Dark Matter and Dark Energy Dark matter and dark energy are important. They can help us know how the universe began. These two are the mysteries of the universe; they make up about 90% of the universe. They are mysteries because we believe they exist but cannot see or detect them. People wonder if they manifest as the same thing. Astronomers know very little about their constitution, so they cannot assume that they are related. Dark energy is a mysterious force that drives the expansion of the universe. Astronomers say the universe is expanding and the expansion is accelerating, so the unknown antigravity force at work is called dark energy. Dark energy has important consequences on the evolution of the Universe and the structure within it. The astronomer is hunting for dark energy, but how can we hunt for something we don't know about? Astronomers label it dark energy because it is believed to be the force that causes the universe to expand, but the cause of this expression is not energy. I point this out because some theories have fooled astronomers. Astronomers are able to specify how much the universe is expanding by measuring this redshift from the supernova's spectrum. By studying many supernovae at different distances, astronomers can reconstruct the history of the expansion of the Universe. This expansion has given astronomers proof that there is dark energy out there causing the universe to expand. Dark matter is the next largest ingredient, interacting with the rest of the universe only through its gravity. Astronomers believe that the Universe is in a critical balance between being open and closed. They derive this fact from the observatio... middle of paper... concept used by astronomers and other scientists to understand the heavens. Considering the Earth as the core of the world, the celestial sphere is composed of the objects detectable from the Earth. When using an armillary sphere, people can estimate the position of something in the sky relative to a viewer on Earth. This model can also be used to show people how the celestial sphere works. The armillary sphere is today considered of scientific interest. These machines can be used for some simple astronomical calculations. Many examples are displayed in scientific museums that collect ancient instruments. Some people collect vintage spheres because they find them visually exciting. Armillary spheres are usually works of art as well as working examples; they can differ widely in size from desktop versions for devices that fill large rooms