This link has been bookmarked by 1 people . It was first bookmarked on 06 Nov 2006, by Robert A Gagnon.
Scientists tend to believe that the elementary structures underlying the world we observe are ultimately simple and beautiful, even (or especially) the structures we have not yet discovered. Still, this basic elegance does not always manifest itself directly -- the universe we see is something of a mess.
This pie chart is a rather prosaic representation of a truly impressive accomplishment: an inventory of the relative amounts of the different substances comprising our universe. Yellow is ordinary matter -- atoms, molecules, dust, stars, planets, both visible and invisible -- or what cosmologists call "baryons" (since most of the mass of ordinary matter comes from the protons and neutrons inside atomic nuclei, and protons and neutrons are classified by particle physicists as baryons). Baryons make up about five percent of the known universe (actually closer to four percent, but let's not be picky). We know this from a variety of independent measurements, including the results of nucleosynthesis in the Big Bang, measurements of temperature fluctuations in the cosmic microwave background, and (less precisely) by direct detection. Everything we have ever seen is only one-twentieth of everything there actually is.
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