Dust to dust


  • Anonymous


A ring of asteroidal dust encircles the Earth, and a cloud of dust permanently follows the Earth in its orbit around the Sun, according to new infrared satellite observations reported in the June 29 issue of Nature. The findings by astronomers at the University of Florida, Gainesville, may also help explain the asymmetry of the zodiacal cloud that envelops the inner solar system, observed by the Infrared Astronomical Satellite, among others. Gravitational resonance holds the interplanetary dust, which likely comes from the asteroidal belt, in Earth's orbit, yet the resonant trapping also means that the particles may be knocked out of orbit to spiral toward the Sun by light drag and solar wind drag forces on a time scale of 10,000 years.