The Battle Dome...this is a place where you can truely test your fighting skills

In it you get put into a Tournement with 16 people and have to progress through Quarter Finals, Semi Finals and the Finals and become an overall Champion
When you enter the Dome, you get into a big registration room, probably offering Single Battles, Double Battles and allowing you to heal your Pokémon
You then pick your team of 3 to battle with.
Once Done, you get taken to a lift.
You battle in an actual arena and battle Pokémon. It is not known what level they are at or what Pokémon there are.
Before Battling your opponent, you get some info on them and some of their Pokémon...which show some Pokémon that were not in Ruby or Sapphire before! This is a screenshot of Athlete Jubei and his Linoone, Zangoose and Porygon

Here are the rules: No Legendaries Lv. 50 or Any Level 1 on 1 or 2 on 2 The Level in Any Level matches your top Pokémon Level Difficult Increases as you go You have 4 Matches to win before Winning

At the end of your 5 Consecutive Wins in Tournements (A Total of 19 Battles) (1 on 1 Only) you get challenged by the Dome Leader. Beat him and you shall get the Silver Battle Dome Badge:

Dome Superstar Tucker	Swampert	Salamence	Charizard

At the end of your 10 Consecutive Wins in Tournements (A Total of 39 Battles) (1 on 1 Only) you get challenged by the Dome Leader. Beat him and you shall get the Gold Battle Dome Badge:

Dome Superstar Tucker	Swampert	Latias	Metagross