The matter between the stars in a galaxy—called the interstellar medium—consists not only of gas, but also of a great deal of dust. At some point in time, stars and planets originated in such an environment, because the dust particles can clump together and merge into celestial bodies. Important chemical processes also take place on these particles, from which complex organic—possibly even prebiotic—molecules emerge.
Click here for original story, Astrophysicists prove that dust particles in space are mixed with ice
Source: Phys.org