S&T: Zodiacal Light's Mystery Solved
Posted: Thu Mar 11, 2010 4:53 pm
Zodiacal Light's Mystery Solved
Sky & Telescope - 2010 March 11
The zodiacal light is towering and unmistakable in this September
2009 image taken minutes after sunset from the European Southern
Observatory's La Silla Observatory in Chile. (ESO / Y. Beletsky)
By taking images when the Sun (dot at center) was blocked by the Moon's limb,
the Clementine spacecraft captured the true extent and shape of the zodiacal
light inside Earth's orbit. (Colors indicate intensity.) The combined light from all
this glowing dust would outshine Venus by dozens of times. (Joseph Hahn)
A computer-simulated zodiacal light created primarily from asteroid-
derived dust (solid line in upper panel) is a poor fit to the latitudinal
distribution observed (dashed line). Instead, the dust must be derived
almost entirely from short-period comets (solid line in lower panel).
Gray bars indicate interference from the Milky Way. (D. Nesvorný et al)
Sky & Telescope - 2010 March 11
http://lanl.arxiv.org/abs/0909.4322As my S&T colleague Tony Flanders describes in his observing blog, this is a particularly good time of year for northern skygazers to seek the night-sky glow known as the zodiacal light.
Eerie and elusive, it appears after evening twilight as a towering but feeble cone of light that, under ideal, ultradark circumstances, can be traced far along the ecliptic.
The zodiacal light is towering and unmistakable in this September
2009 image taken minutes after sunset from the European Southern
Observatory's La Silla Observatory in Chile. (ESO / Y. Beletsky)
By taking images when the Sun (dot at center) was blocked by the Moon's limb,
the Clementine spacecraft captured the true extent and shape of the zodiacal
light inside Earth's orbit. (Colors indicate intensity.) The combined light from all
this glowing dust would outshine Venus by dozens of times. (Joseph Hahn)
A computer-simulated zodiacal light created primarily from asteroid-
derived dust (solid line in upper panel) is a poor fit to the latitudinal
distribution observed (dashed line). Instead, the dust must be derived
almost entirely from short-period comets (solid line in lower panel).
Gray bars indicate interference from the Milky Way. (D. Nesvorný et al)