NASA scientists say a new study proves there are seven times as many big and potentially dangerous comets flying through deep space than previously thought. The study analyzed data from the Wide-field Infrared Survey Explorer (WISE) spacecraft that tracks "long-period" comets (LPCs) that take at least 200 years to orbit around the sun. WISE data showed far more LPCs that potentially pose a serious impact risk to Earth. "Previously the sense was that for every 100 asteroid impacts (of all sizes) we get 1 comet impact," Dr. Joseph A. Nuth, a senior asteroid scientist at NASA's Goddard Space Flight Center, told The Daily Caller News Foundation. "Now that we know there are more LPCs for every 100 asteroid impacts we might get 5 comet impacts." Astronomers previously gave broad estimates of the number of LPCs in the solar system, but researchers didn't have a good way to detect them since they were obscured by clouds of gas and dust. Gravitational forces can move LPCs back into the inner