Believe it or not, 600 million years ago, when some of the first plants and animals were roaming the earth, a day was only 21 hours long. How did we get to our present 24-hour day? The earth typically slows down its rotation by 1.8 milliseconds every 100 years. That may not seem like much. But over hundreds of millions of years, those milliseconds really add up! However, in 2020, scientists started to realize that the earth is actually spinning faster, not slower. This resulted in our shortest day ever recorded while tracking the length of days with the super-accurate atomic clock. July 29, 2022, was 1.59 milliseconds shorter than the typical atomic clock standard 24-hour day. The 28 shortest days on record (since we started tracking that 50 years ago) were all in 2020. What does this mean for us?
How do we even know how Fast the Earth is Spinning?
How can we calculate the earth’s rotations to the millisecond? The answer is atomic clocks. These clocks measure the frequency of an atom’s vibrations to track time incredibly precisely. The first atomic clock was built in the UK in 1955. In 1968, the definition of a second became the length of time of 9,192,631,770 cycles of radiation during the transition between two energy states of caesium-133. This is why atomic clocks are sometimes also called caesium clocks. Modern atomic clocks are accurate to within 10 quadrillionths of a second. The first ones were only accurate to 100 billionths of a second.
Coordinated Universal Time (UTC) is the time that helps to keep everyone on the same timeline across the whole world. It is based on International Atomic Time (TAI). However, UTC is 37 seconds behind TAI due to leap seconds and the fact that UTC started about 10 seconds behind TAI to begin with. TAI is an average time between 450 atomic clocks in more than 80 laboratories across the globe. Using these hyper-accurate clocks to track the exact amount of time that it takes the earth to do a full rotation helps us track the exact length of a day.
What Factors Affect how Fast the Earth Spins?
There are several things that can affect the spinning speed of the earth including:
- The tidal pull of the moon and/or sun
- Interactions between different layers of our earth’s core
- The way mass is distributed on the surface of the planet
- Extreme seismic activity
- Extreme weather
- The condition of the Earth’s magnetic field
- Glaciers growing or melting
Many experts believe that the earth is spinning faster due to the glaciers melting as a result of climate change, as well as increased stores of water in reservoirs in the northern hemisphere. Most of these experts also believe this speed-up is just temporary and at some point, the earth will return to its typical slowdown.
What does it mean if the Earth Spins Faster?
Given the natural disasters and stress of the past few years, it’s not surprising that many people on social media were frightened when they learned this news. It does sound unexpected. To most people, the rotation of the earth seems very steady and stable. However, it fluctuates by a tiny, imperceptible amount daily.
According to NASA scientists, although the shortest day ever recorded was on June 29, 2022, that day doesn’t even come close to the shortest day in the history of our planet. Most experts believe that the increase in speed of our planet’s spin is within normal fluctuations and is nothing to worry about. However, some are concerned about the potential cause.
As mentioned, many experts believe that the faster spinning could be caused by changing conditions due to climate change. In this way, humans might be indirectly changing important details about the future of our planet, even down to how fast it spins!
How Do We Deal With a Faster Spinning Earth?
Many of our modern technologies rely on hyper-accurate timing from atomic clocks for coordination including:
- GPS satellites
- Computer systems
- Communication networks
These technologies are the fabric of our functioning society today. If the atomic clocks become less accurate due to unexpectedly short days, some of these technologies could start to have issues or experience outages. However, there is a solution to this.
In the past, leap seconds were included in atomic timekeeping to account for the slowing of the earth’s spin. If we know the earth is moving faster, rather than slower, it may be possible to remove a leap second instead of adding one. That may be the best solution to keep us all on track if the earth continues this trend of faster spinning.
Some technology experts argue that the act of adding in a leap second itself could cause technology outages because it has not been tested on a large scale yet. However, scientists believe it is the best way to keep us all on track for correct timing over the long haul.
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The photo featured at the top of this post is © iStock.com/Thaweesak Saengngoen
FAQs (Frequently Asked Questions)
When was the earth's shortest day ever recorded?
July 29, 2022, was the earth’s shortest day ever recorded. However, it was not the shortest day ever in the history of the heart. That day was 1.59 milliseconds shorter than the typical atomic clock standard 24-hour day.
How short was the shortest day ever recorded on earth?
June 29, 2022 was 1.59 milliseconds shorter than the typically atomic clock standard date.
Is the earth spinning faster or slower?
In 2020, scientists discovered that the earth is spinning faster than it used to.
How long was a day 600 million years ago?
600 million years ago, a day on earth was only 21 hours long
How do atomic clocks work?
Atomic clocks measure the frequency of an atom’s vibrations to track time incredibly precisely.
When was the first atomic clock built?
The first atomic clock was built in the UK in 1955.
What is the definition of one second?
In 1968, a second was defined as the length of time of 9,192,631,770 cycles of radiation during the transition between two energy states of caesium-133.
How accurate are today's atomic clocks?
Modern atomic clocks are accurate to within 10 quadrillionths of a second.
What factors make the earth spin faster or slower?
The tidal pull of the moon and/or sun, interactions between different layers of our earth’s core, distribution of mass on the surface of the planet, extreme seismic activity, extreme weather, the condition of the Earth’s magnetic field, glaciers growing or melting can all make the earth spin faster or slower.
Is it bad that our planet is spinning faster?
Most experts believe that the increase in speed of our planet’s spin is nothing to worry about and is within a normal range.
What technologies rely on atomic clocks for accuracy?
Technology that relies on atomic clocks for accuracy includes GPS satellites, smartphones, computer systems, and communication networks.
What is a possible solution to keep timing accurate if the earth is spinning faster?
If we know the earth is moving faster it may be possible for the official timekeeping authorities to remove a leap second when necessary.
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- Wikipedia, Available here: https://en.wikipedia.org/wiki/Atomic_clock
- CBS News, Available here: https://www.cbsnews.com/news/earth-spinning-faster-and-recording-its-shortest-day-ever-is-no-reason-to-panic-scientists-say/
- Verify This (1970) https://www.verifythis.com/article/news/verify/science-verify/earth-spinning-faster-june-29-2022-shortest-day-in-modern-history-space-fact-check/536-29cc466b-ff7b-4ff8-9e8a-bbc31bd50651 https://space-geodesy.nasa.gov/news/news.html
- New Scientist, Available here: https://www.newscientist.com/question/fast-earth-spin/