You can justify anything in terms of scientific principles if you just try hard enough. And poke around the edges enough. And come up with enough half-baked excuses about why it should actually work that way, no, really.

But the best way to get your players to accept something that, on the face if it, sounds completely absurd, is to simply present it to them as a fact and have them figure out how it works.

It's a giant floating city, hovering in the sky.
But, how is that even possible? There can't be enough magic in this world for something like that.
Oh, it's possible all right. Heh heh heh...

Technical footnote: We originally had Jim collapsing the theta coordinate. But then we realised that would just be wrong.

Transcript

Jango Fett: I'll disable his ship with another sonic mine so we can land.
{launches mine}
Obi-Wan: Sonic mine? In space?
Padmé: No, that would totally work. An explosion designed to create a rarefied atmosphere of ionised gas, through which the shock wave travels.
Padmé: It's an extremely destructive sound. The advantage is it can't be dodged.
R2-D2: Woo-hoo! Can't. Be. Dodged.
GM: Er. Actually, these ones are shaped charges that explode in a disc.
{the mine explodes, silently}
R2-D2: Oh right. Cause that's an advantage.
Padmé: Hey, yeah, it is. It focuses the blast into an inverse linear profile, rather than inverse square, which increases the range and energy density at the cost of solid angle coverage.
[SFX]: BWANGGGG!
Obi-Wan: Cool. I dodge.
Padmé: See, when you take the integral you collapse the phi coordinate...
R2-D2: Hearing this is almost worth allowing the dodge.