Glow Of The Heavens
Zodiacal Light mystery
Disrupting comets (white and red v's) rather than asteroids (green) contribute most of the dust that makes up the zodiacal cloud (purple haze and inset)
Zodiacal lightthe faint white glow that stretches across the darkest skies, tracing the same path the sun takeshas mystified scientists for centuries. Every day, Earth sweeps up about 140 tons of cosmic dust. The particles are mostly 100 micrometers to 200 micrometers in size and made of silicate minerals. Most burn up in the atmosphere, although some survive and end up in micrometeorite collections. To figure out how this dust behaves in the inner solar system, planetary dynamicist David Nesvorný of Southwest Research Institute in Boulder, Colorado, and five colleagues set up a computer model. The new modeling has "produced a detailed and convincing case that [90% of] interplanetary dust particles and the hundreds of particles that are now curated on Earth originate from Jupiter family comets," writes planetary scientist Stanley Dermott of the University of Florida, Gainesville, in an e-mail. Comets throw up the dust veil that creates the zodiacal light, and they supply most of the micrometeorites studied on Earth. Massive numbers of comets may even produce the bright debris disks seen around other stars. Now if only light-polluted skies didn't deny most people a view of comets' death glow.
For all latest news, follow The Daily Star's Google News channel.
Comments