https://www.cas.cn/yw/202507/t20250714_5076200.shtml

The CAS Institute of High Energy Physics has established the Ali Primordial Gravitational Wave Detection Experiment Phase I in the Ali region of Tibet, at an altitude of 5,250 meters. It was jointly developed by 16 domestic and international research institutions, including the CAS National Astronomical Observatories and Stanford University, took eight years to build and achieved its first clear images of 150 GHz radiation from the Moon and Jupiter.

If the universe is compared to humanity, primordial gravitational waves are the “first cry” of the universe in its infancy. This mysterious signal originates from quantum fluctuations in spacetime during the period of cosmic inflation and is the most primitive “ripples in spacetime” left over from the very early universe. If primordial gravitational waves could be detected, this would be a glimpse the ‘initial appearance’ of the universe.

Primordial gravitational waves are extremely weak, and their signals are hidden in the polarization of the cosmic microwave background radiation. Water vapor in the Earth’s atmosphere can severely interfere with observations. Therefore, detection experiments must be carried out in extremely dry and clean locations. The Qinghai-Tibet Plateau makes it difficult to even breathe, but it’s an excellent location for observing the universe.