Professor Stephen Hawking warns us not to attempt to contact aliens, but in the last few months throughout China, it might appear as though aliens are trying to contact us, as several unidentified flying objects (UFOs) have been spotted.

A hand-drawn picture of the UFO observed in Sichuan in July 1981. The UFO was spotted in 14 provinces.

"About 96 percent of the universe remains a mystery to human beings. We should be open to unknown things," Professor Wang Sichao said.

According to Professor Wang, a researcher of the Purple Mountain Observatory of the Chinese Academy of Sciences, China may witness more UFOs sightings in next two years.

After years of research, Professor Wang discovered that major UFO sightings tend to occur in years ending with numbers 1, 2 or 7.

So there you have it, 2011 and 2012 are UFO years. To optimize your chances, the professor recommends July and August as the best months and viewing after 10 p.m.

After 39 years studying UFOs, Professor Wang concludes that most reports have been hoaxes. The objects spotted were mostly missiles, satellites and meteors. Yet, he admits a few cases still can't be explained, and these could be actual encounters with alien intelligence.

Since June 30, at least eight UFO sightings were reported in Xinjiang, Hunan, Zhejiang, Chongqing and other parts of China. Some of the objects later turned out to be rockets, planes or lighted kites. Yet, some remain a mystery.