After half a month, he returned to Tucson again. Sun Cheng seemed more cautious than before.

    "University of Arizona? Don''t let me down..."

    Quietly through the night, he lurked near the campus of the University of Arizona. While detecting the distribution of monitors near the school, sun Cheng calmly looked for a location convenient for him to invade the school.

    Before returning to Tucson, he spent two days in Carson, the capital of Nevada.

    In the past two days, sun Cheng was busy looking for clues about [ignition source] and invaded the Internet many times.

    He not only searched all the records of meteorite disasters recorded in American history, but also took great pains to find all kinds of news related to "haunted" and "robot" on the Internet.

    But to sun Cheng''s disappointment, he failed to find any commotion caused by [ignition source] on the Internet.

    However, he did not find anything suspicious. Sun Cheng found a suspicious clue in the investigation of the meteorite.

    As one of the countries most attacked by meteorites on earth, the United States has kept a wealth of records on meteorite landings in various states. Many small meteorite craters are equipped with professional investigation records, but it is only vague about an investigation called [balinger crater], which immediately aroused sun Cheng''s suspicion.

    Patiently following the suspicious point, he felt more and more strange.

    According to sun Cheng''s investigation, [balinger crater] is often called [Arizona crater]. It is located in a desert in Arizona. It is a huge crater with a diameter of 1.2km and a depth of 180m. It is suspected that it was formed by a huge meteorite hitting the earth 10000 years ago.

    There are many introductions about it on the Internet. For example, some geological experts believe that the mass of meteorites that hit the desert in Arizona is estimated to be several million tons. The impact speed into the earth''s atmosphere is between 10 ~ 20 km / s, and about 10 million tons of TNT equivalent is released during the impact, which is as powerful as a large equivalent hydrogen bomb.

    It is reasonable that meteorites of this scale hit the earth once in a thousand years.

    Even though the baringer crater was created 10000 years ago, there is no reason why the U.S. government sent a large number of experts to study the small meteorites that fell in the territory in recent 100 years, but did not study it.

    But the result of sun Cheng''s careful investigation is that he only found that more than 90 years ago, that is, in 1912, the University of Arizona sent a scientific research team at its own expense to investigate the baringer crater.

    Besides, what did the scientific research team find? Who are the members? Did you find meteorite fragments and so on?

    I can''t find any of these on the Internet!

    That''s interesting!

    The largest meteorite crater in the United States, but I can''t submit a detailed investigation report. Even in recent decades, I can''t find the news that the U.S. government has sent more experts to investigate it!

    Moreover, this [balinger crater] is still located in Arizona. Based on Sun Cheng''s understanding of the treacherous Starscream, he will never place the base on the outskirts of Tucson, Arizona, without any reason.

    Unable to find more information on the Internet, sun Cheng had to venture back to Tucson to sneak into the University of Arizona to see if he could find more analysis reports on baglin crater.

    This is undoubtedly a very risky move!

    Yes, after the attack on Davis Mengshan Air Force Base on the outskirts of Tucson and the theft of four nuclear warheads, although the U.S. government kept silent, it has never relaxed its investigation into the whole matter.

    In addition, he was not sure. Anyway, sun Cheng felt extremely irritable before he was close to Tucson. An indescribable uneasy feeling was constantly warning him.

    When he sneaked into the city, he saw the armed infantry vehicles and helicopters of the National Guard frequently haunting the streets and alleys, and it was even more common for the police to patrol.

    Therefore, sun Cheng is also cautious and cautious, lest he make a mistake.

    [spy template] after quickly capturing all the monitoring equipment information nearby, sun Cheng looked around. When he found a big tree not far from the school yard wall, his eyes lit up.

    Quietly touched under the tree, sun Cheng jumped onto a branch on the tree. Then he jumped again with the help of the branch. When he landed again, he had entered the campus of the University of Arizona.

    [University of Arizona] is the state of Arizona. Thank the readers of "purple night devil" and "drtgrt" for their great rewards.