Interplanetary Dust

Interplanetary dust is considered very important as it is thought to play a huge role in the formation and evolution of the solar system and may have actually formed water on our planet.

Cosmic dust is made up of tiny particles at the nanometer and micrometer levels. These particles appear at the end of a star's life and at the creation of a solar system.

Stars form from the combustion of a gas cloud made up of hydrogen and helium. They use the hydrogen to create heavier elements through nuclear fusion. These elements of carbon, oxygen, and other types are released at the end of a star's life where it collapses on its own gravity and creates a supernova, which is the biggest explosion in space. There are heavier elements which are formed from this supernova and create this interplanetary dust.

These interplanetary dust particles in our own galaxy are mostly made from comets which provide evidence for theories about the formation of planets.

Sources:
http://www.nasa.gov/audience/forstudents/5-8/features/nasa-knows/what-is-a-supernova.html
http://www.iflscience.com/space/what-interplanetary-dust-and-can-it-spread-ingredients-life