THE SKY THIS FEBRUARY: FEBRUARY IS QUIET TIME FOR THE SKIES

February represents a lull in astronomical activity as we prepare for the Messier Marathon in March (more on this next month). This lull gives us time to talk about one of the most important things about February, the calendar. The development of the calendar is a good illustration of how the scientific method works. It took thousands of years of observations followed by modifications to develop a calendar where the seasons always occur on fixed dates.

In ancient times there was little distinction between science and religion. We knew everything had a reason and purpose, we just could not figure out what it was. Ancient astronomers looked for perfection and magic numbers which resulted in the appearance of our current calendar.

They noticed there were seven objects which moved about in the night sky, the Sun, Moon, and five planets Mercury, Venus, Mars, Jupiter, and Saturn. In honor of these moving objects, a week was developed that had seven days. Seven was thus considered a magic number and was given special meaning. Even today we name the days of the week after these objects Sunday for the Sun, Saturday for Saturn, Monday for the Moon, etc.

The next astronomical event which caught their attentions was the phases of the Moon. Careful observations revealed there to be about 12 lunar cycles in a year. Thus the year was divided into 12 months. The number 12 was then considered magic and given special meaning (a dozen). Now we begin to have problems. Other timing events were supposed to be made up of even multiples of these magic numbers. While they could not fit an equal number of weeks in a month, they tried to force the issue for the number of months in a year and so established a year to be 360 days.

As you know the year has 365.242198 days. So, when using the old calendar, the seasons would creep up 5 days per year. After six years the calendar was off by a whole month! It was then decided to bend to science a little and have a year 365 days long. But, 365 was not evenly divisible by 12 months so every other month has 30 days and the rest have 31 except that we were short a few days so they gave February only 28 days.

This worked very well until the astronomers got better at predicting when spring would come and they realized they were missing 1/4 day per year. To make up for that they invented the leap day so that every fourth year February has 29 days.

As if this was not enough to make the perfectionist swallow their pride, adding a full day every fourth year was too much so every century the leap day was dropped except when the year was divisible by four. Thus February 2000 gets to keep its leap day.

With these rules our calendar is stable for a thousand years.

This month you can see four of the five naked eye planets crowding toward the Sun at sunset. Mercury puts on its best show on the 14th and is followed by Mars, Saturn, and Jupiter in the west. Venus is still bright in the morning but slips a little closer to the Sun each day.

Orion the hunter looms high in the south at sunset chasing the mighty bull Taurus. Both the red stars, Betelgeuse in Orion and Aldebaran in Taurus, are large cool stars that would engulf the Earth if they were our star.

Spring weather is very unpredictable so enjoy the clear nights when they come, even if they are cold, and rest up for the Messier Marathon next month.

Dr. Michael L. Cobb is the Chairperson of the Physics Department at Southeast Missouri State University and can be reached at 651-2172.