/ 12 March 2007

SA scientists help astronomy team win top EU prize

South African scientists’ research on gamma rays has helped an international astronomy team win a top European Union award — and their technology could also be in your washing machine.

”We effectively stood in the shoes of people like Galileo,” said Professor Okkie de Jager of North West University (NWU) in Potchefstroom on Monday.

”We opened a new window on the universe, one that was not open before.”

De Jager and four other scientists at NWU are part of an EU-funded team of about 100, which runs the High-Energy Stereoscopic System (Hess) — four telescopes in Namibia used to research gamma rays.

The team won the prestigious EU Descartes prize for research for 2006, announced on March 7 in Belgium.

The Descartes prize is for trans-national teams, not individuals.

The Hess project was one of 13 finalists from 65 entries from about 20 countries.

”The High Energy Stereoscopic System … has revolutionised existing astronomical observation techniques and increased our knowledge and understanding of the Milky Way and beyond,” said the EU.

”With EU support they have designed and built the system, developed the complex software needed to collect and analyse data and offered training to young astronomers and astrophysicists.”

The gamma rays seen by Hess are of extremely high energies — a million times greater than an X-ray — and emanate from the resurrected remnants of stars that have died.

The Hess team pinpointed the source of these rays in the Milky Way, the galaxy that contains the Earth.

The rays cannot be seen with an ordinary telescope, so the team had to develop the Hess telescopes.

De Jager said the rays are so energetic that they cause a shockwave in the Earth’s atmosphere, which is seen as a blue disc of light called Cherenkov light. It is this light that the scientists measure.

When looking at the Milky Way, the astronomers are examining rays from remnants of stars which died anything from 1 000 to 50 000 years ago.

”What we see are stars that have exploded,” said De Jager.

”We find many new sources along the Milky Way.”

When a star explodes, it ”re-energises” its environment, leaving a rapidly rotating neutron star with a nebula.

The team takes pictures of these nebulae.

”We can really make out shapes … We see really funny shapes along the Milky Way that no one has seen before.”

Photographing them means using a camera shutter speed of a thousandth of a millionth of a second.

Hess also peers into distant galaxies ”from millions to billions of years old”, said De Jager.

He said the team’s work was groundbreaking.

”In the gamma-ray domain, the sky was very empty before Hess.”

Putting the Hess project together with the Southern African Large Telescope (Salt) in the Karoo and the Square Kilometre Array (SKA) gives astronomers a better overall view of the cosmos. The three projects research different wave spectrums — Salt views optical wavelengths, SKA radio waves and Hess gamma rays.

The work has useful spin-offs.

The team cannot bring these nebulae and black holes into the laboratory to examine, so scientists have to develop mathematical models and technology to simulate them.

”We develop mathematical skills and problem-solving techniques, which allow us to solve very difficult problems,” said De Jager.

Some of the mathematical and computer applications they develop are useful in finance.

”Many of our colleagues, locally and internationally, go to work in the financial markets afterwards.”

The technology they develop has uses elsewhere.

One of the more unusual benefits was the development of technology now used in ozone washing machines, which makes it possible to get a cleaner wash using cold water — a substantial reduction in energy use.

These novel technologies also open new possibilities for ultra-fast ignition systems in the automotive industry, which should result in cleaner combustion.

Now the team is working on Hess 2, a 30m telescope to join the other Hess telescopes in Namibia, and the Department of Science and Technology hopes to add more South Africans to the team.

The â,¬330 000 prize from the Descartes award is going towards building Hess 2.

”It will be the world’s largest reflector for astronomical purposes,” said De Jager.

The NWU team are De Jager, Professor Christo Raubenheimer, Christo Venter, computer specialist Matthew Holleran, Namibian astronomer Isak Davids and German post-doctoral astronomer Ingo Buesching.

The other scientists are from Germany, France, the United Kingdom, Ireland, the Czech Republic, Armenia and Poland and De Jager described them as ”the world’s best”. — Sapa