Origin and Current State
Atoms form about 4% of the total energy density of the observable universe, with an average density of about 0.25 atoms/m3. Within a galaxy such as the Milky Way, atoms have a much higher concentration, with the density of matter in the interstellar medium (ISM) ranging from 105 to 109 atoms/m3. The Sun is believed to be inside the Local Bubble, a region of highly ionized gas, so the density in the solar neighborhood is only about 103 atoms/m3. Stars form from dense clouds in the ISM, and the evolutionary processes of stars result in the steady enrichment of the ISM with elements more massive than hydrogen and helium. Up to 95% of the Milky Way's atoms are concentrated inside stars and the total mass of atoms forms about 10% of the mass of the galaxy. (The remainder of the mass is an unknown dark matter.)
Read more about this topic: Atom
Famous quotes containing the words origin and, origin, current and/or state:
“We have got rid of the fetish of the divine right of kings, and that slavery is of divine origin and authority. But the divine right of property has taken its place. The tendency plainly is towards ... “a government of the rich, by the rich, and for the rich.””
—Rutherford Birchard Hayes (1822–1893)
“Art is good when it springs from necessity. This kind of origin is the guarantee of its value; there is no other.”
—Neal Cassady (1926–1968)
“The English language may hold a more disagreeable combination of words than “The doctor will see you now.” I am willing to concede something to the phrase “Have you anything to say before the current is turned on?””
—Robert Benchley (1889–1945)
“On our streets it is the sight of a totally unknown face or figure which arrests the attention, rather than, as in big cities, the strangeness of occasionally seeing someone you know.”
—For the State of Vermont, U.S. public relief program (1935-1943)