A day would have lasted 65 hours if the sun wasn’t there – new research

The Earth’s rotation is gradually slowing thanks to interactions with the Moon. In fact, two billion years ago, there was a pause in these changes that lasted about a billion years. A new study not only explains it, but also calculates file size day If only this gap had not occurred.

Physicists have understood for centuries that the Moon is moving away from the Earth, and this shift in rotational momentum requires the Earth’s rotation to slow down, making the day longer. Recently, according to IFL ScienceGeologists have found evidence that allows us to measure the length of the day at multiple points in time, revealing the impact of this slowdown.

Instead of a steady process, the pace changed, including a long pause. A month ago, a publication gave estimates for the period when this happened and an explanation of why, and an estimate The Earth once had a 19-hour day.

What the new study shows about the length of the day

Another group of scholars came to similar conclusions about the causes, although the dating of the objects is slightly different. In their new study published in Science advancesHowever, go further and calculate how long the day would take if the aforementioned slowdown were unrelenting.

The explanation given by both groups is that the sun is speeding up the Earth’s rotation rather than slowing it down. For most of Earth’s history, this force was much smaller than that of the Moon, so the net effect was that the rotation slowed as much as it was under the influence of the Moon. However, during a period that geologists have called the “dull billion,” the power of the Sun was nearly as strong as to equal that of the Moon.

In detail, the moon creates tidal waves in the oceans and, to a lesser extent, in the atmosphere. Tides create friction on the ocean floor. The moon also attracts its causes, and because the moon lags behind the Earth’s rotation, both phenomena create resistance, slowing the Earth’s rotation.

“Sunlight also produces atmospheric tides with the same type of waves,” Norman Murray, professor of theoretical astrophysics at the University of Toronto and lead author of the new research, said in a statement. […] The sun’s gravity pulls on these atmospheric waves, creating torque on the Earth, but instead of slowing the Earth’s rotation like the Moon does, it speeds it up. ”

A billion years ago, the atmosphere was much warmer and composed of various gases. There was also a natural resonance in the atmospheric system corresponding to half the length of the day. All this increased the power of the sun, while the shorter-and-then-long day interfered with the coordination of tides on the moon.

“It’s like pushing a kid on a seesaw,” Norman Murray said, adding, “If the push and the swing aren’t in sync, it won’t go up much but if they are in sync and you push like the swing stops at one end of its path, the push will add to the momentum of the swing and it will go farther and higher.” ”

A subtle multiplier payoff works for the system’s natural resonance, too, as when Earth’s atmosphere had a 10-hour resonance and a day was 20 hours long. The study authors estimated that without the sun’s influence, the day would have stretched from 10 hours long when the Earth was formed to 65 hours today. In fact, if the days were 65 hours long, it would be warmer and the nights cooler.

As impressive as evolution is, it’s doubtful that many species could handle such wild temperature fluctuations. Life may not have ended on Earth, but it probably wouldn’t have ended in abundance.

“As we increase the Earth’s temperature with global warming, we also make the resonance frequency move higher – we move our atmosphere away from the resonance,” Norman Murray noted, explaining: “As a result, there is less torque from the sun and thus, the length of the day will get longer. , sooner than in the other case.