【案例分析题】

According to people who saw it，a large，bright object ’exploded’over a.Siberian forest in 1908，making a very loud noise and causing a spectacular ’cloud of fire.’Surprisingly，scientists did not visit the area until 1927.If anything，they were expecting to find a large hole and fragments（碎片）of rock that would indicate the impact of a meteor（流星）.Instead，they found an area with fallen trees radiating（辐射）out from a central point，and largely destroyed by fire.Recent studies concluded that an object exploded about three miles above the ground.If this destruction was not caused by a meteor，then what did cause it？This is a tantalizing question.Some scientists think that a small comet（彗星）exploded just before colliding（碰撞）with the earth and ignited the forest.Recently，a few scientists have noticed that the area looks as if an atomic explosion took place，but they have no explanations of how or why.There is even a theory that a spaceship from another planet exploded while trying to land on the earth.To date，the evidence for all these theories is very mainly for educated guess.

It was surprising that （）.