1) It also includes minor races and nonplayer races that you have met. That's how you can be first in one tab but actually be seventh overall in the game.

2) It also can mean the game is over. But, mostly, it just means what the previous answer said.

1) don't worry too much about those ratings. military issues dominate the overall rating tho so keep that in mind. notice that littly colored strip on the left side of your readouts? just between the graph and your current research info. that is how powerful each civ is judged to be. that is what you want to keep an eye on. if you have the largest portion you don't need to worry too much about being attacked. it can happen, but you won't be surprised by an attack out of the blue. next time you buy some attack ships notice what happens in that bar. when attack ships first start being built notice what happens in the bar.

2) green button means all your ships not in orbit have moved or have standing move orders. game thinks you are ready to end the turn.

3)standing move orders are always executed at the end of turn(when you hit turn button). the turn is not actually over tho. if you have the setting that allows you to manually finish partial automatic moves you can, well, manually finish partial moves. you can also adjust other things, like research, or do diplomatic things before you finish the ship moves. if you don't have that set your ships automove then throw away spare movement points, end of turn.