Look Up For Zodiacal Glow

Updated: Apr 10, 2021

Until 13 April, a phenomenon that can only be seen twice a year is on display in the Northern Hemisphere's night sky (just before dawn if you’re in the Southern Hemisphere).

If the sky is clear, look towards the western horizon around an hour after sunset and you could see ‘zodiacal light’. NASA says that what we’re seeing in that faint glow - it looks like a pyramid of light - is “sunlight reflected toward Earth by a cloud of tiny dust particles orbiting the Sun.”

The space agency says that there’s now solid evidence that Mars, the dustiest of planets, is the source of zodiacal light, but nobody yet has the answer as to how the dust managed to escape the grip of Martian gravity. The dust cloud was discovered, and mapped, by the Juno spacecraft on its way to Jupiter in 2011 - thus ending centuries of speculation.

“The zodiacal light appears as a huge, softly radiant pyramid of white light with its base near the horizon and its axis centred on the zodiac (or better, the ecliptic). In its brightest parts, it exceeds the luminance of the central Milky Way,” says Dr. Roy Bishop, Professor of Physics at Canada's Acadia University

If you're unlucky with cloud cover for the next 10 nights, the zodiacal glow will be back again for the equinox in late September.

If you want to know more about the dust cloud, this 90 second NASA video does the trick: