Days on earth will last 25 hours

 Scientists Confirm days on Earth will last 25 hours instead of 24 hours in future

If you have ever heard that Earth will “soon” switch to 25-hour days, the key word you should question is soon. Scientists reveal that Earth's rotation is slowing down, and a 25-hour day could be in our future. The length of a day on Earth may not be as fixed as we once believed. For centuries, we’ve lived by the 24-hour cycle, but recent research reveals that the planet’s rotation is gradually slowing down, which could lead to days lasting 25 hours in the distant future. According to the study, Earth could eventually experience days that last 25 hours. The research used laser-based instruments capable of measuring subtle changes in Earth’s rotation with incredible precision. Based on these measurements, scientists predict that in 200 million years, Earth’s day could extend by an entire hour. The potential transition to longer days raises fascinating questions about how life on Earth might adapt. From adjusting timekeeping systems to biological effects on circadian rhythms, the consequences of such a change could reshape how humans live and work.

Scientists do expect Earth’s rotation to keep slowing down, but the change is so gradual that it is invisible in everyday life. Still, the idea is real, and it comes down to a simple tug-of-war between Earth and the Moon. The same forces that move ocean tides also act like a tiny brake on the spinning planet, adding time to the day one sliver at a time. For millennia, humans have lived by the 24-hour day, marking time with the rise and set of the sun. Yet, the true length of a day is not a simple 24 hours. In fact, the sidereal day, the time it takes for Earth to complete one full rotation relative to the stars, lasts 23 hours, 56 minutes, and 4 seconds. The small discrepancy in time is adjusted by the solar day, which we commonly recognize as 24 hours. According to Ground News, this seemingly steady rhythm is changing. Earth’s rotation has never been perfectly constant, and factors like gravitational interactions, internal shifts within the planet, and atmospheric changes all play roles in altering the speed of Earth’s spin. Earth’s oceans bulge because of the Moon’s gravity, creating tides which rise and fall as the planet spins. But the tidal bulges do not line up perfectly with the Moon, because the oceans and seafloor create friction, and that friction steals a little rotational energy from Earth. A clear, official walkthrough of this process is described in NASA’s eclipse and Earth rotation explainer. In practical terms, Earth’s spin slows down, and the Moon slowly drifts farther away as the system trades energy. If that sounds abstract, picture pushing a spinning office chair with your foot lightly dragging on the floor. The chair keeps turning, but it gradually loses speed.

A combination of internal and external forces influences the speed at which Earth rotates. The most significant of these is the Moon’s gravitational pull, which generates tidal forces on Earth. This interaction causes a slight frictional force that gradually slows Earth’s spin. The redistribution of mass within the planet, including movements of the Earth’s core and the effects of melting ice, also contributes to these shifts in rotational speed. Also, the precession of Earth’s axis, slow changes in the tilt of the planet, impacts the rate at which Earth rotates, albeit in more subtle ways. Most of us learn that a day is 24 hours, because that is how we run school schedules, work shifts and the alarm clock. But if you measure Earth’s spin using distant stars instead of the Sun, you get a slightly shorter value called a sidereal day, explained in simple terms by NASA’s Space Place. The difference is not a mistake, it is just two ways of measuring motion. Earth is turning while also moving around the Sun, so the planet has to rotate a bit more for the Sun to appear in the same spot in the sky again. Even the 24-hour “solar day” is not perfectly constant. It wobbles by tiny amounts, and over very long stretches of time it trends longer.

Thousands of years ago, Earth was spinning much faster. When the Moon first formed around 4.5 billion years ago, a single Earth day lasted only about 10 hours. Over time, the Moon’s gravitational influence slowed Earth’s rotation, gradually lengthening the day. By the time Earth reached the early stages of its current configuration, the day had stretched to between 19 and 20 hours. This deceleration has continued over the last 600 million years, and the trend shows no signs of reversing. The current average day length of 24 hours is a result of this complex, on-going process. This is where headlines can get sloppy. There is no calendar date anyone can circle. The best-known estimates point to a timescale on the order of about 200 million years, assuming the Earth-Moon system keeps evolving in broadly the same way. One line of research behind this discussion comes from a University of Toronto team, highlighted in an official explainer from the University of Toronto Faculty of Arts and Science. Astrophysicist Norman Murray is one of the researchers connected to this work on how Earth’s day length has changed over deep time. So yes, the 25-hour day is “on the timeline.” But it is so far off that it will not affect humans, civilization or even the shape of our calendars in any practical sense.

Tides are the long, slow drumbeat, but they are not the only influence. Earth’s rotation can shift slightly when mass moves around the planet, like when ice melts or large amounts of water redistribute. The link between climate-driven mass changes and Earth’s spin is discussed in a NASA overview of rotation changes tied to ice and groundwater. These effects still operate on tiny scales, but they show the day length is shaped by more than one process. Even big engineering projects can have a measurable impact in theory, which is why some readers connect this to Earth’s rotation. It is a reminder that, at high precision, Earth is not a perfectly rigid spinning top. You cannot feel Earth losing a tiny fraction of a second over a lifetime. So how do researchers know it is happening? They compare extremely precise clocks with astronomical observations and long historical records, including old eclipse timings. Modern timekeeping also tracks small mismatches between clock time and Earth’s rotation. That is why organizations like the International Earth Rotation and Reference Systems Service publish official bulletins tied to Earth orientation and timing. 

On the clock side, the National Institute of Standards and Technology (NIST) explains how leap seconds have been used to keep global time close to Earth’s rotation. The US Naval Observatory posts public leap-second announcements which shows how closely timekeepers watch the planet’s spin. Even though the effects of Earth’s rotational slowdown may not be immediately perceptible to most people, this study provides a fascinating glimpse into the dynamic forces shaping our planet. Currently, the 24-hour day remains a familiar constant, but the future could unfold very differently, with humanity facing a world where days may no longer adhere to the same rigid 24-hour pattern we’ve always known till today.