SPACE — How long is an Earth day? Scientists now have the most appropriate answer.
So far we know that one day on Earth lasts 24 hours, or 86,400 seconds. However, this figure turned out to be incorrect.
The length of a day on Earth depends on how long it takes our planet to complete one rotation. This often changes only slightly.
The changes are often caused by dramatic events such as earthquakes and volcanic eruptions, as well as more subtle shifts caused by liquid metal in the Earth. The outer core of the earth moves around the solid core of the earth.
These millisecond-level disturbances are small and unpredictable. However, measuring it accurately is very beneficial. In the new calculations, a day on Earth is 24 hours plus or minus 6 milliseconds.
“Rotational fluctuations are not only important for astronomy, we also urgently need them to create accurate climate models and to better understand weather phenomena like El Niño,” said Ulrich Schreiber, professor at the Technical University of Munich (TUM) in Germany in a statement.
“And the more precise the data, the more accurate the predictions,” he said, as quoted from Space.com.
Schreiber and his colleagues have just measured very subtle changes in the length of the day with unprecedented precision. They use laser ring gyroscopes. It is a 4 meter wide square “race track” located in a pressurized chamber at the Wettzell Geodetic Observatory, a facility in Germany.
The device is located in bedrock at a depth of 6 m, so its laser beam is only affected by variations in the Earth’s rotation and not other environmental factors.
The gyroscope has two laser beams. One moves clockwise and the other counterclockwise.
If the Earth were perfectly balanced, both rays would travel the same distance. But the equipment experiences the same wobbles as the Earth, so one of the two laser beams travels a slightly smaller distance than the other.
By calculating these differences, Schreiber and his colleagues found that our planet’s rotation changed slightly over time, fluctuating by up to 6 milliseconds over a period lasting about a few weeks.
The scientists reported the results in a paper published in September 2023 in the journal Nature Photonics.
In the coming months, the researchers plan to further refine the laser gyroscope so that it can provide more precise measurements.
2023-11-16 14:38:00
#Long #Day #Earth #Scientists #Turns #Hours #Space #Space
