TPO - A new study suggests that the oldest evidence of Earth's ancient atmosphere may be hidden in rocks on the Moon. That is the result of the latest analysis of Moon rocks brought back to Earth by Apollo astronauts 50 years ago.
 |
Apollo 16 mission commander John Young uses a geologic hammer to sample a partially buried rock at the western rim of Plum Crater. Lunar sample 61016, examined in the study and better known as “Big Muley,” is located to the right of the rover. (Image: NASA, Apollo Lunar Surface Journal) |
At the time, scientists discovered traces of magnetism locked in rocks — a sign that the moon once had a magnetic field, much like Earth’s. This was puzzling, because magnetic fields are controlled by the core of a planet or moon, and the moon’s core is very small, said study co-author John Tarduno, a professor of earth and environmental sciences at the University of Rochester. But the new research suggests the moon has had no magnetic field for at least 4.36 billion years.
This new study, published in the journal Communications Earth & Environment, finds that the Moon may have only been protected by its magnetic field for the first 140 million years of its existence. This is exciting because it means that the Moon may hold a record of Earth’s earliest existence that was long erased from our own planet. Without its protective magnetic field, the Moon may have picked up ions from Earth’s atmosphere 4.36 billion years ago.
The Mystery of the Earth and Evolution
“One of the mysteries of the Earth and the evolution of the Earth is really what was the first component of the Earth's atmosphere?” Tarduno said. “We have no way of actually getting measurements of that on Earth.”
Very few rocks older than 3.5 billion years remain on Earth, and those that do have been heavily altered by Earth's constant tectonic plate movements. The Moon, by contrast, is geologically quiet, and there are layers of lunar soil—called regolith—that may have remained undisturbed for billions of years.
“If we can find a place on the Moon that records this really ancient regolith material, we might have a way to infer the early atmosphere of Earth from direct measurements,” Tarduno said.
In 2021, Tarduno and his team discovered that the Moon had no magnetic field 3.9 billion years ago. While the rocks as a whole show some general magnetization, this may be due to meteorite impacts. Individual crystals within the rocks, a better record of the geomagnetic field, do not have a specific magnetic orientation.
In the new study, Tarduno looked at older lunar samples and pushed back the possible date of magnetism on the moon by 400 million years. This is exciting, Tarduno said, because that time frame represents Earth’s earliest era, the Hadean. No Hadean rocks remain on Earth, and the planet’s early atmosphere remains a mystery.
According to Live Science
Source: https://tienphong.vn/bang-chung-lau-doi-nhat-ve-bau-khi-quyen-cua-trai-dat-co-the-an-trong-da-tren-mat-trang-post1671364.tpo
Comment (0)