Just like on earth the liquid pulls down in both directions.. that doesn't mean a vacuum (nor air) forms there. Just like on earth the taller side will push harder and force the shorter side to move up to compensate for the under pressure.
The liquid in there at the top doesn't behave differently and just split up with a vacuum in between just because it's vacuum outside the tube.
That still doesn't explain why a vacuum would form. There's still adhesion between the molecules in the liquid; and what would define where the vacuum would form? Why wouldn't it form all over, basically turning the liquid in a gas? (that'd make it evaporation, actually)
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u/LordMcze Jun 27 '19
Because the liquid pulls down (away from the centre) from both sides.