One is non-breaking space and the other is a regular space. A non-breaking space means that the line should not be wrapped at that point, just like it wouldn’t be wrapped in the middle of a word.
Furthermore as Svend points out in his comment, non-breaking spaces are not collapsed.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…