研究分析了三大天文台汇整的引力波暂态目录，共有 153 次可信的黑洞合并侦测，其中 34 次属于特别沉重的系统。结果显示，较轻的黑洞质量最高约到 40 个太阳质量，通常具有较小且彼此对齐的自转；但在约 45 个太阳质量附近出现另一个族群，其自转更快、方向更混乱，这种统计特征最符合「二代黑洞」——也就是先前合并后再度参与碰撞的产物。
整体趋势表明，最重的黑洞不是「出生」而是「建造」出来的：它们在致密的星团中经由多次碰撞逐步累积。自 2015 年首次侦测到黑洞合并以来，引力波仪器已证实这类碰撞比过去想像更常见，而这些碰撞所留下的时空震荡，提供了无法直接在 X 光或可见光中观测到的质量证据。
The study argues that a population of “impossible” black holes is likely assembled through repeated mergers rather than born in a single stellar collapse. Ordinary stellar black holes are about 10 to 40 solar masses, while supermassive black holes reach millions to billions of solar masses; the disputed middle range, roughly 40 to 100 solar masses, is too massive for direct stellar death yet too small for formation from a gigantic gas-cloud collapse, making it a long-standing anomaly in stellar physics.
Researchers analyzed a transient gravitational-wave catalog from the world’s three leading observatories, containing 153 reliable black-hole merger detections. Of these, 34 involved particularly heavy objects. The data separate into two populations: lighter black holes, up to about 40 solar masses, with small aligned spins, and a heavier group emerging around 45 solar masses with rapid, chaotic spins—a statistical marker consistent only with prior merger history.
The overall pattern suggests the heaviest black holes are built, not simply born, in dense star-cluster environments. Since the first merger detection in 2015, gravitational-wave observations have shown these collisions are more frequent than once thought. Because such objects are invisible in X-rays and visible light, their masses are inferred from spacetime vibrations, offering the key evidence that stellar theory alone cannot explain their origins.