Earth’s speed is faster now than half a century ago. Scientists fear they might have to take a second off the atomic clock if this continues. 

Through history, there have been variations in the rate at which the planet spins about its axis.

Earth actually rotated around 420 times per annum millions of years ago. But, it now rotates about 365 times.

The speed of rotation may vary, which can affect the global clock, or the atomic timekeeper. In these cases, leap seconds must be added to the total world’s running times. 

Peter Whibberley from the UK National Physical Laboratory has now warned that, should the rotation rate increase further, it may require a second negative.  

Earth is spinning faster than it was half a century ago, and if it continues speeding up scientists say they may have to remove a second from the atomic clock

Earth’s speed is faster now than half a century ago. Scientists fear they might have to take a second off the atomic clock if this continues.


Over the course of the world’s 4.6 billion-year history, the Earth has rotated around its own axis or turned about its orbit.

It would have rotated 420 times in one orbit of the Sun millions of years ago, but it is now 365.5 times.

It rotates once in about 24 hours with respect to the Sun, but once every 23 hours, 56 minutes and 4 seconds with respect to other distant stars.

It’s been slowing over millions of centuries, but scientists have observed a slight acceleration since 2016.

It is because of the Moon’s tidal effect on Earth’s orbit. It is possible to get A

Modern-day times are approximately 1.7 milliseconds longer than those of a century ago. To make leap seconds, tomic clocks must be used. 

Every day of the year contains 86.400 seconds. However, the Earth’s rotation doesn’t follow a uniform pattern. This means that each day can have a fraction or more of a second over the course of the year. 

The Earth’s core and its oceans, atmosphere and atmosphere all move in this way, along with the Moon’s pull.

Atomic clocks can be extremely precise. They measure time by measuring the motion of electrons in atoms that are cooled to absolute zero.

To keep the Earth’s orbit in time, leap seconds are added approximately every 18-months since 1972.

Negative leap seconds – the loss of an electron from the Atomic clock – have not ever been observed. Also, systems designed to do that work were never tested. 

This idea was brought up in last year’s rotation speedup. But, it has since slowed again with 2021 seeing an average of 0.39 milliseconds more than 2020.

Discover Magazine was told by Judah Levine, National Institute of Standards and Technology, that “as time progresses, there is an accelerating divergence between time of atomic clocks and time measured using astronomy.”

“To keep this divergence in check, it was decided that leap seconds would be added to the atomic clocks every so often.

International Earth Rotation and Reference Systems Service monitors how fast Earth spins. This is done by sending laser beams from satellites and measuring their movement. 

This is when scientists collaborate to reset their clocks to atomic time.   

The Earth’s rotation rate is complex. Levine stated that the rotation rate of Earth has to do with the exchange of energy between Earth, the atmosphere, and the effects from the ocean and the moon. 

“You can’t predict the future.”

Each day on Earth contains 86,400 seconds, but the rotation isn't uniform, which means over the course of a year, each day has a fraction of a second more or less

Every day of Earth has 86,400 seconds. However, the rotation of the Earth is not uniform. This means that each day can have a fraction or more of a second over the course of one year.

What is a LEAP SECOND?

A leap second is an adjustment of a single second to the Coordinated Universal Time (UTC).

It is intended to maintain the atomic clock and solar times in line.

There are difference between the incredibly precise International Atomic Time (TAI) measured by atomic clocks, and the imprecise observed solar time (UT1), linked to Earth’s rotation. 

UTC is a time standard that aligns with Greenwich Mean Time, (GMT), and it’s widely used in global timekeeping including astronomy.

UTC without the leap second added every few decades, UTC wouldn’t be in line with Earth’s orbit speed.

Although this would not be noticeable to the majority of people, it could change the Noon point over many centuries and impact the internet.

It isn’t popular, however, and can be disruptive to internet services. Google has been smooshing time for over a year in order to increase the microseconds per day.

Time is being considered by international standard bodies, which are responsible for tracking time. It would be a very slow drift even over 100 years.

The atomic clock hasn’t seen a leap second since 2016. And while the Earth was speeding up, it began slowing down again in 2021. 

Levine explained that it was impossible to predict the absence of leap second,

He added that it was assumed Earth would continue to slow down, ‘so this effect,’ he said ‘is very surprising.’ 

It is not yet clear how much longer scientists will need to monitor the slowing trend and determine what further actions they might take. 

Whibberley stated that there is a concern that Earth’s current rotation rate might increase further and that we may need what’s known as a “negative leap second”, Whibberley explained to Discover Magazine. 

“In other words: Instead of adding an additional second for Earth to catch up to it, we must take out one second from the Atomic Timescale to get it back in line with Earth. 

Scientists know what they can do, but they aren’t sure if their system would be practical or have any impact.

The steady flow of time is what the internet depends on. Atom clocks measure this. Different web companies use different methods to determine leap seconds.

Google’s system, for instance, spreads extra time over the entire year to each second.

Levine stated that the primary backbone to the internet’s existence is its continuous time.

The continuous flow of information becomes unstable if it is not constant. 

Levine suggests that adding or subtracting leap seconds may not prove to be worthwhile as the total would add up only to about one minute for every 100 years. 


Atomic clocks have a timekeeping mechanism that use the interaction of electromagnetic radiation with the excited states of certain atoms.

These devices measure time with the best accuracy and have consistent standards.

They serve as the main standards for international time distribution and control wave frequency to TV, GPS and other service.

It is based on atomic physics. This method measures the electromagnetic signal which electrons from atoms emit when they have changed energy levels.

Modern systems cool atoms with lasers. Their accuracy is determined by the temperature of the Atoms.

A ‘leap year’ is an addition to the atomic clocks. This effectively stops them for a second and keeps them aligned with Earth’s orbit speed.