IT’S THAT TIME of year again when we turn the clocks back by an hour as daylight saving time ends and standard time begins. The semiannual ritual always draws many opinions, but despite our efforts to modify day and night, there are astronomical factors at work which ultimately control how much daylight and darkness we receive each day.
Daylight has been slowly decreasing since the end of June when we reached the summer solstice. At our latitude, we experience nearly 15 hours of daylight around the summer solstice when the sun rises very early and sets very late. At the end of December during the winter solstice, we experience the least amount of daylight at 9 ½ hours. These changes in daylight and darkness occur because of Earth’s 23 ½ degree tilt on its axis along with its orbit around the sun throughout the year.
Daylight saving time and standard time do not change how much daylight and darkness we receive during a 24-hour period; they merely shift an hour of daylight toward the evening or morning. This year, standard time begins on Nov. 3, so after the time change, sunrise will occur an hour earlier than the day before which translates to more daylight in the morning but less in the evening with the hour earlier sunset. The change to standard time occurs when daylight is dwindling naturally, making the short days seem even shorter with earlier sunsets.
Over the last several years, there have been proposals by different states to abolish the time changes and remain with either daylight saving time or standard time all year, and there are advantages and disadvantages with each. If you prefer the latest possible sunset times especially during winter when daylight is shortest, then keeping daylight saving time all year is the best choice. Regardless of preference, sticking with a single time system throughout the year would finally end the pain and inconvenience of “springing forward” and “falling back” for everyone.
Saturn continues to be visible in the early evening sky just after sunset. Look for it near the thin crescent moon on the 29th. Pointing a telescope at Saturn will show its glorious rings which are nearly as wide open as they get.
Brilliant Venus reappears low in the southwestern evening sky just after sunset this month and will be close to the very thin crescent moon on the 28th. Jupiter will be to the lower right of the pair that evening.