How do you measure the dust in space?

This is a single particle of interplanetary dust, its image captured with the help of a scanning electron microscope by researchers at the University of Washington and Germany's Institut für Planetologie.

Now zoom out and think about all the dust particles like this that float around the inner solar system. That amount of interplanetary dust is a "1 zodi", a unit of measurement I never even thought to assume existed.

Thanks, Lauren Rugani!

Image used via CC