Courtesy of EarthSky
A Clear Voice for Science
www.EarthSky.org
Today’s chart shows which zodiacal constellations are up soon after darkness falls on an evening in the middle of June. You are facing due south for this chart, looking southeast to west, more or less following the path the sun takes during the day.
One of you wrote, “What does Zodiac mean?”
The word “zodiac” just means “pathway of animals.” It is an important pathway across our sky because the sun moves across it during the day, and the moon and planets move across it at night.
In other words, speaking astronomically now (not astrologically), we live in a solar system that consists of planets orbiting a sun. The planets orbit our sun in a nearly flat plane. If you project that plane against our sky, you get a narrow pathway upon which the sun, moon and planets all travel. You all know this pathway. It is the path of the sun during day, as it travels from east to west.
The astronomical word for the plane of Earth’s orbit around the sun, which more or less defines the plane of the solar system, is “ecliptic.” In addition, we often speak of the ecliptic in the night sky. The zodiacal constellations are those upon which the ecliptic, or plane of the solar system, is projected in our sky.
Related:
Antares: Heart of the Scorpion
Zubenelgenubi: Alpha star of Libra the Scales
Written by Deborah Byrd
Astronomy Picture of the Day from NASA/JPL
U.S. Naval Observator Astronomical Information center
The York County Astronomical Society
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