A bolide, or fireball, is an extremely bright meteor, and those can be about the size of a grapefruit.

火流星，或称火球，它是一种非常明亮的流星，大小和葡萄柚差不多。

As these inbound bolides approach the Sun, their ice sublimes, gas and dust escape, and a comet spreads its tail.

当这些冰块接近太阳时，冰块开始升华、形成气体和尘埃，一颗彗星就这样展开了它的尾巴。

If Earth were hit by something a bit bigger than the Chelyabinsk bolide, the damage could be immense.

如果地球被比车里雅宾斯克火流星稍大一点的东西击中，破坏可能是巨大的。

The first piece of this bolide was found the following day by the Wilcocks, a local family, shattered on their driveway (see picture).

第二天，当地家庭 Wilcocks 发现了第一块火流星，它们在车道上破碎了（见图）。

To test one possible answer to that question—hitting an incoming bolide with a suitably massive object and thus altering its trajectory—Nasa, America's space agency, has orchestrated a cosmic collision.

为了测试这个问题的一个可能答案——用质量合适的物体撞击一颗即将到来的火流星，从而改变它的轨迹——美国航天局美国国家航空航天局精心策划了一场宇宙碰撞。

The other, that the bolide's descent was captured in numerous photographs, both official (in the form of 16 dedicated meteor-tracking cameras) and unofficial (in the form of numerous vehicle-dashboard and doorbell cameras).

另一方面，火流星的下降被大量照片捕捉到，包括官方（以 16 个专用流星跟踪摄像机的形式）和非官方（以众多车辆仪表板和门铃摄像机的形式）。