China unveils Asia's biggest radio telescope

Last Updated: Sunday, October 28, 2012, 19:39

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Tags: Radio telescope, China, Radio astronomy

Beijing: China today unveiled Asia's biggest radio telescope to be used in collecting accurate data from satellites and space probes.

The 65 meter diameter telescope was unveiled at the foot of Sheshan Mountain in Shanghai.

The sprawling telescope with the size of about 10 basketball courts can pick up eight different frequency bands and also track Earth satellites, lunar exploration satellites and deep space probes, official media here reported.

"We hope that the new radio telescope will go into operation earlier so that we can use it to observe the unmanned lunar probe Chang'e-2," Wu Weiren, chief designer of the lunar orbiter project said.

The telescope will be used for Very Long Baseline Interferometry (VLBI), a type of astronomical interferometry used in radio astronomy, as it can collect accurate data and increase its angular resolution during astronomical observation, state run Xinhua reported.

China's VLBI system is made up of four telescopes in the cities of Shanghai, Beijing, Kunming, Urumqi, respectively, as well as a data center in Shanghai.

Radio telescopes differ from optical ones in that they use radio antennae to track and collect data from satellites and space probes.

The first radio antenna used to identify astronomical radio sources was built by American radio engineer Karl Guthe Jansky, an engineer with Bell Telephone Laboratories, in the early 1930s.

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Bacteria that function as living electrical cables found

Last Updated: Thursday, October 25, 2012, 21:52

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Tags: Bacteria, Electrical cable, Aarhus University

Washington: Danish scientists have discovered that some bacteria form a kind of gigantic power lines to survive between the different layers of marine mud.

Researchers at Aarhus University, Denmark, made a sensational discovery almost three years ago when they measured electric currents in the seabed.

It was unclear as to what was conducting the current, but the researchers imagined the electric currents might run between different bacteria via a joint external wiring network.

The researchers have now solved the mystery. It turns out that the whole process takes place inside bacteria that are one centimetre long.

They make up a kind of live electric cable that no one had ever imagined existed. Each one of these 'cable bacteria' contains a bundle of insulated wires that conduct an electric current from one end to the other.

"Our experiments showed that the electric connections in the seabed must be solid structures built by bacteria," says PhD student Christian Pfeffer, Aarhus University.

He could interrupt the electric currents by pulling a thin wire horizontally through the seafloor. Just as when an excavator cuts our electric cables.

In microscopes, scientists found a hitherto unknown type of long, multi-cellular bacteria that was always present when scientists measured the electric currents.

"The incredible idea that these bacteria should be electric cables really fell into place when, inside the bacteria, we saw wire-like strings enclosed by a membrane," says Nils Risgaard-Petersen, Aarhus University. Kilometers of living cables

The bacterium is one hundred times thinner than a hair and the whole bacterium functions as an electric cable with a number of insulated wires within it. Quite similar to the electric cables we know from our daily lives.

"Such unique insulated biological wires seem simple but with incredible complexity at nanoscale," says PhD student Jie Song, Aarhus University, who used nanotools to map the electrical properties of the cable bacteria.