Science is alive and kicking, but has not sci-fi fantasy done better?

摘要

'In the early morning hours of 30 June 1908, anyone happening to glance into the southeastern Siberian sky may have seen a fireball streaking through the atmosphere. That object, whatever it was, approaching from an azimuth of 115 deg and descending at an entry angle of 30 to 35 deg above the horizon, continued along a northwestward trajectory until it seemed about to disappear over the horizon. It would have seemed to shatter in a rapid series of cataclysmic explosions lasting about half a second over a distance of 15 to 20 kin. According to calculations, the object shattered at an altitude of 7.6 km and became the first such cosmic visitor to strike tile earth in the lifetime of civilized man.' That statenlent, culled fi'om the flood of information found in the 'Tunguska' sites on the Internet, clearly presumes that what happened was an extraterrestrial 'object' crashing oil the earth. Its weight has been estimated at about 100,000 tons and Ihe force of its explosion at 40 megatons (of TNT), 2000 times that of the fission bomb dropped over Hiroshima. By comparison, the explosive force of the 50,000-year-old asteroid strike that created the Arizona 'Meteor Crater' has been estimated at 3.5 megatons. (Incidentally, has anybody estimated the explosive force associated with tile formation of the Lonar Crater Lake in Maharashtra? What is the age of that event?)