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Scientists describe new telescope

This illustration shows the size of the ALMA telescope array under construction in Chile — up to 18km between antennas —by superimposing it on a satellite photo of the southern tip of Taiwan. PHOTO PROVIDED BY LIU SHENG-YUAN OF ACADEMIA SINICA

Answers to some of the astronomy world’s long-debated questions — such as the formation and structure of stars and galaxies when the universe was young — may soon be unveiled thanks to a groundbreaking collaboration involving Taiwanese astronomers, the National Science Council (NSC) said in a press conference yesterday.

The Atacama Large Millimeter/submillimeter Array (ALMA) observatory, a space telescope composed of 66 giant antennas scheduled for completion in 2012, and one of the world’s most advanced tools for exploring cooler parts of outer-space is almost complete, the NSC said.

The telescope — a collaboration between US, Canadian, EU, Japanese and Taiwanese scientists — successfully observed Mars in a “test drive” on April 30, ALMA project scientist Lu Sheng-yuan (呂聖元) said.

“This is a milestone for the extremely complex project — being in Chile’s Atacama desert 5,000m above sea level and involving so many mechanical components,” Lu said. “[Since 1995] we worked on producing, transporting and assembling the antennas, but we didn’t know if we would really see astronomical bodies through [the telescope].”

Taiwan’s contribution to the project — besides US$32 million in funding — is the development of the antennas, as well as the “front end,” the first electronic element through which the signals from space are received, Lu said.

The revolutionary space telescope is an interferometer, meaning that information collected by two or more of the antennas are processed into a single, high-resolution system, Lu said.

In the April 30 observation, two of the three completed antennas were spaced about 30m apart to collect signals from Mars, Lu said.

“This is kind of like detecting a person’s location from listening: With one ear, it is difficult to detect where the person is talking from, but with two it is easier,” he said.

When all 66 antennas are completed, the distance between them will be able to be adjusted according to the resolution the scientists desire, Lu said.

“The longer the distance between two antennas, the better the resolution, but the smaller a region we can observe. The maximum distance two antennas can be placed apart is 18km, which would simulate the effect of a [traditional] telescope 18km in diameter,” he said.

In addition to being very high resolution, the wavelengths that the antennas detect enable scientists to observe cooler parts in the universe, meaning galaxies and stars that are at early stages in their formation, Lu said.

“This means we can explore the formation of them, and confirm or reject current theories,” he said.

As for the future of the project, Lu said that Taiwanese researchers are entitled to up to 60 percent of the telescope’s observation time when it is completed, pending researchers submitting good proposals.

However, he is optimistic that the nation’s scientists can get sufficient time with ALMA: “Though we are a young team, I don’t think our [quality of research] would be worse than other countries.”
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