Today’s Wonder of the Day was inspired by Dylan. Dylan Wonders, “What makes daytime and nighttime?” Thanks for WONDERing with us, Dylan!
Are you a busy kid? You've got school all day, followed by homework. Throw in some extracurricular activities, like soccer or piano practice, and you find yourself trying to jam eating healthy, exercising, relaxing, watching television, hanging out with friends, playing, and getting enough sleep into a narrow window of free time each day.
Have you ever wished there were more hours in the day? Each and every day we have 24 hours to make the most of, but sometimes it seems like 24 hours just isn't enough to do all the things we want to do.
If you've ever wanted more time in the day, you're in luck. Scientists have learned that days on Earth are getting longer each year, and we have the Moon to thank for this phenomenon.
Before you get too excited, though, you won't really notice any difference in the length of days in your lifetime. The changes are very small, and scientists believe it takes hundreds of millions of years for them to add up to a noticeable difference.
As the Moon travels around Earth, it affects Earth's rotation. Scientists have determined that the Moon slowly gets farther away from Earth at the rate of about 1.5 inches per year. This movement causes Earth to rotate more slowly around its axis, similar to the way a figure skater begins to slow down as she stretches her arms out.
Researchers who have studied the interaction between Earth and the Moon believe that approximately 1.4 billion years ago, a day on Earth was just 18 hours long. At current rates of movement, they believe days on Earth are getting longer by about 0.000018 seconds each year.
How did scientists make these calculations? They used a new statistical method called astrochronology, which combines geological observation of very old rocks with astronomical theory to reconstruct the history of Earth and its interactions with the solar system.
Sound complicated? It is! Specifically, scientists were able to study ancient rock formations to track changes in Earth's orbital variation, known as Milankovitch cycles. These cycles are the result of orbital forcing, which are climate changes caused by changes in Earth's tilt, wobble, and orbit around the Sun.
Scientists also concluded that the rate at which the Moon is moving away from Earth has changed over time. Since the Moon is about 4.5 billion years old, they concluded that, at the present rate of the Moon's movement, it would've been too close to Earth to avoid being ripped apart long ago. As a result, they believe the Moon's movement away from Earth was much slower billions of years ago.