Is it "possible"? Sure, is it possible that the earth is flat?
Let us at least realize the distinctions between what is "possible", and what is "most likely"
Indeed, most of all matter is, at its most basic elements...IS empty space. WE haven't even touched upon the conundrums afforded by "dark matter" and "dark energy" yet...
..not that they can not be measured or "seen", but because they remain unexplained as to the "what" they comprise or are "made of", per se.Hence the terminology utilized as "something" being "dark"
However, and this is important..."ghosts" do NOT offer science any measures from which to discern anything of value. NOTHING.
And, for what this is worth, such rationales border on "conspiracy theories" that offer no evidences of any value, but a never ending series of..."Well, ok, you can debunk that, but now what about
this "possibility"? Ad infinitum.
There remains conjecture and wild speculation about "things" (ill or non-defined) that may be "possible" vs. "things" that are deterministically defined over years of independent research, discovery, and revelation...to conclude what is "most likely" to be true, or even "fact".
"Possible" should not, nor ever be conflated or construed as ,"probable" in the same context.