The earth was born hundreds of millions of years ago, and how many billion years ago was life on ear

Based on the determination of the decay rate of radioactive materials on Earth, it is known that our Earth has existed for 4.6 billion years, that is, our Earth was born 4.6 billion years ago.

In 1896, uranium, a natural radioactive element, was discovered in Berquerel, France. In 1905, it was discovered that the rock had radioactive characteristics. Later, through further research, it was found that the specific age of the rock could be determined based on the rate of metamorphosis of the radioactive elements in the rock.

For example, the uranium-lead method can be used to determine the actual age of rock formation. Because one gram of uranium (U235) will always fission into lead and helium in a year, the age of the rock can be calculated as long as we sample the rock according to certain requirements and determine the ratio of the radioactive elements uranium (U235) to lead (PB237) in the rock with special instruments. This method is called isotope age mapping.

Isotopic age is also called absolute age. In addition, the age of the rock can also be measured by using the rubidium-strontium method, the potassium-argon method, the C14 method, etc. In comparison, it is more desirable to use the uranium-lead method to measure very old rocks.

Through the above methods, the ancient rocks of the original crust are calculated, and the ancient rocks on the earth are generally not less than 3.6 billion 3.7 billion years old. Up to 4 billion years.

In addition, because the age of the earth at the time of formation is similar to the age of the solar system, "the stones of other mountains can be used to attack jade", scientists use some meteorites that fell on the earth and lunar rocks (soil) collected from the moon, after measurement, and the age of the oldest rock on the earth, the age of the earth can be deduced, about 4.6 billion years. For example, the age of the Jilin meteorite is 4.7 billion years old by rubidium-strontium method. The material that makes up the Jilin meteorite was separated from the Sun's primordial nebula 4.7 billion years ago, so it is a little older than the age of the Earth when it was formed.

At present, it is generally limited to 4.6 billion years, and the period since the beginning of the paleocravid in 4.6 billion years is the geological time of the earth, also known as the paleogeographic sphere period; The period 4.6 billion years ago is called the "astronomical period", also known as the "pre-geological period".

Earth is the third planet in the solar system from the inside to the outside, and it is also the terrestrial planet with the highest diameter, mass, and density in the solar system. It is also often referred to as the world. The English word earth comes from Old English and Germanic languages.

The Earth is 4,446 billion years old, and a natural satellite, the Moon, orbits the Earth in a 30-day cycle, while the Earth rotates in a cycle of nearly 24 hours and orbits the Sun in a one-year cycle. Disney has a documentary of the same name.

About 4 billion years old.

The history of life refers to the history of the development of life, which has existed on the earth for 3.8 billion years, and has been constantly changing since its birth, continuing and evolving in the midst of change.

This is a real, long, and unfinished historical process. The history of life is not only the history of biological evolution, but also the history of the evolution of the earth, the history of the entire natural world (living and non-living parts). Life on Earth is as old as the oldest rocks on Earth, that is, in the early Archean (3,53.8 billion years ago), life in cellular form appeared.

Throughout the entire history of life on earth, from the origin of life to human civilization, it can be roughly divided into three stages.

1. The chemical evolution stage of pre-life.

Fossil evidence and stable isotope analysis of the Archean in Australia and South Africa show that life on Earth is as old as the oldest rocks on Earth, i.e., in the early Archean period (3.538 billion years ago), when life in cellular form appeared. If the chemical evolution of prelife took place on the Earth's surface, then this could only have happened 3.8 billion years ago and 4 billion years ago.

Why: Geologists – The Earth's crust has been gradually forming since about 4 billion years ago.

2. Biological evolutionary stage.

The birth of the earliest cellular life on Earth, that is, the first appearance of morphologically characterized and individual life with biological membranes separated from the outside world and internal membranes, marked the completion of the chemical evolution of pre-life and the beginning of biological evolution. The biological evolution that began with the emergence of the earliest cellular life has gone through three geological epochs: Archean (3.8 billion years ago, 2.5 billion years ago, 2.5 billion years ago), Proterozoic (2.5 billion years ago, 600 million years ago), and Phanerozoic (600 million years ago to the present), which lasted for 3.8 billion years.

3. The parallel and mutually restrictive stages of cultural evolution and biological evolution.

In the last few thousand years of the last few thousand years of the Phanerozoic, human beings on the earth entered the stage of civilization, and since then, the evolution of the biosphere has been more and more influenced and controlled by human activities, and human culture and biological evolution have interacted and restricted each other, which is the characteristic of the last stage of life history.

The Earth was born 4.6 billion years ago. The universe was born 15 billion years ago, laying the material foundation for the creation of the earth. The Earth as a planet originated 4.6 billion years ago in the primordial code of the Sun Nebula.

Since then, the Earth system has evolved from simple to complex, and the evolution of its components is both interconnected and mutually influential. The movement of the earth system and the resulting changes in the Namo landform, life phenomena and life activities together constitute the history of the earth.

The material that formed the primitive Earth was mainly the primordial material of the nebula disk, the composition of which was mainly hydrogen and helium, which accounted for about 98% of the total mass. In addition, there is solid dust and material thrown out during the early shrinkage evolution phase of the sun. During the formation of the earth, light matter was constantly separated from volatile substances such as hydrogen and helium due to the differentiation of matter.

Chemical changes in the early days of the Earth's formation.

As for whether the primitive earth was hot or cold, scientists also have different theories. Proceeding from the ancient theory of the origin of the earth, most people once believed that the earth was originally a molten body, and that the earth still retains its heat after billions of years of geological evolution. The results of modern research are more inclined to the theory of the origin of the earth's low temperatures.

Whether the early state of the Earth was hot or cold is still debated. However, whether it is the theory of the origin of high temperature or the origin of low temperature, the earth has generally experienced a stage from heat to cold, because the inner hole of the earth contains a heat source, so this cooling process is extremely slow, and the earth is still in the process of continuing to cool.

4.6 billion years ago.

Two research teams from Germany and the United States studied the latest findings when Earth and Mars were born.

20 million years earlier than originally thought.

Scientists generally believe that the solar system was born 4.6 billion years ago with a huge supernova explosion.

Hair. The shock wave of the eruption causes the remnants of gas to condense into clumps to form the sun, planets, moons, asteroids, and comets. But the timing and speed of the birth of these celestial bodies is difficult to estimate.

Plan. In this study, computer simulations of the evolution of the solar system showed that the Earth's gold.

The genus core may have formed between 20 million and 30 million years after the supernova explosion.

Previous geological evidence suggests that the formation time was 50 million years after the eruption.

Scientists point out that 20 million years is just 20 million years relative to the billions of years of history of the solar system.

A brief period of time; But in the early years of the earth, the difference of 20 million years meant.

Many things will be different.

Two groups of researchers from the University of Münster in Germany and Harvard University in the United States have published a new article in English.

The journal Nature separately reported that they studied the data from Mars and the free space.

Samples of meteorite fragments were compared with Earth's rocks, which were analyzed in which hafnium-128 and.

The content ratio of tungsten 128 to the two elements. A similar conclusion is that Earth, along with the terrestrial planets Mars, Venus, and Mercury, all had less than 30 million cores after the eruption.

years, of which the formation of the Martian core may have taken only 130 million years. This result will make people:

We can better understand what happened in the early days of the Earth and may also help explain the Moon.

Origin. Hafnium-128 is a radioactive element with a half-life of 9 million years, and the decay product is tungsten.

128.Due to its ease of bonding with metals, all tungsten entered it in the early days of the earth's formation.

Therefore, the existing tungsten-128 in the mantle rocks must all be hafnium-128 decay.

Target. The ratio of these two elements can be used as a radioactive "clock" to determine the earth.

The age of the globe, according to the latest estimates of scientists, is that the Earth was formed about 4.57 billion years ago.

The Earth was formed 4.6 billion years ago.

The formation of the primordial earth, before the formation of the earth, there were many asteroids in the universe that revolved around the sun, and these planets collided with each other to form the primordial earth. As the collisions gradually decreased, the earth began to slowly cool from the outside in, creating a thin crust – the earth's crust.

About 1.6 billion years ago, the Earth had only 9 hours of day and night, which was much faster than it is now, with more than 800 days per year. By 600 million years ago, the day and night had extended to 20 hours and the year had shortened to 440 days, and the Earth was gradually slowing its rotation, probably due mainly to the tidal gravity of the Moon.