On average, the Earth actually rotates in 23 hours, 56 minutes, 4 seconds, and 90.5 milliseconds. This is called the sidereal day, which is the Earth’s ‘true’ rotation relative to distant celestial bodies in deep space, such as stars. However, the day most people experience is 24 hours, known as the solar day, which is the time between two consecutive sunrises. The extra four minutes come from the fact that the Earth has to rotate an additional degree, or 361 degrees, for the sun to appear in the same place again. Both types of days were slightly shorter on August 5, 2025, mainly due to the influence of atmospheric winds, the rotation of fluids in the oceans and magma, and even the moon’s gravity. Global positioning systems can pinpoint your location in space accurately, and this is not an issue, but if the Earth’s surface rotates slightly faster or slower than expected on that day, an uncorrected GPS system won’t recognize it, and your location won’t match your map. According to ‘Science’ magazine, the winds in the Earth’s atmosphere are the major factor affecting the length of the day. When they collide with the Earth’s surface, especially against mountain ranges, they slow down the Earth’s rotation. Earth’s prevailing winds are faster during the northern hemisphere’s winter but slower from June to August, so the summer months always have the shortest days of the year (although we tend to call them the ‘longest’ days in the northern hemisphere due to their long daylight hours). These daily and seasonal changes are just short-term flashes that add to broader slowdowns. Over decades, the melting polar ice caps have slowed the Earth’s rotation. Despite the moon’s beauty, it may pose a significant obstacle. Over billions of years, Earth’s oceans rise due to the moon’s gravity, but as the Earth rotates, these slightly elevated oceans move ahead of the moon in its orbit. The Earth’s rotational energy is not lost; it transfers to the moon, which gains orbital speed that allows it to better escape Earth’s gravity, which is why it moves away from us at a rate of 3.8 cm per year. Earth’s rotation has slowed annually from 1973 to 2020, accumulating hundreds of milliseconds of delay each year, which has been accounted for by adding 27 leap seconds. The days of July 5, July 22, and August 5 have been identified as the fastest days of this year in advance, because in addition to Earth’s internal movements and seasonal atmospheric wind fluctuations, the moon’s position in its orbit also slows Earth’s rotation. This is because when the moon is directly over the equator, its tidal pull moves from east to west, but on these dates, it is at its northernmost and southernmost points, weakening this effect.
