1.   But over time, gaseous components condense on the surface of dust grains in the interstellar medium.

2.   Dust grains north of the star might scatter radiation with a left-handed twist, while grains south of it would give the radiation the opposite twist.

3.   The direction of twist of the polarized ultraviolet will depend on where the dust grains lie with respect to the star.

4.   Edwin Bergin of the Harvard-Smithsonian center suggests that the water is there, but in the form of ice that is coating dust grains.

5.   The astronomers located the cloud by measuring the invisible electromagnetic radiation emitted by the dust grains.