Chris

That depends entirely on your frame of reference. The Bible simply assumes there is a supernatural realm and never really sets out to prove it. People of religious faith almost universally believe there is a supernatural realm, though their faith dictates precisely how they conceive of it. That may predispose us to assume such events did happen but should not lead us to absolutely conclude that they did.

So my approach to your question is different than yours. You approach it scientifically and conclude that nothing known to science could cause a disembodied hand to write a warning of future events on a wall that soon after came true. People of faith approach the story with due regard for its heritage, its genre and the intent of its authors and editors and ask, amongst other things, if it’s intended as a historical account of events, and if the things it recounts are internally consistent with the book it is found in (Daniel in this case) and in the wider collection of books we call the Bible.

I should point out that the entire Christian faith hangs on a supernatural occurrence - that Jesus really did get executed by hanging him on a Roman cross until he was dead, and that on the third day after they nailed him up, he rose from the dead. On that basis you shouldn’t be surprised that Christians tend to believe not everything can be known via the scientific method (which was devised by a monk incidentally)

However, we are several light years off topic so perhaps best let it rest there.