Look at that again.
Plants… The stars are plants, it says. *facepalm* This has to be just a typo. It has to be, even though it appears twice in a single sentence.
There’s a grammatical error, too. Change have to has.
The stars are actually, indeed, other plants that we can see only because everyone on those planets has their lights on.
I think either actually or indeed should be deleted (and maybe both of ’em), depending on what the writer wants to emphasize. At any rate, using both is redundant.
That takes care of the spelling and grammar. Now for the science…
(If you don’t see that the “science” is wonky here… Well, there’s nothing I can do to help you. Sorry.)
There is no frakkin’ way we’d be able to see lights from any planet other than, maybe, Mars or Venus. One of our closest stellar neighbors, Alpha Centauri B, is a near-twin of our own sun, and yet its light is very dim at this distance. To be even as visible as Alpha Centauri B, the city lights or whatever on these “plants” (*rolls eyes*) would have to be as bright as Alpha Centauri B, right? Imagine city lights being that intense and yet somehow not killing everyone on the “plant”… Ridiculous, yes?
As a fun (I suppose) thought exercise/writing prompt, this one is okay (aside from the bad grammar and spelling), but if I were reading a novel marked as science fiction and happened to see something like this nonsense in the story, I’d (metaphorically, of course) throw the book across the room and then write a bloggish tirade about how badly written it is. Readers are usually willing to suspend disbelief and accept some pretty bizarre things, as long as they’re given sufficient clues that the story’s world isn’t supposed to be like their own. Don’t give them those clues, and they’ll be justifiably outraged when you ask them to accept nonsense.