How old is the Earth and how did scientists determine that?
|How old is the earth? 2020.|
It doesn't take a genius to realize that the Earth is very old. But how old is it really, and how do scientists know about its age?
Creationists are still trying to convince that our planet is only 6000 years old, and that people rode dinosaurs, and the whole history is compressed into this narrow time frame. And they make these claims without any scientific evidence.
Modern scientists, on the contrary, have many scientifically based arguments proving that the Earth is not only older than 6000 years, but its age is much older than this figure in hundreds of thousands of times - it is about 4.5 billion years.
First, let us easily disprove the claim that the Earth is 6,000 years old.
In Spain, researchers have discovered the world's oldest human faeces, which were deposited by the Neanderthals 50 000 years ago. We know this from the chemical composition and the fact that the deposits were found in a layer of rock 50,000 years old. What do you think about that argument?
But the Earth is even older, and the proof is the oldest rocks, over 4 billion years old.The oldest rocks on Earth to date are the Acasta Gneiss in northwest Canada near the Great Slave Lake, which is 4.03 billion years old. And stone deposits over 3.5 billion years old are found on every continent. Greenland has a rocks (3.7 to 3.8 billion years old) and samples in Western Australia are between 3.4 to 3.6 billion years old.
|The oldest known fragment of the earth's crust is about 4,030,000,000 years.|
Australia's research teams have discovered the oldest mineral grains on Earth.These tiny zirconium silicate crystals are as old as 4.3 billion years, making them the oldest materials found on Earth today. Their original rocks have not yet been found.
The age of these minerals, known as Zircons, was determined by a process called radioisotope dating, which involves the use of a mass spectrometer.
This set of methods allows scientists to find out the dates when ancient rocks were laid down - and therefore provides information on geological processes as well as evolutionary processes that have affected organisms preserved as fossils in successive layers.
Simply put, scientists measure the amount of radioactive decay in Zircons, which usually contains lead, which used to be uranium. Uranium has a half-life of 704 million years.
That means that in 704 million years, one gram of uranium will be reduced to ½ gram of uranium. And in the next 704 million years it will decay, leaving ¼ grams, and in the next 704 million years it will decay, leaving ⅛ grams and so on. In this case, the number of elements on which it disintegrates (in this case Lead-207) will increase accordingly.
Why would scientists study meteorites to determine the age of the Earth?Even the oldest Zircons are not as old as the Earth itself. Everything in our world will eventually erode or fall back into its crust. To get a truly accurate date of origin for our planet, scientists must look beyond its borders.
That's why they started to find out the age of rocks and minerals found in meteorites and asteroids.
|Fragment of an iron meteorite (2.6 g). The total mass of the found fragments is more than 30 tons. Fell about 20-40 thousand years ago in a few kilometers from Diablo Canyon, Arizona, USA. How old is the earth, 2020.|
In 1953, Claire Patterson measured the ratio of lead isotopes in meteorite samples from Diablo Canyon, which crashed into our planet about 20-40 thousand years ago. The result was a more accurate estimate of the Earth's age to 4.550 billion years, the most accurate age of our planet today.
But science is not standing still. As the dating methods are improved and modern technologies are developed, the age of the Earth may become even more precise.