The age of the Earth is the time that has passed since the emergence of an independent planet Earth. The answer to the question of how old the world is is four and a half billion years old. This data is based on studies of meteoritic samples that 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 emergence and life on planet Earth for Christian philosophers was the Bible. As a rule, they gave "our house" only a few thousand years of age.
In the first century AD, Philo of Alexandria said 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 Maye in the eighteenth century. His foundations were based on geodata and his own reasoning, which at that time few people couldto impress. However, he was pretty 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 mineral samples are over a billion years old. Small zircon crystals in western Australia are among the oldest at present, at least four and a half million years old.
Based on a comparison of the light and mass of stars and the Sun, it was concluded that the solar system cannot be much older than these crystals. The meteorite nodules, which are rich in aluminum and calcium, are the oldest known examples formed in the solar system.
Their age is four and a half million years. This data allows you to establish how old the world, 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 origin of our planet started shortly after meteorites and those same concretions were formed. The exact age of the Earth is difficult to determine. Since the exact time of the birth of the planet is unknown. And a variety of theories give from a few to a hundred million.
Besides this, quite difficultthe task is to determine the exact age of the oldest rocks that come to the surface of the planet, as they are composed of minerals that vary in age.
Best estimate
Since 1948, a method has been developed to measure the age of magma rocks. Which is based on two methods: uranium-lead and lead-lead. Development was done by George Tilton and Claire Patterson. They believed that meteorites were material left over from when the solar system formed. Thus, by determining the age of one meteorite, one can also measure the age of the Earth.
In 1953, Patterson obtained samples of the Cañon Diablo meteorite. He estimated the age of the Earth at 4.5 billion years. And then he clarified this figure to 4.55 billion, plus or minus seventy million. This estimate, even today, has not changed much, 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 says that all four. It continues to this day.
Certain similarities that can be found in all organisms may indicate the presence of common ancestors that gave birth to all living things in our world. At the beginning of the Archean period, archaea and cyanobacterial mats were the most dominant life form.
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 for the appearance of eukaryotes dates back to 1.8 billion years ago. However, they may have happened even earlier. Their diversification picked up 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 available to perform specific functions.
Approximately 1.2 billion years ago, the first algae on Earth began to emerge, and about 4.150 million years ago, the first of higher plants appeared. Invertebrates originated in the Ediacaran period, and vertebrates - during the Cambrian explosion, about five hundred million years ago.
During the Permian, synapsids (ancestors of modern mammals) dominated large vertebrates. However, extinction events during this period took with them almost all marine species and about seventy percent of terrestrial vertebrates, which included synapsids.
A Brief History of Dinosaurs
During the restoration of the planet after this disaster, archosaurs became predominant among vertebrates. In the final phase of the Triassic, they gave rise to the dinosaurs, which already dominated during the Jurassic as well as the Cretaceous.
In those days, the ancestors of our mammals were small animals that ate mainly insects. After the events of the Cretaceous-Paleogeneextinction that occurred sixty-five million years ago, there were no dinosaurs left. Of the archosaurs, only crocodiles survived, and probably birds that descended from dinosaurs.
After these events, mammals began to grow, there was more diversity, because all their competition simply died out. Perhaps such huge extinctions accelerated evolutionary processes due to the opportunity for new species to differ.
Fossil remains show that flowering plants began to emerge approximately one hundred and thirty million years ago, in the early Cretaceous, or even earlier. It is possible that they helped in the evolution of pollinating insect species.
