The previews etymology is wrong. This is the right one:
"dis": in Hellenics doesn't mean bad....
"dys"="bad" (examples: ΔΥΣ-ΟΙΩΝΟ=bad-omen, ΔΥΣ-ΑΝΑΛΟΓΟ=bad-analogy, ΔΥΣ-ΘΕΟΡΑΤΟ=badly-huge, etc)
"dis": It comes from the number 2=ΔΥΟ; Hellenics: "DIS=ΔΙΣ=TWO TIMES" or DOUBLE(=ΔΙΠΛΟ).
So, disaster, is the "DIS+ΑΣΤΗΡ"="DIS-ASTER"="DOUBLE-STAR".
Two stars together AT THE SAME TIME, something unusual CLOSE TO EARTH, that causes tremendous (hel. δραματικές) catastrophes (hel. καταστροφές). It was known among ages, that this happens occasionally and the one of these two stars was the Sun; guess the other one...
Who ever knows to speak Hellenics, this is the right etymology (hel. ετυμολογία). I provide evidence, not just theories.
The truth is hidden & this is not the main one...
Μore evidence of DIS=TWO or DOUBLE (in english): distichiasis, distichon, distigmatic, disyllavism, dissyllable, ditheism, dithematic, dithyramp, dithyrous, ditokous
Μore evidence of DYS=BAD (in english): dyschromatopsia, dyschylia, dysentery, dyslexia, dysmorphia, dysodia, dyspepsia, dyspnea (& a lot more, almost all medical which expresses dys-functionality [dysfunction=BAD function]).
By all of you (dictionaries included), shouldn't be "disaster", but "dysaster"
"Hellenics"="Logic"="Mathematics" (ΕΛΛΗΝΙΚΗ ΓΛΩΣΣΑ=ΛΟΓΙΚΗ=ΜΑΘΗΜΑΤΙΚΑ).
Whether you like it or not my good friends, ΔΙΣΑΣΤΗΡ=ΔΙΣ+ΑΣΤΗΡ=DOUBLE STAR, an event, which causes as a result, "DISASTERS"
ΤΗΝ ΓΛΩΣΣΑΝ ΜΟΥ "ΕΔΩΣΑΝ" ΕΛΛΗΝΙΚΗΝ