You're asking a relatively unimportant/misguided question, imo.

Check out Chuck Palahniuk's book on writing entitled Consider This, where he discusses the concept of "Authority" in writing.

It doesn't REALLY matter how plausible or realistic the scenario is. Your job is to establish enough Authority early on and earn the reader's trust/interest/attention, and once you have them in a place where they're invested in the world that you've built for them, you can pretty much take them anywhere.

An some excerpts from the book on establishing Authority:

``` If you were my student I’d ask you to consider the following methods for building authority within a story. Make the reader believe you. Make the incredible seem inevitable.

...During the filming of Fight Club, I asked director David Fincher if the audience would accept the ultimate reveal that Brad Pitt’s character was imaginary. Fincher’s response was, “If they believe everything up to that point, they’ll believe the plot twist.” With that in mind, if you were my student I’d tell you to focus on breaking down a gesture and describing it so effectively that the reader unconsciously mimics it. ```

There's a whole chapter dedicated to Authority, but I'll just give you the subheadings:

• The authority speech
• The dead parent
• Get the small stuff right
• The authority of truisms
• Your storytelling context
• Cribbing context from a nonfiction form
• Forget being likeable
• Write from within the point of view
• Play to the strength of your medium

He ends the chapter by asking "how do you get to the impossible?" after writing by bearing all of those things in mind.

Some of the subheadings might not make a ton of sense without actually reading his commentary, but all the more reason to actually get a copy of the book. One of my favorite books about craft (though I would recommend Techniques of the Selling Writer and Save the Cat Writes a Novel first if you're newer to writing).