21 February 2019
Chan Kwing-lam, the only Hong Kong representative at the 2006 assembly of the International Astronomical Union, was one of those who voted Pluto out as a planet of the solar system. Photo: HKEJ
Chan Kwing-lam, the only Hong Kong representative at the 2006 assembly of the International Astronomical Union, was one of those who voted Pluto out as a planet of the solar system. Photo: HKEJ

Why I voted that Pluto is not a planet: HK space scientist

Many may still wonder why Pluto is no longer considered a planet.

It’s a decision 411 scientists made during the 2006 general assembly of the International Astronomical Union (IAU).

Chan Kwing-lam, the only Hong Kong representative at the assembly, was one of those who voted Pluto out as a planet of the solar system.

“In fact, there are other Hong Kong scientists who are also IAU members. It just happened that they didn’t attend the meeting,” Chan said.

Under the IAU’s new definition, a celestial body must meet three criteria in order to qualify as a planet.

First, it has to be round.

Second, it has to orbit the sun.

Last, it has to be able to clear the “neighborhood” of its orbit.

This means that it has become gravitationally dominant in its orbital zone, which contains no other bodies of comparable size other than its own satellites.

“Pluto doesn’t meet the last criterion, so it is no longer a planet,” Chan explained.

The former researcher at NASA’s Goddard Space Flight Center understood the opposition of the public to Pluto’s removal from the roll of planets.

Pluto was long known as the ninth planet, and even Mickey Mouse’s pet was named after it.

Chan recalled that two or three other celestial bodies, which were more or less the same as Pluto, had been discovered in the Kuiper belt.

Those who discovered them wanted them upgraded as new planets in the solar family.

“This was a golden opportunity for fame, and so the idea was aggressively promoted,” Chan said.

However, it was not just a matter of two or three.

It was estimated that more than 1,000 such celestial bodies would be waiting to become planets if the new criteria were not put in place.

Pluto is still with us; only it is now regarded as a dwarf planet.

NASA’s New Horizons probe finally unveiled the mysterious Pluto with high resolution photos.

The spacecraft is performing another historic mission — it carries on board the ashes of Clyde Tombaugh, the US astronomer who discovered Pluto in 1930.

Netizens worried if aliens would take the ashes to clone Tombaugh.

Chan dismissed those fears light-heartedly, saying that if the aliens are capable of visiting Pluto, then they should visit Earth and catch a few specimens alive for fun.

He pointed out that the newly discovered celestial body “Earth 2.0″ is 1,000 light years away from Earth.

It’s simply not easy to arrive here, he said.

Pluto is not Chan’s main area of interest.

Mars is his true love.

He estimated that it would take only 200 years to terraform Mars for human settlement.

To Chan, now director of the lunar and planetary science laboratory at the Macau University of Science and Technology, the end of the world is not science fiction.

He has no doubt that day is coming closer.

“First, we are running out resources, and world wars will emerge as a result of it.

“Second, humans will be replaced by robots. The US says it is considering building an army of autonomous robots.

“Sooner or later, robots will develop emotions and free will with technological advances in artificial intelligence. They might kill you if they felt unhappy.”

Chan is also confident that highly intelligent aliens exist.

“Earth is very noisy with songs and music, emitting electromagnetic waves non-stop,” he said.

“It’s not difficult to locate us if they are capable of doing so.” 

There’s still some time before the arrival of apocalypse, and meanwhile Chan is exploring the possibility of using helium from the moon for solving Earth’s energy crisis.

In Chan’s opinion, Earth should not depend on fossil fuels any longer, as burning them causes temperatures to rise.

Solar power or wind power, however, is too weak to support the massive demand for electricity.

Electricity generated by nuclear technology is the only hope, he said.

Nonetheless, instead of existing technology using nuclear fission, nuclear fusion — a safer form – should be employed, Chan said, and researchers are trying to make it feasible.

This article appeared in the Hong Kong Economic Journal on Aug. 27.

Translation by Darlie Yiu

[Chinese version中文版]

– Contact us at [email protected]


Chan explained that Pluto doesn’t meet the third criterion to qualify as a planet, and so it is regarded as a dwarf planet instead. Photo: HKEJ

Chan (bottom right) was a former mathematics professor at the Hong Kong University of Science and Technology. Photo: HKEJ

Chan is seen with NASA astronaut Christopher Cassidy during an event at HKUST. Photo: HKEJ

Chan delivered a talk about China’s lunar exploration program at the Hong Kong Space Museum this month. Photo: HKEJ

Writer of the Hong Kong Economic Journal

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