WHEN two glowing UFOs appeared to be rushing at high speed to the just-launched Shenzhou-9 spacecraft earlier this month, the man reporters rushed to call was 73-year-old Wang Sichao, noted astrophysicist and expert on exotic unidentified flying objects.

Ever ready to expound on close encounters of the third kind, Professor Wang studied the TV footage and said they might have been two moths close to the camera or possibly conventional aircraft passed by the rocket.

No alien UFOs this time, but Wang, an expert on meteorites and formation of the solar system, has dedicated the past 40 years to analyzing UFO reports in China.

His conclusion: Alien UFOs definitely have been sighted around China. He says he's sure because his calculations of their location, altitude, speed and other factors indicate craft employing technology far beyond anything known to man at this time (unless, as conspiracy theorists around the world say, it's supersecret government tech). And he has excluded conventional aircraft, rockets, satellites, weather balloons, birds, insects, meteorites, comets, meteorological phenomena and so on.

Wang is China's best known - and lone - expert voice asserting the likelihood of extraterrestrial visitors, and he has taken a lot of heat from the public and some astronomers. People call Wang a dreamer so biased and obsessed with alien life that he sees an alien presence in many UFOs that have other explanations. He's the old man playing hide and seek with ET.

But as elsewhere in the world, China is filled with Trekkies and UFO true believers and he has a big following. Airports have been closed over the years because of UFOs.

"I am 100 percent certain. There have been UFO sightings that must have been alien space craft because they cannot be explained any other way," Wang told Shanghai Daily in an interview this month at his home in Nanjing. He was a researcher for decades at the Nanjing Purple Mountain Observatory under the Chinese Academy of Sciences. He still uses facilities.

"Many scholars hate things they cannot explain since they only believe in high-tech, not eyewitness reports," said Wang who has amassed and analyzed thousands of UFO sightings, detailed descriptions, photos and diagrams using star chart plotting.

"But the fact is we are probably confronting entirely new things we have never encountered before, and we can't explain them with known technologies alone."

Wang is the media's go-to guy when it comes to UFOs and extra-terrestrials. He's always good for a quote promoting his theories of intelligent life in the solar system and beyond.

These days Wang researches, collects and analyzes reports of sightings.

He was in the news recently when he suggested on June 19 that the two UFOs captured on camera near the Shenzhou-9 spacecraft could have been moths or aircraft that had passed the no-fly zone near the launch area. (Shanghai Daily June 20 "Moths may have been space launch UFOs")

Nobody knows exactly what they were. The government has no response.

During a rash of UFO sightings in China last year, Wang declared that the glowing, expanding ball that appeared in the sky high above Shanghai on August 20 was an alien spacecraft. There were sightings in Beijing and in Anhui Province and several commercial aircraft pilots blogged about seeing them.

He called it one of the 20 most significant alien UFO sightings in China in the past 40 years.

Some astronomers were baffled, some linked it to the launch of an intercontinental ballistic missile in California and the diffusing gas of thruster rockets.

Nobody knows for sure. The East China Air Traffic Control Bureau, which almost never comments, said it was unable to provide an explanation.

In his database at home, Wang catalogues hundreds of supposed eyewitness reports of UFO sightings across China each year. He calculates the objects' altitude and speed, trying to analyze their propulsion and other systems. He uses the positions of the stars in calculations. He says many flying so high above the earth but moving at such a slow speed that they would fall because of gravity if not kept aloft by spinning at an extraordinary speed, which cannot be achieved by man-made craft.

Because of his UFO pronouncements, Wang has stirred waves of controversy and appeared in TV face-offs. Debate swirls on the Internet. He was famously assailed in a TV showdown in 2005 by China's famous "science cop" Fang Zhouzi, a self-proclaimed fighter against pseudoscience. Fang refused to look at any of Wang's evidence or calculations.

None of this has slowed Wang down.

"If we can find exact evidence through discovery and calculation showing that alien spacecraft have visited the earth, we may have written a new page of human history," Wang said.

"This is like Columbus discovering the New World," he said with a grin in his mountainside apartment overlooking Nanjing in Jiangsu Province.

Early days

As his parents fled on foot from advancing Japanese troops in July 1939, a baby boy was born along the way in eastern Guangdong Province. Holding her son and looking back at the roads they traveled, his mother said she was already homesick for her occupied hometown of Chaozhou.

The boy born near a battlefield was named Wang Sichao, Sichao literally meaning "Missing Chaozhou."

"In the hard early days of my childhood, I learned how to be tough," Wang said, adding that a thick skin helps him endure criticism and ridicule.

Wang became interested in aliens in middle school when the teacher asked students to imagine what Martians would look like.

"It was a very funny topic," Wang recalled. "My classmates thought that they must have very big feet so they can stand on the planet where gravity is weak. Some said they must have very big noses with thick nasal hairs because the air quality is bad."

That got him thinking about life elsewhere in the solar system and beyond. He stared at the night sky and read science fiction about UFOs and aliens.

In 1957 Wang got the top score in Guangdong Province on the National College Entrance Exam and enrolled in Peking University, majoring in physics and then astrophysics.

In 1970 he became a researcher at Purple Mountain Observatory, specializing in meteorites and the origins of the solar system. He has gone on solitary expeditions and brought back meteorites, including one piece older than Earth itself (generally accepted to be around 4.5 billion years old). That came from the world's largest observed meteorite shower on March 8, 1976, in Jilin Province.

But it was not until he received two strange reports about a UFO sighting on September 26, 1971, that he became fascinated by aliens. At the time he was studying meteorites and asked the public to write to him when they spotted meteorites.

"But many people don't know what meteorites are (they are meteors that strike the earth) so they wrote whenever they saw strange things in the sky," he said. He received two letters from different parts of Yangzhou City in Jiangsu Province about a sighting around 7pm. Two villagers saw a round, luminous object, as big as a full moon, silently spinning, hovering and moving in a spiral for 10 minutes - then it vanished.

"It was the first time that I encountered such strange astronomical phenomena," Wang said. "I couldn't come up with any scientific explanation, but I was anxious to know why it occurred."

He made a rough calculation based on witnesses' letters and found the object was flying at an altitude of several hundred kilometers. To reach that altitude, the object had to be flying at around 8km per second. But at that speed, the object would disappear in a blink and couldn't remain in place for so long, he reasoned. But without better data, he had to give up his investigation, deciding to wait for a reappearance.

He waited 10 years, studying meteorites.

In July 1981, more than 70 people across China wrote to him saying that on July 24 they had witnessed a round, luminous, spinning object; it hovered in one place, expanded dramatically and disappeared.

Some astronomers recorded the object and drew its path on star charts. There were witnesses from Inner Mongolia Autonomous Region, Yunnan, Shanxi and Henan provinces. Wang read all the reports and said they corroborated each other.

Witnesses spotted the bright ball of light late at night, moving from southern Inner Mongolia westward to the southern Xinjiang Uygur Autonomous Region, covering nearly 2,000km. It was sighted for about 30 seconds above Gansu Province, then its middle section began to spin and it moved on.

"These witness reports were of great significance because reports from different areas, angles and elevations enabled me to calculate the UFO's altitude and speed," Wang said. "It was one of the most exciting moments of my life."

After days of figuring, Wang placed it around 650km above the earth and flying at a speed of only 1.6km per second, far slower than what's called first cosmic velocity, 7.9km per second, the speed necessary to resist gravity. It was moving in an expanding spiral and spinning at a super high speed to remain in position, he said.

"This means the object could be an alien spacecraft since no man-made craft can fly so high at such a low speed," Wang said. "As it was spinning, the craft probably displaced gas and tiny luminous particles from all directions so it also appeared to be swirling."

That was the first time, in 1981, Wang publicly said alien UFOs likely visited Earth and he spent the rest of his life studying them.

In 1991 he got more than 50 reports of a "huge ghostly eye" above Henan Province on July 25. It appeared six times larger than a full moon. One witness drew it on a star chart so Wang could calculate altitude and speed.

On October 19, 1998, Wang interviewed a military pilot at an airbase in Cangzhou City in Hebei Province, and the man said he pursued a "flying saucer" late at night until he had to turn back or run out of fuel. He said the objects' lights appeared to be solid and did not dim or fade with distance.

Wang has become a lightning rod for criticism, as are all high-profile UFO hunters everywhere.

"I welcome doubts and debates because people can dispute my calculations," Wang said, "but many people attack me without any scientific evidence, they simply don't like things they cannot explain.

"I'm not afraid of being laughed at since I am working on something entirely new to the human race."

He conceded there's a lot of disappointment in UFO research, but said, "It's worth the effort as long as I can contribute a little on the way to finding aliens."