VOA常速英语:Scientists Looking at Coldest Objects in Universe

Astronomers have a new powerful tool for looking deep into space while trying to better understand the origins of the universe.  It is a new telescope that will look for signals coming from the coldest objects in deep space. The telescope is called Atacama Large Millimeter/sub-millimeter Array or "ALMA.  The last of its 66-dish antennas has been moved to its site in Chile's high desert

Under an almost always cloudless sky, in Chile's cold and barren Atacama desert, 5,000 meters above sea level and away from any electromagnetic interference, ALMA’s dish antennas listen to signals coming from distant cold objects.

Even the coldest matter in space, such as dust and gas, emit signals between infrared light and radio waves, with wavelengths smaller than a millimeter.  Catching them requires either a dish antenna of enormous proportions, or an array of smaller ones, with a supercomputer to consolidate the data.

The equipment that receives those signals must be kept at even colder temperatures, says astronomer Gianni Marconi.

“You have to amplify the signal that is really really low in conditions that are really really extreme, so this is the reason because of our detectors are kept at the minimum temperature possible," he said. "We are few degree above the zero absolute.”

Signals from ALMA’s 66 antennas are processed in a supercomputer called Correlator. Electronic engineer Lorenzo Martinez says each of its four parts can process a lot of data.

“We have 120 gigabytes per second that is produced in each antenna," he said. "Well, if you do the math, these are astronomical numbers.”

It is tricky to combine the signals from several dish antennas.  Scientists have to periodically rearrange them in order to find the best configuration with the least amount of radio interference.

Juan Carlos Salamanca operates a special multi-wheeled transporter called ‘Lore’ to move the antennas across the flat desert floor.

“One antenna weighs almost 100 tons and you need to transport it to 5,000 meters and the truck needs to have the capability to work without a problem at 5,000 meters,” he said.

Marconi says the ALMA telescope will open a new window on the most distant early formed galaxies.

“This is what ALMA is doing, [giving us a new] Horizon looking at the beginning of the universe, at the beginning of the star formation, at the beginning of the formation of our cosmic structure,” he said.

ALMA is a joint project funded by Europe, United States, Canada, East Asia and Chile.