"No, just needs people to be able to visit for short periods safely to establish byproduct dump sites and visit them when they want to become mages."

"Okay. That'll be easier. Does byproduct have mass?"

"No. It's nothingness."

"Nothingness like vacuum, nothingness like magical annihilation juice, nothingness like something weirder?"

"It's not... juicy. It warps space, is that weirder?"

"Pretty weird! Sorry, that was an idiomatic usage of the word juice to mean energy."

"The warping space can be useful, it can make gates in controlled doses."

"Sounds useful. If, uh, possibly dangerous."

"The gates haven't hurt anybody besides small-scale if disfiguring accidents. The disappearance points in the ground are the bad news."

"Yeah, the planet those go on should be not in this star system. I wonder if falling into your star would destroy them or just eat the star."

"I would bet against the star."

"Yeah so that one needs to be not just a planet nobody's using but a star nobody's--ah. Hmm. How long has your planet been appreciably declining in mass?"

"For thousands of years we thought the disappearance points only grew when somebody used magic. It only became clear they grew on their own very recently. It accelerates as they get bigger. If you want to find us a star no one's using with several destructible planets we could easily put off the question for a long time, longer if your magic can replace the essentials of ours."

"I can do magic that arbitrary people can't learn, and so can the fairies and the angels, but there is, also, magic that anyone can learn. Actually that's where fairies come from in the first place, not that they'll usually admit it. Anyway. What I was wondering was how your mass reduction interacts with orbital mechanics--see, planets have a velocity, and the reason they don't just fall into their stars is because they're going too fast--my concern is the possibility of accidentally slingshotting reduced-mass planets out of the solar systems in question. But if it takes that long for a planet to get used up probably we can just keep an eye on that even if it does happen, which, I don't actually know if that's a risk because I'm not an orbital mechanics person. How hard is your magic system to learn? Our general-purpose one is versatile but very detail-intensive." 

"It's - not that hard but it is very dangerous. Falling unconscious is the gentlest possible failure of a spell. I am unusual in still having all my toes."

"Alarming! I have never met anyone who lost bits from doing magic. I mean I could fix it if you had lost bits, healing's easy, but. Alarming. I guess you'd get a different small subset of people deciding to be mages that way but I think I like our selection effects better."

"Oh?"

"If I had to pick, I would rather the people who had magic were people who were detail-oriented and patient than people who were risk-takers."

"- I mean, mine also requires detail-orientedness, because you only start losing extremities if you don't do the spell right."

"Well, fair enough. Just, I know a lot of people are--bad at thinking they could possibly be the person the bad thing happens to, even when the statistics are right there."

"Yeah, we lose folks that way. Uh, the main things we use magic for that people'll be very reluctant to give up are healing - doesn't work on missing toes but works well on infections - and family planning and pest control and the gates. Most other things we can probably put down if we have to."

"By 'family planning' do you mean birth control or, like, some kind of information-handling thing." 

"- our magic's purely destructive, that is the only thing it can do. So, some abortion, but also sterilization when people have had enough."

"Ah. Well, good news, we have birth control that isn't magic at all. In both permanent and non-permanent forms. Also safe abortion but that gets slightly more complicated what with the afterlife."

"- oh dear, do the babies show up?"