Core Points - Chinese scientists successfully detected a laser signal reflected from a 10-centimeter diameter retroreflector on the Moon, marking a significant achievement in space exploration [1][4] - This accomplishment makes China the fourth country to complete such measurements, following France, Germany, and the United States [4] - The new generation of lunar retroreflectors offers higher precision compared to previous models, despite being more challenging to observe due to their smaller size and weaker signals [6][8] Group 1 - The laser echoes were received from a set of retroreflectors installed on the lunar surface, which serve as reference points for measuring distances in space [3] - The measurement process involves sending laser pulses from ground observation stations to the retroreflectors and calculating the time taken for the pulses to return [3] - The difficulty of detecting such a small target from a distance of approximately 380,000 kilometers is likened to finding a grain of sand on an aircraft carrier's deck [8] Group 2 - The "Tianqin Project" aims to continuously collect data from the retroreflectors to accumulate high-precision Earth-Moon distance measurements [10] - This data will be used for research on gravitational forces, the evolution of the Earth-Moon system, and will lay the groundwork for future gravitational wave detection in space [10]