My thoughts on the matter is that :
1) morality is merely a human/biological construct. There's no morality in Saturn, Jupiter, asteroids or the Sun. There's no morality in water or in fire. Without intelligent life species like us, nothing would be or be called "right" or "wrong". The death of a star is not a bad or wrong thing, neither is the birth of a blackhole.
2) Morality is an evolutive advantage. We have morals because it helped us develop and prosper globally as a species, just like some animals exhibit simple "altruism". But in the end it is purely or reward system playing tricks on "us" (here by us I mean rational beings without ethics). Morality is therefore largely innate, unlike social taboos like incest.
3) Morality is not a social norm, but there exists things that are very much like ethics but purely societal, like aforementioned taboos. Morality is way less flexible than that.
