According to the lecture, the speaker casts doubts on the point in the reading passage that Mars is a planet where an organism exists.
First, in the reading passage, the writer mentions that the fact that Methane exists in the atmosphere on Mars has been proven by using sophisticated equipments. He asserts that the existence of it indicates that an organism called Methanogens thrives on Mars because Methanogens play a role of producing Methane. Furthermore, with having abilities living in extremely barren environment on the Earth, Methanogens can also live in Mars. Meanwhile, the lecturer says that contrary to the reading passage, Methane, being common all universe, cannot be an indication of the existence of an organism. He comments that with sources such as meteorites and volcanic activities producing Methane, it is hard to say that the existence of Methane is equal to a proof of an organism. Especially, with volcanic activities being the most noticeable feature in barren environment such as Mars, it is natural that Methane exists in Mars.
Secondly, in contrast to the argument in the reading passage that according to the research about a meteorite that fell from Mars to the Earth, the intricate crystalline structure, which can be made as a by-product through a process by bacteria, has been found, the lecturer argues that because the time for which the meteorite has existed after falling on the Earth has been guessed at about 3,000 years, it is possible enough for the meteorite to be contaminated by bacteria living on the Earth. Therefore, it is not sure that the structure was made by an organism living on Mars.
Finally, according to the reading passage, it seems clear that there should be an organism on Mars because the existence of the water, which is the most necessary material for organisms, can be guessed through the observance of hydrogen in the underground. However, the speakers asserts that since water is only useful to organisms in the form of liquid, the water on Mars, which exists in the form of ice, is not beneficial for them.
In summary, the lecturer maintains that it is hard to say that an organism exists on Mars based on the evidences ever established. |