Carl Sagan told us long ago that we are stardust. Our planet earth and everything that lives on it was formed by the accumulation of dust grains in a collapsing dust cloud. Every atom in our bodies once resided in an interstellar dust grain. And before that, the dust cloud was formed by the condensation of heavy atoms in the debris expelled from exploding stars. Dust plays an essential part, not only in the history of life, but in the history of the universe as a whole. Although dust is a very small part of the mass of the universe, it controls the birth and death of stars and the heating and cooling of interstellar gas. Dust is prominent in the Hubble pictures, not only because dust clouds are beautiful, but because dust-clouds are big players in the cosmic drama. The Hubble pictures show the universe evolving all the way from the Big Bang to our pale blue planet. At every step of the journey, dust has guided our destiny.
(via azspot)
