Without tags, would a short piece of text be enough to distinguish between an article about science and a piece of speculative fiction?
For example, here are two quotes:

(a) “… the initial leap from nothing to something may have been inevitable. Then the resulting tiny bubble of space-time could have burgeoned into a massive, busy universe…”

(b) “If the universe came to an end every time there was some uncertainty about what had happened in it, it would never have got beyond the first picosecond.”

Is it immediately clear which one is about physics and which is fiction?
As a matter of fact, one of the quotes is from a recent article in BBC, which gives a quick overview of how our universe came into being from “nothing”. Here is a longer quote from the same article:

“… a fraction of a second after the Big Bang, the quantum-sized bubble of space expanded stupendously fast. In an incredibly brief moment, it went from being smaller than the nucleus of an atom to the size of a grain of sand. When the expansion finally slowed, the force field that had powered it was transformed into the matter and energy that fill the universe today.”

If you cannot tell which quote belongs to the article, and which is to fiction, here is additional hint:
The article asks “why did it only happen once? If one space-time bubble popped into existence and inflated to form our universe, what kept other bubbles from doing the same?”

To find out how a well-known cosmologist answers the question, I suggest reading that article, titled “Why there is something rather than nothing?”.

About the quotes:
(a) is from the article.
(b) is from “Dirk Gently’s Holistic Detective Agency”, by Douglas Adams.