ELi ON EARTH: Time Change Will Help the Lazy of East Lansing See Zodiacal Light

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Monday, March 9, 2015, 12:00 am
Aron Sousa

Image, courtesy of NASA: City lights are at the horizon on the left, zodiacal light is the faint, white light that starts in the center and angles up and left, while the light of the Milky Way starts in the center and angles up and right. 

In the astronomical spring days, about an hour before dawn, the observant East Lansing resident has a shot at seeing zodiacal light in the east.

The recent time shift (Sunday morning) to an hour later means that more of us will be getting up before dawn for work and school. While ELi On Earth (EoE) might hope that the intellectual curious of East Lansing would awaken early just to see this astronomical event, we at EoE are an empirical lot and know better based on our own household survey. But it will be no extra effort to get out of bed this week to look east before dawn and look for the faint triangle of white glowing zodiacal light over the eastern horizon.

Zodiacal light is sunlight scattered by solar dust orbiting the sun. The dust is in the same plane as the earth and other solar bodies. It can be easy to mistake zodiacal light for the glow from a city’s lights. A city’s glow will be more yellow than zodiac light and will follow the geography of the city and not the zodiac.

The zodiac is the band of constellations that the planets (and sun) follow across our sky, and zodiacal light gets its name because the light is aligned with the zodiac. In the NASA picture shown above, the zodiacal light is the pale white light angling off to the left, compared to the Milky Way angling off to the right.

The zodiac itself is centered on the ecliptic, which is the specific path of the sun across the sky. (You can find more on EoE’s coverage on the ecliptic here.) The ecliptic moves up and down in the sky with the seasons, and you can see this because the sun’s path is higher in the sky in the summer and lower in the sky in the winter.

In the spring, the ecliptic is most perpendicular to the horizon in the morning, which makes it easiest to see the zodiacal light just before sunrise in the east. In the fall, the ecliptic is most perpendicular to the horizon in the evening, which makes is easiest to see the zodiacal light just after sunset in the west. Whether in the east in the spring or in the west in the fall, the zodiacal light has the same white glow from sunlight scattered by solar dust.

In other news,

  • For those of you seeking an excuse to celebrate an anniversary, William Hershel discovered Uranus on March 13, 1781. So, on the 13th, , you could drink a toast to Uranus and Hershel’s telescope.
  • For those more interested in pie, consider celebrating pi day (3.14) with pie. The value of pi (3.14159….) makes this year (3.14.15) the penultimate pi-day for this century. Next year (3.14.16) will be the real blowout of pi-o-philia, since the date is even closer to the value of pi (3.14159...). The most hardcore circlophiles will hold out for this century’s tau day (6.28.32).


Editor's note: The author makes pie on Pi day. Do you? If so, contact us, and we'll feature your pi pies in a story.



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