热辐射密度以核爆点距离平方倒数的速度衰减，爆炸、冲击波、致电离辐射效应的衰减速度则更快。
The intensity of thermal radiation decreases only as the inverse square of the distance from a nuclear detonation, while blast, shock, and prompt ionizing radiation effects decrease more rapidly.
斯皮策望远镜上的红外线设备可以俘获环尘埃发出的热辐射，这个巨大的环内侧距离土星600万公里，向外一直扩展到1800万公里处。
Spitzer's IR instruments can capture the heat radiation put off by dust particles in the ring, which starts some 3.7 million miles from Saturn and extends outward another 7.4 million miles.
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