当火球冷却时，内部的气化物质压缩形成固态微粒云。
As the fireball cools, the vaporized materials in it condense to form a cloud of solid particles.
热与冰的交互作用把岩浆雾化成比通常的火山灰更为纯净的微粒，同时，它产生的蒸气云把火山灰送到了比通常更高的高空。
The interaction of heat and ice atomized the magma into much finer particles than is typical, and created a steam cloud that sent the ash higher than usual into the air.
人们认为这些离子有助于产生被称作气溶胶的各种新微粒，而且当气溶胶的体积增大到一定规模，它便成了云滴形成的“温床”。
These ions are thought to help create new particles called aerosols and, when aerosols grow above a certain size, they become the seeds around which cloud droplets form.
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