A year of 'out of this world' science achievements

The Einstein Probe (above) and the first X-ray all-sky map it obtained. （CCTV）

In February last year, the Large High Altitude Air Shower Observatory, perched atop a mountain in Sichuan province, discovered a giant ultra-high-energy gamma-ray bubble structure in the Cygnus star-forming region. This was the first super cosmic ray acceleration source to have ever been authenticated.

Cosmic rays are charged particles from outer space, mainly composed of protons. The origin of cosmic rays is one of the most important frontier issues in modern astrophysics.

Measuring gamma rays has become a very effective means of studying the origin of cosmic rays, said Cao Zhen, a scientist from the Institute of High Energy Physics at the Chinese Academy of Sciences.

Operating since July 2021, the observatory in Sichuan is the most sensitive ultra-high-energy gammaray detection device in the world.

It is located at an altitude of 4,410 meters on Haizi Mountain in Daocheng county, and made up of a 1-square-kilometer ground array of more than 5,000 electromagnetic particle detectors and more than 1,000 muon detectors and 18 wide-angle Cherenkov telescopes among other equipment.

The CAS is banking on the observatory being able to detect more sources of cosmic rays with energies ranging from tens of trillions of electron volts to even higher, offering the potential of solving the mystery of the origin of cosmic rays in the Milky Way galaxy.

In April, China released the world's first high-precision lunar geological atlas.

Since the implementation of the Apollo program by the United States in the 1960s, lunar geological research has used lunar geological maps developed during that era. With further research, these lunar geological maps were no longer able to meet the future scientific research and lunar exploration needs, according to the Institute of Geochemistry at the CAS.

Since 2012, a research team from the institute has used China's Chang'e lunar exploration mission scientific data as the basis to compile a series of 1:250,000 lunar digital geological-structural maps through the study and compilation of elements such as lunar rock structure, geological structure and age.

"This is a comprehensive integrated achievement in the field of lunar science, which not only provides basic data and scientific references for the formulation and implementation of scientific goals in lunar exploration projects, but also fills the gap in China's research on lunar and extraterrestrial planetary geological map compilation. It contributes to the study of lunar origin and evolution, as well as the evolution of the solar system," the institute said.

In May, a new achievement in the field of quantum science was published in the journal Science, with Chinese scientists realizing the fractional quantum anomalous Hall state of photons by designing 16 "photon boxes" on a 2 millimeter by 2 mm chip, and confining one and only one photon in each box.

This achievement can help researchers better understand and manipulate quantum systems, providing a crucial new foundation for quantum computing, said Lu Chaoyang, a member of the research team and a professor at the University of Science and Technology of China.

Lu said that this technology, known as quantum simulation, is a key component of the "second quantum revolution" and is expected to be applied to quantum computing in the near future.

The anomalous Hall effect refers to the observation of related effects without the need for an external magnetic field. Since the discovery of the fractional quantum Hall effect, scientists worldwide have been continuously trying various methods to observe and simulate this phenomenon.

"Previously, in electronic systems, the Hall state could only be observed under specific conditions; but with this artificially created photon system, control can be achieved, leading to higher flexibility and controllability," Lu said.

In October, the Einstein Probe, a space science satellite led by China's National Space Science Center at the CAS, released its first batch of scientific research results.

It discovered a special transient celestial body in April, which is highly likely to belong to a previously unknown category of transient celestial bodies.

The Einstein Probe satellite operates at an altitude of 590 kilometers above the Earth's surface, equipped with a wide-field X-ray telescope and a follow-up X-ray telescope. These are primarily used to monitor and follow up transient and eruptive celestial bodies in the universe, which are often related to theoretical predictions under Einstein's theory of relativity such as black holes and gravitational waves.

Since its launch on Jan 9 last year, the satellite has detected 60 confirmed transient celestial bodies, including stars, white dwarfs, neutron stars, various types of black holes, gamma-ray bursts, supernovae and more than 480 stellar flares.

The Einstein Probe Science Center, together with members of the satellite's science team, has sent out over 100 astronomical alerts to the international astronomical community, guiding follow-up observations.