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.)
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Famous quotes containing the words current state, origin, current and/or state:
“Reputation runs behind the current state of affairs.”
—Mason Cooley (b. 1927)
“Though I do not believe that a plant will spring up where no seed has been, I have great faith in a seed,—a, to me, equally mysterious origin for it.”
—Henry David Thoreau (1817–1862)
“But there, where I have garnered up my heart,
Where either I must live or bear no life;
The fountain from the which my current runs
Or else dries up: to be discarded thence,
Or keep it as a cistern for foul toads
To knot and gender in!”
—William Shakespeare (1564–1616)
“... the idea of a classless society is ... a disastrous mirage which cannot be maintained without tyranny of the few over the many. It is even more pernicious culturally than politically, not because the monolithic state forces the party line upon its intellectuals and artists, but because it has no social patterns to reflect.”
—Agnes E. Meyer (1887–1970)