Entering a New Age of Time
By: Submitted by Sahil Swe
Imagine waking up one day to discover that there are twenty-five (25) hours in a day instead of the usual twenty-four. It might sound like a concept taken from a science fiction novel, but it is a real possibility that scientists are increasingly considering.
Recent studies have revealed that the Earth’s rotation is gradually slowing down, which means our days are becoming slightly longer over time. While these changes are imperceptible now, they could have far-reaching implications for the future of human life, technology, and our understanding of time itself.
How Time Began- A Historical Perspective
The concept of a “day” has always been tied to Earth’s rotation. Measuring time has always been associated with the motion of celestial bodies. Ancient civilizations thousands of years ago sought to understand time by looking up at the skies.
The Egyptians split up the day into twenty-four hours according to the sun’s movement. The Greeks later came up with water clocks and other sophisticated means of following time. The 24-hour system we use today was formalized by the Egyptians over 4,000 years ago, who divided day and night into 12 equal parts each.
Babylonian Astronomy: Developed a sexagesimal (base-60) system, influencing how we measure time today (60 minutes, 60 seconds).
Greek Contributions: Hipparchus and Ptolemy refined astronomical observations and connected timekeeping with Earth’s motions.
Mechanical Clocks: By the 14th century, mechanical clocks began to define daily life in Europe, independent of sunlight.
Atomic Clocks: In 1967, the second was redefined using the vibrations of a cesium atom, marking a transition from celestial to atomic time.
Across the centuries, mankind developed these systems into mechanical clocks and eventually atomic clocks, which are now accurate enough to mark time down to a billionth of a second. Despite technological advances, civil time still follows Earth’s rotation—an increasingly complex task as the planet’s spin changes.
All of these measurements, though, are made on the basis of one basic assumption — that Earth’s rotation is constant. This is no longer strictly true. Earth’s rotation is slowing down due to natural processes. While this slowing process is extremely slow — a matter of about one point seven milliseconds every hundred years — over the course of a million years or so, this difference, which seems infinitesimal now, can work up to a very large difference in the way that we keep time.
.What Do We Mean by a Day? Sidereal, Solar, and the Subtle Shift
When we say “a day,” it might seem like a simple 24-hour concept. But in scientific terms, there are actually several ways to define a day on Earth — and they don’t all measure time the same way.
1.Sidereal Day — 23 hours, 56 minutes, 4 seconds
A sidereal day is the time it takes for Earth to rotate 360 degrees relative to the distant stars. This is the true rotational period of Earth. Astronomers rely on sidereal time to precisely track celestial objects.
- Solar Day (Mean Solar Day) — 24 hours (on average)
This is the time from one solar noon to the next — when the Sun is highest in the sky. Because Earth is also moving in its orbit around the Sun, it has to rotate a little more than 360° for the Sun to appear in the same position. That extra rotation makes a solar day slightly longer than a sidereal day — by about 4 minutes.
- Apparent Solar Day — Varies slightly each day
This is the actual time between two observed noons, measured using a sundial. Due to Earth’s elliptical orbit and tilted axis, this value fluctuates throughout the year. The “equation of time” helps correct for these variations.
So, when scientists say Earth’s rotation is slowing, they’re talking about changes to these very cycles — especially the solar day we live by. Over centuries, even slight shifts can change how long our days feel and how we define time itself.
Why the Earth is Slowing Down
The primary reason behind the slowing of Earth’s rotation is a phenomenon known as tidal friction. This occurs due to the gravitational interaction between the Earth and the Moon. As the Moon’s gravity pulls on the Earth, it causes the ocean tides to move.
These tidal movements create friction with the Earth’s surface, gradually slowing its rotation. At the same time, the Moon is moving away from the Earth at a rate of approximately three point eight centimeters per year.
In addition to tidal friction, other factors also contribute to the gradual change in Earth’s spin. These include the redistribution of mass caused by melting glaciers, changes in the atmosphere, seismic activity such as earthquakes, and the dynamic movement of the Earth’s molten core. While some of these effects are short-term and cyclical, the long-term trend is a slow but steady reduction in the speed of Earth’s rotation.
Evidence from the Past
Scientific evidence shows that the Earth’s rotation has not always been the same. Fossil records and geological data suggest that hundreds of millions of years ago, Earth had more days in a year because each day was shorter. For example, fossilized coral reefs from about four hundred million years ago indicate that there were over four hundred days in a year, meaning each day lasted only approximately twenty-two hours.
With the invention of atomic clocks in the twentieth century, scientists have been able to measure tiny differences in time with unprecedented accuracy. These clocks have shown that the length of a day is indeed changing, albeit very slowly. Since nineteen seventy-two, timekeepers have added twenty-seven leap seconds to the global time standard to keep atomic time in sync with Earth’s actual rotation.
Effects on Human Life
Although the current changes in Earth’s rotation are minor, they could have significant effects over time. One of the most immediate impacts could be on human health. The human body operates on a circadian rhythm that is closely aligned with the twenty-four hour cycle of day and night. If days become longer, even by a few minutes or hours, it could disrupt sleep patterns, affect mental health, and increase the risk of chronic diseases.
Another area that would be affected is technology. Many modern technologies, including global positioning systems, satellite communications, and internet networks, rely on extremely precise timekeeping. A change in Earth’s rotation would require constant recalibration of these systems, and even a small misalignment could lead to serious disruptions.
Societal and Cultural Implications
Beyond biology and technology, the slowing of Earth’s rotation would also influence our social structures. Time zones, work schedules, school hours, and international coordination are all based on the twenty-four hour day. A longer day would necessitate changes to these systems. For instance, countries might need to redefine what constitutes a workday or adjust their calendars to align with the new length of a day.
Religious practices and cultural traditions that are tied to specific times of day could also be affected. A shift in the structure of a day might require reinterpretation or realignment of long-standing customs and observances. These changes would not happen overnight, but they would become increasingly important as the effects of Earth’s slowing rotation become more pronounced.
Scientific and Technological Responses
In response to the slowing of the Earth’s rotation, scientists and technologists are already considering alternatives. One such proposal is the complete adoption of atomic time, which is not tied to the rotation of the Earth. This would mean allowing clocks and calendars to continue based on atomic measurements even as the length of a solar day changes.
Another approach would involve more frequent use of leap seconds or leap minutes to adjust timekeeping systems gradually. Some researchers also propose developing flexible systems that can adapt to changes in time measurement, allowing societies to transition smoothly as the natural length of a day evolves.
At length – Looking to the Future
While the idea of a twenty-five hour day may seem distant, it is a reminder that our planet is constantly changing. These changes may be slow, but they have the potential to reshape the fundamental ways we live, work, and interact with the world. As our understanding of time deepens, so too must our readiness to adapt to a future where time itself may no longer follow the patterns we have always known.
The slowing of Earth’s rotation is not a cause for alarm, but it is a call to prepare. From updating technology to rethinking societal norms, the journey into a new age of time has already begun. It challenges us to think not only about how we measure time but also about how we live it.
Earth’s gradual slowing rotation reminds us that nothing in the universe is truly constant. Over millions of years, even small changes accumulate, altering the very fabric of our daily lives. The possibility of longer days may not immediately impact us, but it is a clear signal that time, as we know it, is evolving. As science continues to monitor these shifts, we must remain curious, informed, and prepared to adapt to the changing rhythms of our world.
(The author is a Researcher at NIT Srinagar. He is a regular contributor to ‘Kashmir Vision’)
