The Earth is Accelerating! The Earth is in a "Fierce Spin" This Summer — How 1 Millisecond Shakes Technology and Humanity's Sense of Time

1. "The Short Summer Day" Has Arrived

"Today felt like it ended in an instant"—such a metaphor became slightly real in July 2025. According to IERS reports, Earth rotated 1.30 milliseconds shorter than 24 hours on July 9, with predictions of 1.38 milliseconds on July 22 and 1.51 milliseconds on August 5. This approaches the fastest record since the advent of atomic clocks. timeanddate.com

2. Triggers of Acceleration—Moon, Atmosphere, and Core

The factors influencing Earth's rotation are complex, but three key players are involved in this summer's acceleration.

1. Lunar Standstill
   The Moon's orbit is tilted about 5° relative to the equatorial plane. The "Major Lunar Standstill," when this tilt is at its maximum in an 18.6-year cycle, occurs in 2024–25, maximizing tidal torque at latitudes closer to the poles. This "pushes" Earth to spin faster, similar to a figure skater pulling in their arms. The Washington Post

2. Summer Jet Stream Brake
   During summer, when the Northern Hemisphere tilts toward the sun, the temperature gradient between the poles and the equator weakens, slowing the jet stream at about 10,000 meters altitude. As the atmosphere moves slowly, the conservation of angular momentum causes the lithosphere (the Earth itself) to accelerate slightly. This effect resonated with the lunar effect in July–August 2025. The Washington Post

3. Unknown Deep Dynamics
   Observations since the 1990s suggest a correlation between fluid motion within Earth's core and rotation speed. Dr. Duncan Agnew of the Scripps Institution of Oceanography notes that there is a "mysterious contribution from the core" in the recent acceleration. The Washington Post

3. The Weight of a Millisecond—Impact on Cutting-Edge Technology

1.3 milliseconds is only 1/80 of a human blink (about 100 ms). However, in financial markets where high-frequency trading (HFT) updates prices in nanoseconds, satellite positioning (GPS), large-scale power grids, and astronomical interferometers, **"time=coordinates"**, and errors can lead to coordinate shifts and system failures. Live Science

Especially for GPS, it calculates signal delays between satellites and receivers (1 ms at the speed of light ≈ about 300 km). If Earth rotates faster than planned, satellite calculations could shift positions by several tens of meters.

4. "Negative Leap Second" in Sight

When Earth rotates slowly, positive leap seconds are inserted to fill the surplus, but recently, the discussion has been about **"negative leap seconds."** In 2022, timekeeping organizations decided to abolish leap seconds by 2035, but if Earth's acceleration continues, negative corrections may be needed before then. Live Science

5. Humans Don't Notice—But Social Media Buzzes

The official TikTok video "Shortest Day of Your Life" by @dailymail surpassed 4.6 million views, with over 10,000 comments like "Earth should shorten Mondays too" and "If it's 1.5 ms shorter, overtime pay should be reduced too." TikTok

On X (formerly Twitter), #EarthSpinningFast trended, and a UNILAD post included a meme image saying, "Earth is spinning up? Please shorten office hours too." Many joked in DMs with friends, saying, "Oversleeping is Earth's fault." This light-heartedness symbolizes the spreading power of "science topics × social media."

6. The Long History of "Seconds Tug-of-War"

During the dinosaur era, a day on Earth was about 23 hours. It is believed that 4.6 billion years ago, the primordial Earth had days shorter than 19 hours. In the long term, the Moon is moving away, and Earth's rotation has slowed by about 2.3 ms per century. The recent acceleration may just be a wavy noise riding on that "long deceleration trend."

7. Future Scenarios—Will the Acceleration Continue?

• Short-term (~2026): As the Moon's orbit returns to the equator after fall 2025, it is likely to return to a slower rhythm by the end of the year.

• Mid-term (10–15 years): The melting of ice sheets may shift mass toward the equator, potentially slowing rotation slightly (Nature 2024 paper).

• Long-term (century scale): Expected to slow cumulatively due to lunar centrifugal motion and tidal friction.

※ However, there is a counterargument that "rebound uplift" of ice sheets will return mass toward the poles, making comprehensive predictions uncertain.

8. How to Cope with "Earth's Seconds"

What we can do is,

1. Enhance Science Communication—A good opportunity as social media shows interest even in millisecond scales.

2. System Agility—Automate timestamp corrections in cloud and distributed ledgers.

3. Education—Utilize in astronomy and earth science classes to let students experience "living Earth time."

9. Conclusion—Towards a World Where "A Day is Not 24 Hours"

Earth is a giant gyroscope, with a multi-layered system of the Moon, atmosphere, ocean, and core rhythmically tuning its rotation. The "millisecond shortening" of summer 2025 is a small window into this dynamism. Technology has become precise enough to not ignore these fluctuations, and social media discusses it with a touch of humor.

"Time is not absolute but an adjustable agreement"—Perhaps what is truly accelerating is the speed of our technology and information sharing.