Common Elementary Particles
Several estimates imply that practically all the matter, when measured by mass, in the visible universe (not including dark matter) is in the protons of hydrogen atoms, and that roughly 1080 protons exist in the visible universe (Eddington number), and roughly 1080 atoms exist in the visible universe. Each proton is, in turn, composed of 3 elementary particles: two up quarks and one down quark. Neutrons and other particles heavier than protons, as well as helium and other atoms with more than one proton, are so rare that their total mass in the visible universe is much less than the total mass of protons in hydrogen atoms. Lighter particles of matter, although equal (electrons) or vastly more (neutrinos) numerous than protons, are so much lighter than protons, that their total mass in the visible universe is again much less than the total mass of all protons.
Some estimates imply that practically all the matter, when measured by numbers of particles, in the visible universe (not including dark matter) is in the form of neutrinos, and that roughly 1086 elementary particles of matter exist in the visible universe, mostly neutrinos. Some estimates imply that roughly 1097 elementary particles exist in the visible universe (not including dark matter), mostly photons, gravitons, and other massless force carriers.
Read more about this topic: Elementary Particle
Famous quotes containing the words elementary particles, common, elementary and/or particles:
“Listen. We converse as we live—by repeating, by combining and recombining a few elements over and over again just as nature does when of elementary particles it builds a world.”
—William Gass (b. 1924)
“When we are high and airy hundreds say
That if we hold that flight they’ll leave the place,
While those same hundreds mock another day
Because we have made our art of common things ...”
—William Butler Yeats (1865–1939)
“Listen. We converse as we live—by repeating, by combining and recombining a few elements over and over again just as nature does when of elementary particles it builds a world.”
—William Gass (b. 1924)
“O my countrymen!—be nice;Mbe cautious of your language;—and never, O! never let it be forgotten upon what small particles your eloquence and your fame depend.”
—Laurence Sterne (1713–1768)