According to know-it-all scientists, days here on Earth have actually grown longer and longer. We look into the grating, unwelcome research.
Your senses don’t deceive you; the days here on Earth are indeed growing longer and longer. According to scientists, they have been so for tens of millions of years.
This information comes from a recent study into an ancient timekeeper—an extinct rudist clam that lived 70 million years ago and belonged to a group of mollusks that dominated the role that coral now fills in buildings reefs. This ancient clam in particular once occupied a shallow tropical seabed which today is dry land in the mountains of Oman.
This species grew swiftly in dense reefs, generating a growth ring for every day of the nine years that it lived. Researchers have analysed the clam’s shell to gain insight into what time and life was like in the Late Cretaceous period, a period that began 145 million years ago and ended 66 million years ago. A period that also marked the end for both dinosaurs and these mollusks.
Modern science had already gathered that days used to be shorter, but a new method gives us the most accurate understanding of the time differences to date.
The scientists used a laser to pierce microscopic holes into the rudist clam’s shell. From this, they could examine the shell for trace elements which garnered a plethora of information about the environment at that time. The ancient shell showed great seasonal variations, affording scientists the capability to count the years.
They found that at the end of the Cretaceous period, a year was 372 days long and that days only spanned about 23 and a half hours. It is important to note that although the number of days in a year have changed, the length of one year has stayed constant over time, as Earth’s orbit around the sun seldom alters.
The culprit responsible for the longer days? The moon. The moon’s gravity creates friction from ocean tides and slows the Earth’s rotation. As the rotation slows, the pull of the tides accelerates the moon, leading to the moon moving further away from the Earth each year. At this present time, the moon pulls away about an inch and a half per year.
Modern science had already gathered that days used to be shorter, but this new method gives us the most accurate understanding of the time differences to date.
“We have about four to five data points per day, and this is something that you almost never get in geological history,” study lead author Niels de Winter, an analytical geochemist at Vrije Universiteit Brussel, said in a statement. “We can basically look at a day 70 million years ago.”