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Dark Forces Dominate Universe The earth.moon.sun and all visible stars in the sky make up less than one percent of the universe.Almost all the rest is dark matter and dark energy，unknown forces that ____ astronomers. Observations in recent years have changed the basic____of how the universe evolved and have indicated how little is known about the major forces and substances that____ our world Astronomers now know that luminousmatterstars，planets and hot gas---- Accounts____ only about 0,4 percent of the universe.Non-luminous components，such as black holes and intergalacticgas， up 3.6 percent The rest is either dark matter , about 23 percent，or dark energy，about 73 percent. Dark matter.Sometimes____cold dark matter，has been known for some time.Only recently have researchers come to understand the key role it____formation of stars，planets and even people. We____ our very existence to dark matter, said physicist Paul Steinhardt and a co-author of a review on dark matter which____not long ago in the journal Science. Dark matter dominated the structure____in the early universe，Steinhardt said.For the first few billion years dark matter contained most of the mass of the universe You can think of ordinary matter____ a frothof an ocean of dark matter.The dark matter dumpsand the ordinary matter falls into it.That____ to the formation of the stars and galaxies. Without dark matter , there would be virtually no structures in the universe | 
