(Yicai) Aug. 21 -- A team led by Chinese scientists has dated the formation of the Apollo Basin, a major impact basin on the far side of the moon, to 4.16 billion years ago by studying the lunar samples collected from the Chang’e-6 mission last year.

The team from the Chinese Academy of Sciences' Guangzhou Institute of Geochemistry, led by CAS academician Xu Yigang, accurately determined the age of three samples retrieved by the Chang’e-6 lunar probe and, by integrating information sources such as remote sensing images and geochemical data determined that the Apollo Basin formed 4.16 billion years ago, according to a study published on Nature Astronomy yesterday.

These findings push back the date at which the Late Heavy Bombardment began on the moon by at least 100 million years.

The LHB is a hypothesized astronomical event during which a large number of asteroids and comets collided with the moon and formed giant impact basins. Scientists have long debated whether the LHB impact flux declined gradually or saw a sudden intensity peak about 3.8 billion to four billion years ago.

The Apollo Basin is located in the South Pole-Aitken Basin and is the largest secondary-impact structure in the region. Scientists believe that it likely formed concurrently with the onset of the LHB, making the determination of its formation date key.

Therefore, the Chinese team found that the LHB impact flux followed a trend of gradual decay -- a fact which does not support the hypothesis of a sudden surge between 3.8 billion and four billion years ago.

A separate study that Chinese scientists carried out on the Chang'e-6 samples was published in March this year, confirming that the South Pole-Aitken Basin formed some 4.25 billion years ago and providing critical insights for the understanding of the early evolution of the moon and the solar system.

The Chang’e-6 probe was launched from China on May 3, last year, and returned to Earth 53 days later. It brought back over 1.9 kilograms of samples from the far side of the moon, the first time in mankind history.

The research on the Chang'e-6 samples will continue to drive humanity's developing understanding of the evolution of the Earth-moon system, according to Xu.

Editor: Futura Costaglione