- 3642 - EARTH’S - shortest day? Our planet had been observed to be spinning more slowly and taking longer to complete a day. As a result, with every passing century, Earth has been taking a few milliseconds longer to complete a spin. This long-term trend has been reversing. The Earth seems to be speeding up and taking progressively less time to complete its spin meaning days are shortening.
--------------------- 3642 - EARTH’S - shortest day?
- Earth's shortest day since its rotational period began to be recorded with highly precise atomic clocks was on June 29, 2022. Earth's spin was completed in 1.59 milliseconds under 24 hours.
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- A day lasts 24 hours because the Earth completes a full spin on its axis roughly every 8,640,000 milliseconds. This speed can fluctuate by factions of a millisecond from day to day. This means that the length of a day can vary by a tiny amount.
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- In December 2020, during that year the Earth had experienced its 28 shortest days since scientists began measuring the length of a day with atomic clocks in the 1960s.
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- July 19, 2020, was a record-breaking short day that year with Earth completing a rotation in 1.47 milliseconds under 24 hours. The record remained unchallenged during 2021 before being broken by a minus 1.59 millisecond day on June 29, 2022. I knew I needed more sleep.
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- Just a month after the record for the fastest day was shattered, that second place day was once again dethroned further when Earth experienced a -1.50 millisecond day on July 26, 2022.
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- What could be causing Earth to suddenly begin speeding up its rotation and shortening its days? These ideas can involve processes in the planet's inner or outer layers, oceans, tides, or even its climate.
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- The shortening of days could be related to a small irregular movement in the Earth's geographical poles and its axis of rotation that shifts them by a minuscule amount across its surface called the 'Chandler wobble.'
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- The normal amplitude of the Chandler wobble is about three to four meters at Earth's surface, but from 2017 to 2020 it disappeared.
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- If the decrease in day length continues then it may necessitate the introduction of a negative leap second to keep 'civil time' measured by highly reliable atomic clocks in sync with solar time, the movement of the sun through the sky from sunset to sunrise.
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- Earth, the third planet from the sun, is the fifth-largest planet in the solar system; only the gas giants Jupiter, Saturn, Uranus and Neptune are bigger. Earth is the largest of the terrestrial planets of the inner solar system, bigger than Mercury, Venus and Mars.
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- The radius of Earth at the equator is 3,963 miles. However, Earth is not quite a sphere. The planet's rotation causes it to bulge at the equator. Earth's polar radius is 3,950 miles, a difference of 13 miles.
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- Using those measurements, the equatorial circumference of Earth is about 24,901 miles. From pole to pole the Earth is only 24,860 miles around. Our planet's shape, caused by the flattening at the poles, is called an “oblate spheroid“.
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- Those numbers make Earth just slightly bigger than Venus, whose equatorial radius is about 3,761 miles. Mars is much smaller than both Earth and Venus, with an equatorial radius of just 2,110 miles.
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- The other rocky planets are much smaller than the gas giants. More than 1,300 Earths could fit inside Jupiter.
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- Earth's density is 5.513 grams per cubic centimeter. Earth is the densest planet in the solar system because of its metallic core and rocky mantle. Jupiter, which is 318 more massive than Earth, is less dense because it is made primarily of gases, hydrogen.
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- Earth's mass is 6.6 sextillion tons. Its volume is about 260 billion cubic miles. The total surface area of Earth is about 197 million square miles. About 71% of our planet is covered by water and 29% by land.
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- For comparison, the total surface area of Venus is roughly 178 million square miles , and that of Mars is about 56 million square miles.
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- Mount Everest is the highest place on Earth above sea level, at 29,032 feet, but it is not the highest point on Earth. That is, the place most distant from the center of the Earth. That distinction belongs to Mount Chimaborazo in the Andes Mountains in Ecuador. Although Chimaborazo is about 10,000 feet shorter (relative to sea level) than Everest, this mountain is about 6,800 feet farther into space because of the equatorial bulge.
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- Everest and Chimborazo are nowhere near the tallest mountains in the solar system, however. The peak rising from Rheasilvia Crater on the asteroid Vesta is about 14 miles tall. Mars' huge Olympus Mons volcano is nearly as high, at 13.6 miles , and it covers an area the size of the state of Arizona.
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August 5, 2022 EARTH’S - shortest day? 3642
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