The age of the Earth is called the time that has passed since the advent of the independent planet Earth. The answer to the question of how old the world is is four and a half billion years old. These data are based on studies of meteorite samples, which were formed even before the planets began to form.
Earth exploration
In ancient times, concepts such as the age of the entire Universe and the age of the Earth had strong differences. The basis for assessing the period from the moment of its origin and life on planet Earth for Christian philosophers was the Bible. As a rule, they gave "our house" only a few thousand years old.
In the first century of our era, Philo of Alexandria spoke out that it makes no sense to try to measure the time from the creation of the Universe by those units that were created after this very creation.
The first scientific assessment of how old the world is was given by Benoit de Maya in the eighteenth century. Its foundations were based on geodata and his own reasoning, which at that time could hardly impress anyone. However, he was quite close to the truth, estimating the age of our world at two and a half billion years.
Other scientists of that time were not so close to the correct data. However, the question of how old the world was was closed only at the beginning of the twentieth century, when the scientific discovery of the method of radioisotope dating was made.
Radioisotope dating
After this method was sufficiently developed, it turned out that most of the mineral samples are over a billion years old. Small zircon crystals in western Australia are among the oldest at the moment, they are at least four and a half million years old.
Based on a comparison of the light and masses of stars and the Sun, they concluded that the solar system cannot be much older than these crystals. Meteorite nodules, which are rich in aluminum and calcium, are the oldest known samples formed in the solar system.
Their age is four and a half million years. These data allow us to establish how old the world is, that is, the solar system, as well as the upper limit of the age of our planet.
One of the hypotheses about the origin of life is the assertion that the birth of our planet began shortly after meteorites and the same nodules formed. The exact age of the Earth is difficult to determine. Since the exact time of the origin of the planet is unknown. And the most different theories give from several to one hundred million.
In addition, a rather difficult task is to determine the exact age of the oldest rocks that go to the surface of the planet, since they consist of minerals of different ages.
The most accurate estimate
Since 1948, a method has been developed to measure the age of a magma rock. Which is based on two methods: uranium-lead and lead-lead. The development was conducted by George Tilton and Claire Patterson. They believed that meteorites are material left over from the time the Solar System formed. Thus, determining the age of one meteorite, we can measure the age of the Earth.
In 1953, Patterson took out samples of the Canyon Diablo meteorite. He estimated the age of the Earth at 4.5 billion years. And after he clarified this figure to 4.55 billion, plus or minus seventy million. This estimate, even today, has not been much changed, since in our time the age of the Earth is estimated at 4.54 billion years.
Evolution on earth
The development of living organisms on our planet began from the moment when the first living creature arose. It happened about three and a half billion years ago. Some data say that all four. It continues to this day.
Certain similarities that can be found in all organisms may indicate the presence of universal ancestors, who gave birth to all living things in our world. At the beginning of the Archean period, the most dominant life form was Archaea and cyanobacterial mats.
The photosynthesis of oxygen, which appeared about two and a half billion years ago, led to atmospheric oxygenation, which occurred around the same time period. The earliest evidence of eukaryotes dates back 1.8 billion years ago. Moreover, they may have occurred even earlier. Their diversification gained speed when they began to use oxygen in their metabolism.
Multicellular and other
Multicellular organisms began to appear about 1.7 billion years ago. They had differentiated cells in order to perform special functions.
About 1.2 billion years ago, the first algae on Earth began to emerge, and about 4.150 million years ago, the first of the highest plants appeared. Invertebrates, however, originated in the Ediacar period, and vertebrates - during the Cambrian explosion, about five hundred million years ago.
In the Permian period, synapsids (ancestors of modern mammals) prevailed in large vertebrates. However, nearly all marine species and about seventy percent of terrestrial vertebrates, including synapsids, took with them the events of extinction during this period.
A brief history of dinosaurs
During the recovery of the planet after this disaster, archosaurs became predominant in vertebrates. In the final phase of the Triassic, they gave rise to the appearance of dinosaurs, which already dominated during the Jurassic period, as well as the Cretaceous.
In those days, the ancestors of our mammals were small animals that fed mainly on insects. After the events of the Cretaceous-Paleogene extinction, which occurred sixty-five million years ago, not a single dinosaur is left. Of the archosaurs, only crocodiles and probably birds that descended from dinosaurs survived.
After these events, mammals began to grow, more variety appeared, because all their competition simply died out. Perhaps such enormous extinctions have accelerated evolutionary processes due to the emergence of new species opportunities for difference.
Fossil remains show that flowering plants began to appear about one hundred and thirty million years ago, in the early Cretaceous, or even earlier. It is possible that they helped in the evolutionary process of pollinating insect species.