Comet Hyakutake gives off strong X-rays

17 Jun 2002

CNN-- Comet Hyakutake, which swept closest to Earth last week, emitted strong X-rays as it passed, according to U.S. and German scientists.Any level of X-rays would have grabbed the interest of scientists. However, Hyakutake burned a hundred times brighter in the X-ray spectrum than even the highest theoretical predictions of scientists who thought comets might give off such rays. Scientists also found pronounced increases and decreases in radiation coming from Hyakutake, with changes occurring over a period of hours.

Scientists do not know what caused the X-rays or why they wavered. One theory about why the comet is giving off X-rays is that X-rays from the sun were absorbed by a cloud of gaseous water molecules surrounding the nucleus of the comet, and then were re-emitted by the molecules in a process called fluorescence.

Another theory proposes that the X-rays are produced from the violent collision of the comet and the supersonic "wind" of plasma and particles streaming away from the Sun.