Yes that's it. >>38626898
It's a rough estimate based on general distance we see from within the game. >>38626908
All of this is shown within USUM and/or directly told to us. Necrozma is not as powerful or as special as people actually think it is. Just because it has the ability to jump through wormholes does not make it powerful as many Pokemon have this capability, as do Humans. It actually doesn't accomplish feats that stand out by comparison to the other lore and feats that we do know within the series. It's greatest feat is the ability to absorb light and shroud a world in darkness, and even then that can be reversed, again as the games show and tell us.
If you'd like to have a proper discussion on Necrozma, then please do so and act like a proper adult with an actual functioning thought in your head, otherwise cease the buzzwords. The legendaries are not all that special in any game, the only one we know for sure is a clear danger with absolute power is Arceus, and even that is nothing more than a legend.