The sun is constantly losing mass through the solar wind, a stream of charged particles constantly blowing off the Sun. We know the Sun's current rate of mass loss.

请问，老师这里用blowing 不用blew 是因为blow的这个用法吗(of air, wind, etc. : to move with speed or force)？，这里的a stream of charged particles和风是同一种“物质”，他们会自发的移动，而不是被吹。off表示离开的意思。