Dinosaurs lived hundreds of millions of years ago, which is why modern scientists studying that time can only hypothesize what our planet was like at that time. Some of them relate to time. It is easy to guess that even before the invention of pocket watches, the length of the day, year, hour could differ from the present. So in what “time frame” did the inhabitants of the Earth live in the era of dinosaurs?
When did dinosaurs live?
It’s worth immediately explaining that dinosaurs are by no means the first creatures on planet Earth. Before them lived therapsids, archosaurs and other creatures, which are distant ancestors of the most famous creatures of the past. However, not many of their remains have been preserved, and it is much harder to study them.
The first dinosaurs appeared about 243-233 million years ago and quickly populated the planet. Interestingly, their direct ancestors - archosaurs were predominantly bipedal creatures, dinosaurs were divided into dozens of species, among which were four-legged and flying representatives. Scientists still cannot explain exactly what this evolutionary difference is related to. Greater preference is given to the theory of climate change and other living conditions.
Reigning on the planet for approximately 170 million years, the dinosaurs became extinct. It happened about 66 million years ago, and scientists still cannot formulate an exact theory of why this happened.It is known that gradual extinction began millions of years before extinction.
Someone is sure the reason is in an asteroid that fell on the planet and made living conditions unsuitable. Others adhere to the theory of climate change, changes in ocean level and other weather features. To find out the exact answer is not yet possible.
Day on Earth in the first millions of years of life
For a person, several decades is a long time, but for the Earth it is an instant. The planet began to form 4.5 billion years ago, and during this period many events occurred on its surface. We can say that she literally “has seen a lot”.
The planet has been forming over many millions of years. Atmospheres in the usual form for us did not exist then, and asteroids crashed into the Earth, almost without resistance. Some burned in the atmosphere, while other pieces crashed into the surface and became part of it; volcanic eruptions erupted on the surface. So the Earth gradually increased its volume and mass.
The constant rotation around its own axis and around the Sun gradually honed its shape, turning it into a ball. At that time, the Earth was in space much closer to the Sun and had a different climate.
Since the Earth's rotation speed was higher than the current one, the time of day and year in length significantly differed from the current ones. Scientists suggest that in the first millions of years after the formation of the Earth, the day lasted about 5 hours, and the year went 1500 days (since day 5 hours) by that time.
Most likely, this would continue to this day, if not the appearance of the moon.Since then, the length of day has begun to change.
The change of day on Earth over time
Scientists believe that the Moon - the only satellite of the Earth, appeared as a result of the collision of the latter with another planet. Part of the planet broke away and froze at a certain distance from the Earth, becoming its satellite.
Many people know that the Earth and the Moon influence each other in accordance with the laws of universal gravitation, and significant changes in the distance between them can greatly affect the planet.
In the first millions of years, the Moon was 15 times closer to the Earth and had a great impact on the Earth. Lunar gravity slowed the rotation of the Earth, gradually slowing it down. Because of this, the time of day began to increase gradually, and the rotation around the Sun became slower.
Interesting fact: in the first tens of millions of years, the Moon passed around the Earth a full revolution in 5 hours.
Thus, from the moment the moon appeared, a continuous process of increasing the day and year began. Over 4.5 billion years, the day from 5 hours stretched to 24, and the year decreased from 1,500 days to 365. Scientists were able to establish that now every 100 years the time of day is increasing by 0.002 seconds. Such a change seems insignificant, but if we consider it on the scale of the Earth’s life, then in a billion years the day’s duration on it will increase by about 5.5 hours, which is already significant.
The length of the day and year during dinosaurs
Now you can answer the main question of the article. Since dinosaurs lived in the period 243-66 million years ago, you can independently calculate the length of the day and time of year on Earth.
When the dinosaurs first appeared, the day lasted about 22 hours 40 minutes, and the year lasted 386 days. But when their accelerated extinction began, the day lasted on Earth for 23 hours 20 minutes, and the year was 375 days.
Short answer
Due to the continuous exposure of the Moon to the Earth, the time of day is gradually increasing. Due to its attraction, the satellite slows down the rotation of the planet, increasing the time of day by 0.002 seconds every 100 years. During the appearance of the dinosaurs, the duration of the day and year was 22 hours 40 minutes and 386 days, respectively, and at the time of their extinction - 23 hours 20 minutes and 375 days.
