What is the age of the earth? How are scientists sure?

BEIJING, May 28 (Xinhua) — If you look at the age of the Earth on science websites or popular science books, you will usually find that the result is “estimated to be 4.54 billion years” and a margin of error of plus or minus 50 million years. You may also be surprised to find that accepted estimates date back to the 1950s and have remained virtually unchanged since then, although significant advances in scientific knowledge in other fields have improved since then. So, what’s going on here?

What is the age of the earth? How are scientists sure?

The work of calculating the age of the earth can be traced back to distant ancient times. Aristotle, the ancient Greek philosopher, believed that time had no starting point and end, and he believed that the earth was infinitely ancient, while the religious scholars of ancient India believed that the universe was constantly exploding, expanding and collapsing, and then looping back and forth, and they calculated that the earth had existed for 1.97 billion years. According to Brent Dalrymple (G. In the Middle Ages, many Christian theologians studied the Bible for clues about the age of the earth, and their estimates ranged from 5471 to 7519, according to Brent Dalrymple’s book, The Age of the Earth. From the 18th to the 19th centuries, many scientists also came up with a variety of estimates based on clues, from the Earth’s cooling speed and sediment accumulation to the chemical evolution of the ocean.

As recently as the early 20th century, scientists discovered that the age of rocks could be calculated by measuring radioactive decay, a method known as radiochdatetry. In 1907, American chemist and physicist Boltwood proposed the Uranium-Lead Measure, which considered lead to be the final product of the radioactive decay of uranium. In theory, the age of a rock can be calculated by knowing the ratio of lead to uranium in a rock. The crux of the problem, then, is to find rocks that form at the same time as the Earth.

By the early 1950s, the California Institute of Technology had a name d’Iteron. Patterson, a geochemist who was involved in the Manhattan project to develop the atomic bomb during World War II, is even more relishing his calculation of the age of the earth. Patterson measured the composition of lead isotopes from meteorites in Canyon Diablo, as well as several other meteorite fragments. These space rocks are thought to come from asteroids in the solar system that formed at the same time as Earth. In 1953, Patterson produced an estimate of the Age of the Earth of 4.1 billion to 4.6 billion years, followed by a more accurate estimate in 1956: 45.5 to 0.7 billion years. Since then, only minor corrections have been made to meteorites and moon rocks.

Although Patterson’s breakthrough made him famous in the scientific community, he didn’t think it was a big deal. In 1995, in an oral history interview shortly before his death, he recalled that “no one cared” about the issue. “Even today, people don’t care about the age of the earth. In fact, there’s less attention to this than it was 40 years ago when I measured it. “It’s worth noting that Patterson’s study of lead distribution on the Earth’s surface found that lead concentrations in nature increased dramatically since the 20th century, much faster than they have accumulated over the past few billion years, and that industrial pollution, especially the burning of fossil fuels, is the main source of these lead. Aware of the problem, Patterson devoted the rest of his life to environmental protection. (Any day)