An exhaustive study, led by the SETI Institute’s Peter Jenniskens and planetary scientist David Nesvorny of Colorado’s Southwest Research Institute, has solved two long-standing mysteries. Interestingly, it was the study of one well-known phenomenon that serendipitously solved a second, lesser-known mystery.
The primary focus of the NASA-funded study was to determine the true origins of zodiacal light. Originally attributed to the scattering of sunlight by solar system dust – an explanation recently refined to specify asteroid dust – the zodiacal light extends as a glowing cone up from the sunset or sunrise horizon to the ecliptic. Although this ethereal light is so tenuous as to be rendered invisible by moonlight and light pollution, it is readily apparent in darker skies and even bright enough to be followed across the ecliptic in the very darkest conditions.
In their paper, Cometary Origin of the Zodiacal Cloud and Carbonaceous MicroMeteorites – Implications for Hot Debris Disks, Jenneskins and Nesvorny confirm the zodiacal cloud mass as originating primarily, not from asteroids, but from the past violent and repeated disruptions of Jupiter Family comets. Moreover, these disruptions likely resulted in twenty-trillion-tons of dust, with hundreds-of-thousands of tons impacting our planet every day!
