The streaks that cut diagonally across them are " fireballs . "

斜穿过它们的条纹就是“火球”。

Firefighters spent four hours trying to seal the gas pipe , as orange fireballs spewed from a factory building roof .

消防员花了四个小时试图封堵输气管道，橙色的火球从一幢工厂建筑的屋顶中喷出。

It seems at least three individual fireballs were seen on the night of 16 may 2006 .

据说2006年5月16日晚人们看到了至少三个不同的火球。

For another , the artificial fireballs seem to be glowing because of the excitation of theatoms within the vaporised material rather than because of oxidation .

另一方面：人工的火球看起来炽热的是由于在蒸汽态的原子的激发而导致，而不是由于氧化。

His idea is that one of the fireballs may have momentarily triggered an electrical connection between the upper atmosphere and the ground , providing energy for the ball lightning to appear above the hills .

他认为这些火球中的一个可能瞬间造成了高层大气与地面之间的回路，形成了出现在山顶的球状闪电。