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alokmohan
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Larry Rudnick looked deep into outer space and saw—nothing. The discovery thrilled him. <br />"I came home, sat at the dinner table, and told my wife, 'We found something pretty exciting today,'" says Rudnick, an astronomer at the University of Minnesota, Twin Cities. <br /><br />What he found was the biggest expanse of nothing ever discovered. Inside the void, there are hardly any galaxies, planets, or black holes—just mostly empty space spanning an area that's a billion light-years across. <br /><br /><br /><br /> <br />Stars and other objects fill most of the universe, but scientists were surprised recently to find a huge area of mostly empty space.<br /> <br />iStockphoto.com<br /> <br /><br /><br />To get a sense of how big that is, imagine standing outdoors on a night when the moon is full. Note how much space the moon takes up. The newly discovered void is 40 times as wide as the full moon from our view. <br /><br />The discovery of so much nothingness helps explain some mysteries about the universe, Rudnick says. At the same time, the newly discovered void raises new questions about how galaxies, stars, planets, and other structures formed. <br /><br />For a long time, astronomers thought that matter—which makes up everything in the universe—was distributed fairly evenly through space, with only small empty spaces and small spider-weblike structures. The new find calls that assumption into question. <br /><br /><br /><br /> <br />The newly discovered void is located in the constellation Eridanus, which represents a river in Greek mythology. Eridanus, illustrated here, lies near the constellations Orion, Canis Major, and Citus.<br /> <br />Image from Bayer's Uranometria (1661), courtesy of the Library of the US Naval Observatory; additions by Larry Rudnick.<br /> <br /><br /><br />"Something in the theory [about the formation of structure in the universe] might have to change," Rudnick says. In particular, the question of how matter has clumped together over time to form galaxies