Starkiller Base is one of the most physics breaking things in sci-fi from recent memory. I mean, nothing about it makes sense. Its beam being visible from across the galaxy, while clearly done for dramatic effect, is ludicrous. Let's just assume it was a function of it shooting through Hyper-space or something.
Also a star the size of the sun is millions of times more massive than an earth-sized planet. Syphoning a star into a tiny planet makes no sense. Are we to assume they do a direct mass to energy conversion, then when the oscillator is broken the energy converts back into mass and ignites as an absurdly small star in the place of the planet?
I know it's all fantasy and done for the sake of the narrative but Starkiller base kind of bothered me from my first viewing and its just as ridiculous on a second viewing.