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.