Well, there's a reason it's "science fiction" and not "science fact" even beyond being a made up story. The so called science in science fiction is more often than not complete and utter bullshit itself. To be fair though, we don't even know how ether is supposed to work really, do we? So just saying "That's not how it works. That's not how any of this works" is kind of less impactful here. There's some setting specific mumbo jumbo between point a and point b for that kinetic energy to gravity bit we were talking about in here. It's not like it's an excuse or anything, just that the presence of this ether stuff kind of already threw regular science out the window from the start.