Ultima Thule

In ancient times the northernmost region of the habitable world - hence, any distant, unknown or mysterious land.

Monday, August 07, 2006

In search of the big bang: a cosmic event

By Aussiegirl

The description, from the article, of this magnificent device says it all: Atacama Large Millimetre Array (Alma), the name given to the network of telescope dishes that will open a new window on to the early universe.[....] By 2012, the plateau will be home to an astronomical "time machine" able to look as far back as the cosmic events that followed the Big Bang.

Independent Online Edition > Science & Technology

In search of the big bang: a cosmic event

High up in the Chilean Andes, more than 5,000 metres above sea level, astronomers are building a telescopic "time machine" that promises to offer a glimpse of the moment the universe was created 13 billion years ago.

Steve Connor reports from Chajnantor
Published: 07 August 2006

A short walk in the vast, dry plateau of Chajnantor in the high Andes of Chile is an arduous and light-headed experience. Here the air is so thin that day trippers have to carry oxygen canisters to avoid the debilitating symptoms of altitude sickness.

Chajnantor does not invite strenuous activity and yet this is the site of the most ambitious high-altitude construction project in the world. By 2012, the plateau will be home to an astronomical "time machine" able to look as far back as the cosmic events that followed the Big Bang.

A huge international project is under way at Chajnantor to build a $1bn telescope made up of 64 individual dishes or antennas, each of which will be the size of a two-storey suburban house.

The array will act in unison to peer through the dense dust clouds of deep space, so permitting astronomers to gather ancient relic radiation from the earliest stars and galaxies that formed some 13 billion years ago.

"It should be able to see all the way back to when the first galaxies were formed after the Big Bang, basically as far as it is possible to see," said John Richer, a Cambridge University astronomer who represents Britain's interests in the telescope. [....]

Each of Alma's 64 antennas, which measure 12 metres across, will be positioned in an array that will cover a distance of 14 kilometres (10 miles) at its widest point on the Chajnantor plateau.

Alma is designed to capture radiation that is in the millimetre-wave band of the electromagnetic spectrum. Unlike optical light, this radiation can penetrate matter such as interstellar dust clouds, which block light at optical wavelengths.

Millimetre wave radiation can pass through something as thick as a telephone directory, which is why Alma will be able to see roughly twice as many stars and galaxies as the Hubble Space Telescope. When Alma is finished in 2012, it will be the highest terrestrial telescope and the biggest and most expensive millimetre-wave telescope on the planet. [....]

But the real excitement over Alma comes from the astronomers who get to play with an instrument from their dreams - one that will let them analyse objects they have yet to discover.

Dr Richer said that, in addition to seeing through dust clouds, millimetre-wave astronomy was finely tuned to study "cool" objects, the many stars and galaxies that do not emit the sort of radiation picked up by ordinary optical telescopes.

"Every time we observe a new piece of sky with Alma, every three minutes, we will detect new galaxies that have never been seen before - just wherever you point the telescope you will see new galaxies," Dr Richer said.

"Here we're trying to open a really new view on the universe with this magical wavelength of one millimetre and below. Alma's going to be the first major telescope that allows us to capture high quality images at these wavelengths," he said. [....]


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