China to launch Einstein probe to explore ever-changing universe

Conceptual image of the Einstein Probe satellite. Photo courtesy of the Microsatellite Innovation Institute of the Chinese Academy of Sciences.

Xinhua News Agency, Beijing, March 16 (Reporters Yu Fei and Yang Chunxue) China plans to launch a new X-ray astronomical satellite, the Einstein Probe, at the end of 2023, which is expected to capture the first ray of light from a supernova explosion, help search for and accurately locate the source of gravitational waves, and discover more distant and fainter celestial bodies and fleeting mysterious phenomena in the universe.

Yuan Weimin, chief scientist of the Einstein Probe satellite and researcher at the National Astronomical Observatory of the Chinese Academy of Sciences, introduced at the 35th National Space Exploration Academic Seminar held recently that the satellite project has entered the final development stage of the prototype.

Yuan Weimin said that there are many spectacular and magical transient sources and explosive sources in the universe. Most of them can radiate huge amounts of energy in a very short period of time, showing complex brightness changes in the X-ray band, appearing and disappearing from time to time, such as black holes that are devouring stars and the brilliant "fireworks" that bloom when stars die.

"Fast transient sources are produced in critical stages of the evolution of celestial bodies and the formation and evolution of compact objects. We are still unclear about some of their physical nature and processes. They are probes for cosmology and galaxy research, and also laboratories for exploring physical laws under extreme conditions." Yuan Weimin said that X-rays are an important band for transient source detection, but the transient sources discovered by scientists so far are only the tip of the iceberg in the universe. A new generation of detection equipment with extremely large field of view, high sensitivity, high resolution and rapid response capabilities is needed.

Yuan Weimin, chief scientist of the Einstein Probe satellite and researcher at the National Astronomical Observatory of the Chinese Academy of Sciences, introduced the relevant situation at the 35th National Space Exploration Academic Seminar (photo taken on March 1). Xinhua News Agency (Photo provided by the Chinese Society of Space Science)

Inspired by the unique focusing and imaging principles of lobster eyes, scientists have designed a special new X-ray telescope with both an ultra-large observation field of view and higher detection sensitivity.

"In other words, this telescope can see a very wide range while also seeing the darker and more distant universe. Thanks to the use of the Lobster Eye Telescope technology, the Einstein Probe Satellite can conduct large-field-of-view, high-sensitivity, and rapid time-domain survey monitoring of the soft X-ray band that is currently little known," said Yuan Weimin.

He introduced that many celestial bodies in the universe have soft X-ray radiation, and the sensitivity of the Einstein probe is relatively high, so the detection targets of this satellite are very broad. Its core scientific goal is to discover X-ray transients and drastically changing celestial bodies in the universe, monitor the activity of known celestial bodies; explore the properties of these celestial bodies and phenomena and related physical processes; discover and explore the flares of dormant black holes in the universe; map the distribution of black holes to further understand their origin, evolution and how they accrete matter; and search for X-ray signals accompanying gravitational wave events to enhance understanding of extremely compact celestial bodies and their merger processes.

The X-ray Imaging Laboratory of the National Astronomical Observatory of the Chinese Academy of Sciences has been developing lobster-eye X-ray imaging technology since 2010. After years of key technology research, it has finally achieved a breakthrough, fully mastered the technology, and has completely independent intellectual property rights. The team carried out testing and verification of the technology on the Space New Technology Experimental Satellite launched in July 2022, and obtained and publicly released the wide-field X-ray focused imaging sky map for the first time in the world.

Paul Bryan, a renowned expert in the field and professor at the University of Leicester in the UK, said that this technology will bring revolutionary impetus to cosmic X-ray monitoring and also shows the huge scientific potential of the Einstein probe.

According to reports, the Einstein Probe is another space science satellite developed by the Chinese Academy of Sciences' Space Science Pioneer Project Phase II after Taiji-1, Huairou-1 and Kuafu-1. The European Space Agency, the Max Planck Institute for Extraterrestrial Physics in Germany and the French Space Agency jointly participated in the satellite project.