It is for this that this year's US$1 million Shaw Prize in Astronomy was given to Jewitt while professor at the University of Hawaii, and his then graduate student Jane Luu, now a technical staff member at the Massachusetts Institute of Technology.

The Shaw Prize - established nine years ago by Hong Kong's TVB founder Run Run Shaw to award prizes for astronomy, life science and medicine, and mathematical sciences - is known as the Asian Nobel.

The citation describes the work by Jewitt and Luu as an 'archaeological treasure', an apt description given it took the duo five years pointing the telescopes everywhere, but finding very little.

Jewitt said he was 'extremely honoured to win the Shaw Prize'.

'You know that science advances basically by proving that what everyone believes to be true is wrong. It moves forwards by shooting things down,' he told the Sunday Morning Post.

'For that reason, it's normal that everything you do as a scientist comes under attack. The environment is generally critical and sometimes that criticism spreads and becomes personal.

'Getting a prize is exactly the opposite. I think I'm not really able to deal with it.'

Luu, who could not be reached for comment, told learning website Imagiverse about winning the prize.

'I'm pretty proud of it because we stuck with it for a long time - five years!' she said. 'Everybody kept saying, 'When are you guys going to quit? It's hopeless. It doesn't exist!' So in terms of scientific accomplishment, that discovery has been my biggest accomplishment.'

Jewitt said the discovery 'completely changed our perception of the solar system by, for instance, showing where the comets come from, showing that the outer regions are full of the most primitive bodies in the solar system, and that the planetary orbits expanded, meaning that the planets did not form where we now find them. This latter result has triggered a burst of computer models of the evolution of the system that are quite different from models before we knew of the Kuiper belt.'

Covering the area from Neptune - the farthest planet - to 50 astronomical units (AU), the Kuiper belt hosts a lot of space objects, remnants from the solar system's formation.

An AU is the distance between the sun and earth, roughly 149 million kilometres.

It is similar to the asteroid belt, but instead of being composed of mainly rock and metal, most of its bodies are frozen volatiles - methane, ammonia and water.

More than 70,000 such icy bodies are believed to exist in the outskirts of the solar system.

These objects were valuable because they were 'the most primitive material to be found in the solar system, formed when the solar system was born' in a way the Big Bang theory suggested, Jewitt said.

The finding had helped scientists learn things that were beyond what they had dreamed, Luu said.

For instance, Pluto's status changed from a planet to a big object in the outer solar system. 'What we thought of as a planet is probably just the biggest member of a rather large population of objects,' she said.

More remains to be seen. Nasa launched the New Horizons mission in 2006 to Pluto and the Kuiper belt - the first time a spacecraft has been sent to an unexplored world since the Voyager 2 craft visited Neptune in the late 1980s.

The billions of kilometres New Horizons must cross to reach Pluto means it will not arrive until July 2015. It is cruising towards Pluto now and connects to Nasa occasionally for technical checks.

For Jewitt, the discovery was the highlight of a vocation that he has pursued since childhood.

For Luu, though, it was an unforeseen development in a mercurial career that has taken her from war-torn Vietnam to professorship in the US and the Netherlands.

'My parents don't know any science at all - they were not educated,' she said. 'So they are proud of the fact that I have a doctorate. They've seen I've achieved some sort of name for myself, for they see me in the magazines, the newspapers, and sometimes on TV. So they think it must be good. They don't understand what I do but they think, 'Well, she must have done something good.''

A Vietnamese-American who grew up in South Vietnam and fled to the US as a refugee aged 11, Luu quit academia to work on satellite instruments at MIT's Lincoln Laboratory.

'I'm not going observing any more, but I'd like to go back to astronomy eventually,' she said. 'I left academia. I'm no longer a professor. The reason I did that was I wanted to come back to the States and I didn't want to get back into the rat race of academia. Hard work is OK, but academia is very restrictive.'

Jewitt said his greatest satisfaction being a scientist came from 'seeing things that nobody saw before, or [measuring] something that nobody measured or thought to measure'.

'This is like walking forwards in a darkened room full of smoke. I fall down. I get lost. But sometimes I bump into things that turn out to be interesting, things that I could not have guessed would be there.'

6.6b

Number of kilometres Jewitt's discovery of 1992 QB1 was from earth, which paved the way for the finding of more than 1,000 such objects