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Chapter 5: Our Ever-Expanding Universe > The True Age of the Universe - Pg. 232

We have already seen that different curvatures of space cause the geometry of a trian- gle to change (see Figure 5-5). On a flat surface, parallel lines remain parallel, meaning that the edges of a triangle are straight and the angles of the triangle add up to 180 degrees. On a closed (spherical) surface, parallel lines converge so that a triangle's lines bend outward and the angles of the triangle add up to something greater than 180 degrees. On an open (saddle-shaped) surface, parallel lines bend apart so that a triangle's lines bend inward and the angles of the triangle add up to less than 180 degrees. The lines of the triangle formed by our observations while looking at an area of tem- perature fluctuation will conform to the curvature of space and thus determine how the area we're observing appears to us. If the universe is flat (W = 1), the image will appear normal, and the area will measure 1 degree across. A closed universe (W > 1) would bend the light coming from the area outward, magnifying the image and making the area look 1.5 degrees wide. An open universe (W < 1) would bend the light inward, demagnifying the image and making the area look 0.5 degrees wide. The WMAP calculations showed that our universe is indeed flat. Because we now know that our W = 1, we can determine how much dark energy makes up the universe. Early calculations showed that W M = 0.30, meaning that that the universe is 30 percent matter. This includes the 5 percent that is normal, baryonic matter and the 25 percent made up of dark matter. As for the rest of the makeup of the universe, W L gives us how much dark energy makes up the universe. Since W = W M + W L and we know that W = 1 and W M = 0.30, simple math allowed astronomers to predict that W L = 0.70, meaning that 70 percent of the universe is dark energy. This was later proven by WMAP when it determined that W L = 0.72.