, before I decided to have a critical look at it and found it to be so pathetic that I just sat back and laughed at the thought that they have suckered us all.
Saying "I am right because I looked at it critically and you are indoctrinated" is not an argument. I look at it critically bud. Please do not make implications that you are above anyone cause you most certainly are far from that. Make a real argument for once, trying making some damn sense.
I'm above no one but I play you people how you try and play me.
The thing is..tit for tat gets boring and counter productive, so I use the sin bin mentality...basically I stick people like you in it when you start getting above yourselves. 
Nobody is trying to play you scepti. We genuinely think your balls off the wall insane. You deserve all the ridicule you feel.
Honestly I'm just trying to get their point of view. I highly doubt anything would convince me to a flat earth. Honestly though if you think about it, if the earth was flat, that would mean everything we know about science is wrong. And I mean everything. And we all have done science experiments and I've yet done one witch did not work. Also flat earth has a major lighting problem. I think a lot of them don't understand how light works or there might be extra light sources. The only reason we see anything is because of light. In flat earth all the side and the moon is getting 0 light from underneath so that causes moon and horizon issues.
Not to mention
-Volcano
-Thermal Activity
-Tornado, hurricane..
-Wind
-Time
-Days, season, year(Flat earth model would not match current data, then other people can out with all these other crazy models)
And the entire universe....