我们为什么要去撞击小行星（院士讲科普）

Core Viewpoint - The article discusses the significance of asteroid exploration, defense, and resource utilization, highlighting the potential threats posed by near-Earth asteroids and the need for international collaboration in addressing these challenges [4][7][10]. Group 1: Asteroid Characteristics and Distribution - The solar system contains billions of asteroids, categorized into near-Earth asteroids, main belt asteroids, Trojan asteroids, centaur asteroids, and Kuiper belt asteroids, serving as "living fossils" of solar system formation and evolution [5]. - Near-Earth asteroids are defined as those with a perihelion distance of less than 1.3 AU, and they are rich in resources such as iron, nickel, platinum group metals, and water ice [5][6]. Group 2: Exploration and Defense Initiatives - Japan's Hayabusa mission successfully returned samples from the Itokawa asteroid, while China's Chang'e 2 conducted a flyby of the Toutatis asteroid, showcasing advancements in asteroid exploration [6]. - The U.S. has successfully implemented kinetic impactor missions, such as the DART mission, to test the feasibility of altering asteroid trajectories [6][7]. - China plans to launch the Tianwen-2 mission to sample a near-Earth asteroid by May 2025, furthering its capabilities in asteroid exploration and defense [6][9]. Group 3: Threats Posed by Asteroids - Near-Earth asteroids are considered one of the most significant potential threats to Earth, with historical events like the Chicxulub impact leading to mass extinctions [7]. - As of March 2025, 38,171 near-Earth objects have been discovered, but only a small fraction has been cataloged, indicating a need for improved monitoring and tracking systems [7][8]. Group 4: Resource Development Potential - Asteroids hold significant economic value, with estimates suggesting that over 700 of the 1,000 well-studied asteroids could each be worth over $100 trillion, and the total value of main belt asteroid resources could exceed $70 trillion in the next 30 years [11]. - The development of asteroid resources involves a series of activities including exploration, extraction, processing, and transportation, potentially leading to a "space supply chain" [10][11]. Group 5: International Collaboration and Future Plans - China has proposed a comprehensive strategy for asteroid detection and defense, emphasizing the need for a collaborative international approach to build a robust asteroid monitoring and defense system [8][9]. - The planned demonstration of kinetic impactor missions aims to validate the technology's effectiveness in altering asteroid trajectories and ensuring Earth's safety [9].