RIA Novosti 
January 9, 2013
New observations made by Herschel space observatory show that asteroid Apophis, which is considered the most serious “space” threat to Earth, is bigger than first estimated, the European Space Agency said on its website on Wednesday.
Apophis, dubbed “the doomsday asteroid” in the popular media, swept by Earth on Wednesday at a little less than one-tenth of the distance from Earth to the Sun – about 9 million miles (14.5 million kilometers).
ESA’s Herschel space telescope observed the asteroid for about two hours on its approach to Earth and refined estimates of the asteroid’s diameter from 890± 200 feet to 1,070±50 feet (from 270 ± 60 meters to 325 ± 15 meters).
“The 20 percent increase in diameter, from 270 to 325 meters, translates into a 75 percent increase in our estimates of the asteroid’s volume or mass,” ESA quoted Thomas Müller of the Max Planck Institute for Extraterrestrial Physics, who is leading the analysis of the new data.
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