How old is the earth!
By measuring isotopes in rock samples, natural decay time geologists estimate the birthday of the Earth, 4.6 billion years ago, when the Earth was born from the nebula of the solar system, how long this time, we use analogy to help understand.
For example, suppose that the earth, the past history, is a Gregorian calendar year.
On January 1, the Earth began to form.
Earth first appeared on March 3.
Traces of single-celled bacteria (life on Earth has been continuous with single cells) until 11 November, when multicellular organisms began to appear.
Both Ediacaran Fauna, shortly after December 16, 18.08 minutes
It was the Cambrian explosion of life, an important milestone in life on Earth, when most of the modern animal phylum began to appear, and by December 10, 13:26, dinosaurs appeared
But two weeks later, it was destroyed by the asteroid,
On December 31, the mighty Roman Empire lasted less than four seconds
Three seconds before midnight, Columbus, set out for america (at this point he thought it was India).
If you were to write the history of the Earth on paper, each piece of paper would record a year, and your book would be 233 kilometers thick, more than half the height of the International Space Station
3.2 million years ago, the story of Lucy's ancient ape man is on the page of the 231 km of the book
Almost 152 meters from the last page, the signature certificate of the American Declaration of Independence, the last 1.3 centimeters
Or do we take the entire history of the earth? Compared to the length of a woman with her arms outstretched at 1.8 meters, she only needs to cut a nail, which is equivalent to erasing human history
Finally, analogous to the history of the earth and your life, such as from your birth, the beginning to the time you step into the high school campus, say your first word, the first time you sit up, the first time you walk, all occur during the single-celled life of the earth.
In fact, multicellular life on Earth appears when you are twelve years old and in the first or sixth grade of junior high school
Dinosaurs appeared three months later, and then immediately became extinct during the winter break, the first three days of junior high school, just after the summer when you were going to prepare high school supplies, the ancient apes were wandering around Africa, and then when you finished breakfast and were ready to go to school, the Neanderthals in Europe were facing extinction, and the most recent ice age was when you were about to end up in school, when you had sixteen minutes to go to class, and when you had a little while to go to class, Columbus was now sailing. A little while later, as you were entering the classroom, the Declaration of Independence was signed.
Compared with the history of human beings, the age of the earth is very old, unimaginably old, those fossil records, hidden in the amazing past, can even predict our future, but in this short period of time, human beings have mastered a lot of scientific and technological knowledge, and will be in the next decade or the next century, will be more progressive, although only the moment of the history of the earth.