Like ghosts in the air, UFOs are mysterious and varied. There have been discussions and controversies for decades about the existence of UFOs. Some scholars assert a UFO is an optical illusion, while others think UFOs do exist as objects. So, exploring UFO phenomena is really an interesting matter.

What stage is China at in the study of UFOs? Is there any cooperation with international colleagues?

China is already walking in the forefront of international UFO research and exploration. At present, with plenty of credible, verifiable observation reports, China has entered a quantitative analysis stage of study. We also carried out academic exchanges with colleagues all over the world.

How do you conduct UFO research and what tools and methods do you employ? Can you tell us something about your research achievements?

In order to overcome the difficulties in UFO study, I introduced quantitative analysis methods into the field. In the last 39 years, based on my work at the PMO and my personal observation experiences, I have made quantitative analysis of some of the great UFO events by employing spherical astronomy and physics.

In the past decades, a large number of experienced astronomy amateurs have appeared in China. They are scattered throughout the country, and form an efficient observation network. Once a UFO event occurs, the PMO where I have been working will receive huge amounts of observational data from amateurs.

As for me, with years of field observation experience and six years of study in astrophysics at Peking University, I can figure out flying height, direction, and speed and the position of substellar point (the point on the earth at which the star is in the zenith at a specified time) by employing spherical astronomy methods based on several high quality sighting reports about a UFO event from different locations with sufficient distance, and analyze the mechanism of the event by physical methods.

Since 1971, I have been engaged in conducting in-depth investigations and quantitative and semi-quantitative scientific analysis to at least 20 spiral, fan and light-like UFO events. I found many strange flying objects appeared at a speed much lower than first cosmic velocity in the space between 130 km to 1,500 km from the Earth's surface. Some even flew at a speed as low as 0.29 km a second, 4 percent of the first cosmic velocity at the flying height, and flew at the height of around 1,460 km for 25 minutes. The facts show those UFOs may possess anti-gravity ability, or they would have fallen to the Earth.

I classified the more than 100 typical UFO events that occurred in the last 39 years into 10 or so types. I paid more attention to UFO events observed at the same time but from more than two different locations. I found seven types of these events could be explained through existing natural phenomena and knowledge, including objects that look like bolides, light spots, bright constellations, flying point clusters, bright stars, or flying sticks. Eight types still cannot be explained from existing knowledge, including spiral-, fan-, spindle-, ball-, or V-shaped objects, or those that look like balls of lightning, strange vehicles or flying saucers, of which spiral-, fan-, light ball- or flying saucer-shaped objects may be related to extraterrestrial craft.

What do you think we should do to further the exploration for UFOs?

Designing and manufacturing a new type of special telescope is very necessary. As a UFO is only met by chance and disappears rapidly, a special telescope with a small aperture may be better for observations. More such telescopes should be made and installed in different observation stations, so as to form an observation network. Once a UFO appears, immediate and networked observations would be carried out, thereby achieving a leap in observation accuracy, depth and quality. At the same time, more accurate quantitative analysis should be employed on the basis of observation.

For human beings, what is the significance of UFO studies?

First, we hope to explore extraterrestrial civilizations. If we find solid evidence about alien spacecraft visiting the Earth through further observation and analysis, it would be as significant as Columbus Christopher's discovering the New World. Second, we need to explore unknown natural phenomenon and laws. Third, it would be of great significance to national defense and economic development. Fourth, finding out the truth about UFOs would also be helpful for dispelling the public's superstitions and misconceptions.

At present, scientists do not have any concrete evidence about aliens. But many scientists believe aliens exist. Does this mean the question is not whether there are aliens, but when they will contact us?

Yes. Astronomers all over the world are now intensifying their efforts to explore extraterrestrial life and civilization. As long as we have open minds about scientific exploration of the unknown and employ multiple methods, the contact between humans and extraterrestrial life will hopefully come this century.