The content of the reading and the lecture is about one of the largest explosions in history – the explosion in Tunguska in 1908. The reading supports the idea that it was a massive methane gas explosion while the lecture argues that it was an asteroid strike which caused the explosion. According to the reading passage, the fact that no rocks or material from an asteroid have been found and nobody witnesses an asteroid streaking across the sky means that there is no evidence of an asteroid strike. However, the lecturer claims that people saw the bright in the sky which could have been an entering of asteroid into the atmosphere.
Moreover, there were huge explosion and great wind which looked like an aftereffect of an asteroid strike. The reading points out that an asteroid leaves a huge impact crater which has not been found in Tunguska. The writer also mentions that a large area of forest was damaged which is likely to be a methane explosion. Reversely, the lecturer explains that the asteroid exploded in the air so that rocks and impact craters could not be found. Besides that, trees below the explosion only missed leaves and branches, which is similar to an asteroid hit.
The writer explains that the level of methane gas in the air is really high. It might have been released and then exploded. Another probability is that lightning which was witnessed nearby could have made the explosion. Contrary to the reading, the lecturer argues that the explosion in Tunguska needs an enormous amount of methane gas which cannot be found in this place. He also says that a gas explosion must create fires which were not recorded in that area. In conclusion, the lecturer regards the asteroid strike as the cause of the explosion while the reading claims the explosion was a methane gas one.