Recently, Professor Sun Daoyuan and Professor Mao Zedong's team from the University of Science and Technology of China, together with foreign scholars, have made significant progress in the field of planetary science research. The research team has confirmed for the first time the existence of a solid core with a radius of about 600 kilometers inside Mars through in-depth analysis of fire shock data recorded by NASA's Insight probe, and revealed that its main component may be a crystalline iron nickel alloy rich in light elements. This achievement was recently published in the international academic journal Nature. Mars, as the most Earth like planet in the solar system, has always been an important object of research on the internal structure and evolution of planets, and is also one of the core targets of deep space exploration. The exploration of the deep structure of planets has always been challenging. Taking Earth, which is most familiar to humans, as an example, scientists did not speculate on the existence of a solid core for the first time until 1936 through seismic waves. It took nearly half a century to fully confirm the existence of a solid core, which was not completed until the 1980s. In contrast, exploring the internal structure of Mars is more difficult, and direct observation data of Martian earthquakes was only obtained for the first time in 2018. Up to now, although thousands of seismic data have been recorded, issues such as weak signals and noise interference still severely limit research on the deep structure of Mars. To overcome this challenge, the research team innovatively introduced the fire shock array analysis method. Through the analysis of 23 high signal-to-noise ratio fire shock event data, the key seismic phases passing through the Martian nucleus were successfully extracted. The propagation speed of seismic waves in solids is faster than in liquids. Actual observations have shown that the Martian nucleus has a layered structure, with the outer layer being a liquid core and the deeper part having a higher velocity solid core. In further analysis, the research team identified for the first time seismic phase signals considered as "solid core markers" in fire shock data, providing evidence for the existence of a solid core on Mars. Based on different seismic phases, the team measured that the solid core radius of Mars is about 600 kilometers, accounting for 1/5 of the radius of Mars, and the ratio of its inner and outer core structures is close to that of Earth. The research team further analyzed the mineral composition of the core. It was found that the Martian nucleus is not composed entirely of iron and nickel, but may contain 12% to 16% sulfur, 6.7% to 9.0% oxygen, and no more than 3.8% carbon. This core structure containing light elements not only provides important clues for the evolution of Mars' magnetic field from early activity to current silence, but also lays a key foundation for comparing the internal evolution differences between Earth and other terrestrial planets. This study confirms for the first time the existence of solid cores in planets outside of Earth, confirming the similar nuclear mantle differentiation structure between Mars and Earth. The innovative development of Martian seismology methods by the research team provides important reference for using seismology methods to explore the deep structures of celestial bodies such as the moon in future lunar exploration missions. At the same time, this achievement marks a crucial step forward for Chinese research teams in the field of planetary internal structure exploration, demonstrating China's innovative capabilities and international influence in the intersection of planetary science and geophysics research. (New Society)