David A. Wood Jr.
Too often, we are loose with our vocabulary, and we end up saying or writing one thing when we really mean something else. Then our intent changes meaning and confusion reigns. When you are an astronomer, this most commonly occurs when others mistakenly refer to you as an “astrologer.” Astronomy and astrology have a long, intertwined, and tense history, but there is a huge difference between them.
Astrology is a pseudoscience, having more in common with fortune telling than science. It claims to use the Sun, Moon, and planet positions against the background stars to predict human events on Earth. When an astrologer casts a horoscope for you, she claims that your day, week, month, or year are predestined by the relative positions of seven objects, most of which are tens of millions or even hundreds of millions kilometers away! Furthermore, generic horoscopes, based only upon the Sun’s position, attempt to describe the lives of 500 million diverse people whose only connection is that they were born in the same 30-day calendar period. Why, then, are some twins so different?
Astronomy, on the other hand, is a true science that relies on the scientific method to determine how the universe works. Astronomers are not going to cast a horoscope for you, but that doesn’t mean that astronomy doesn’t affect your daily life. In fact, just the opposite is true. Astronomical events are so fundamentally hard-wired into your DNA, that you unconsciously follow their patterns. Seasons are caused by the tilt of Earth’s axis. The Moon’s phase cycle affects everything from tides to fertility.
Weeks are divided into seven days, each originally to honor one of the seven moving celestial objects: Sunday is the Sun’s day; Monday (lunes) is the Moon’s day; Tuesday (martes) is Tews’s or Mars’s day; Wednesday (miercoles) is Woden’s or Mercury’s day; Thursday (jueves) is Thor’s or Jupiter’s day; Friday (viernes) is Freya’s or Venus’s day; and Saturday is Saturn’s day. Even the designations of a.m. (short for ante meridiem, means “before midday”) and p.m. (short for post meridiem, means “after midday”) are astronomical relics that remain in our lexicon.
There is one last dirty little secret that astrologers won’t tell you. Your horoscope sign is wrong by a month. Astrologers tell me that I am a Libra, and 5,000 years ago, the Sun was indeed in Libra in early October; however, thanks to a phenomenon called “precession,” the Sun drifted into Virgo in early October almost 2,000 years ago. So, should I read the Libra horoscope, or should I drift back a month to read the Virgo horoscope?
In the end it doesn’t matter. I get to choose my destiny. It is not predetermined by the random location of a few remote objects on the day I was born.
Dr. David A. Wood Jr. is the Director of Institutional Research, Planning, and Effectiveness. He is an astronomy instructor at SAC.