Isn’t time a fascinating concept? If you’ve ever had the feeling that the days are getting longer, then your instincts are clear. People in countries like Australia will soon switch to Daylight Saving Time. Just as Australia moves its clocks forward an hour for summer, the United States will turn its clocks back for fall.

The transition will not be available to everyone. Only 70 per cent of Australians are turning the clocks forward to take advantage of the extra sunlight. In America, states such as Arizona and Hawaii do not observe daylight saving time.

So why do we have longer days in the summer and shorter days in the winter?

Tilted Earth and Daylight Saving Time

The Earth revolves around the Sun in a nearly circular orbit. But there is a small problem. The axis of our beloved Earth is tilted 23.44 degrees relative to its orbit around the Sun.

This tilt remains the same as the Earth rotates around the Sun. Therefore, regardless of the Earth’s position, the sky bar always remains at the same angle as the tilt. This particular slope is the reason for our long summer days and those comfortable, short winter days.

The scenario gets interesting when you consider how this tilt affects each hemisphere differently. On one side of our orbit around the sun, the tip of our metaphorical stick points toward the sun. This begins with summer in the Northern Hemisphere and winter in the Southern Hemisphere. However, when the Earth gets tired of this position and changes sides, it manages to shine (literally!) when the bottom of the stick points to the sun – a bell in the north in winter and in the south in summer.

Winter and summer solstice

Remember those extremes we talked about when the Earth is on either side of the Sun? These different points are known as solstices. 21 June is the shortest day of the year in Australia, and 21 December is the longest day. Between these solstices is the equinox, when day and night coincide, dividing the hours equally.

This balance occurs when our celestial rod is perfectly “sideways” relative to the sun. In 2024, Australians will be able to observe this balance on March 20 and September 22.

Length of a day on Earth

Daylight saving time does much more than deprive us of an hour of sleep (and increase our coffee consumption). It changes our time to provide us with more daylight in the evenings; This works wonders for night owls, but isn’t the best news for morning owls. This tilt of the Earth was not always 23.44 degrees. Our smart planet changes its tilt from a minimum of 22.1 degrees to a maximum of 24.5 degrees approximately every 41,000 years.

Also, our day length was not always exactly 24 hours. The length of the day changes constantly by the minute, carefully monitored by a system of telescopes and satellites. Interestingly, due to the gravitational pull of the Moon, the length of the present day increases by approximately 2.3 milliseconds per century.

Effect of switching to summer time

Cyclical changes in daylight and seasons have profound effects on human activities; It affects the rhythm of society, agriculture and even mood. Historically, longer daylight hours helped farmers maximize yields by increasing the time needed to care for fields. Similarly, industries that rely on natural light benefit from reduced energy costs over these extended periods.

Psychologically, an abundance of sunlight during the summer months is associated with increased vitamin D levels and improved mood, often leading to increased productivity and well-being. Conversely, shorter days in winter may lead to seasonal affective disorder (SAD) in some people, suggesting the powerful effects of natural light on human health and behavior.

The future of daylight saving time

There is an ongoing debate about the effectiveness and appropriateness of daylight saving time (DST) in today’s world. Supporters argue that daylight saving saves energy by reducing the need for artificial lighting in the evenings and therefore reducing electricity consumption.

But critics question its practical benefit, citing disruptions in human circadian rhythms and limited energy savings in modern societies that work less during daylight hours. Around the world, positions on daylight saving time are divided, with some countries abandoning the practice altogether. As technology and society evolve, the future of daylight saving time may depend on balancing its traditional goals with the realities of modern life.