Astronomers find coldest, driest, calmest place on Earth

August 31, 2009

The search for the best observatory site in the world has lead to the discovery of what is thought to be the coldest, driest, calmest place on Earth. No human is thought to have ever been there but it is expected to yield images of the heavens three times sharper than any ever taken from the ground.

The joint US-Australian research team combined data from satellites, ground stations and climate models in a study to assess the many factors that affect astronomy - cloud cover, temperature, sky-brightness, water vapour, wind speeds and atmospheric turbulence.

The researchers pinpointed a site, known simply as Ridge A, that is 4,053m high up on the Antarctic Plateau. It is not only particularly remote but extremely cold and dry. The study revealed that Ridge A has an average winter temperature of minus 70C and that the content of the entire atmosphere there is sometimes less than the thickness of a human hair.

It is also extremely calm, which means that there is very little of the atmospheric turbulence elsewhere that makes stars appear to twinkle: "It's so calm that there's almost no wind or weather there at all," says Dr Will Saunders, of the Anglo-Australian and visiting professor to UNSW, who led the study.

"The astronomical images taken at Ridge A should be at least three times sharper than at the best sites currently used by astronomers," says Dr Saunders. "Because the sky there is so much darker and drier, it means that a modestly-sized telescope there would be as powerful as the largest telescopes anywhere else on earth."

They found that the best place in almost all respects was not the highest point on the Plateau - called Dome A - but 150km away along a flat ridge.

"Ridge A looks to be significantly better than elsewhere on the Antarctic plateau and far superior to the best existing observatories on high mountain tops in Hawaii and Chile," says Dr Saunders.

The finding is published today in the Publications of the Astronomical Society. Located within the Australian Antarctic Territory (81.5◦ S 73.5◦ E), the site is 144km from an international robotic observatory and the proposed new Chinese 'Kunlun' base at Dome A (80.37 S 77.53 E).

Interest in Antarctica as a site for astronomical and space observatories has accelerated since 2004 when UNSW astronomers published a paper in the journal Nature confirming that a ground-based telescope at Dome C, another Antarctic plateau site, could take images nearly as good as those from the space-based Hubble telescope.

Last year, the Anglo-Australian Observatory completed the first detailed study into the formidable practical problems of building and running the proposed optical/infra-red PILOT telescope project in Antarctica. The 2.5-metre telescope will cost over AUD$10million and is planned for construction at the French/Italian Concordia Station at Dome C by 2012.

"Australia contains no world-class astronomical sites, and Australian astronomers face a choice between being minor players in telescopes in Chile or joining Chinese or European efforts to build the first major Antarctic observatory," says Dr Saunders.

Source: University of New South Wales (news : web)

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2.6 / 5 (5) Aug 31, 2009
pictures as clear as Hubble --- more power to you But I wonder what the comparison is to the Hubble replacement
4.8 / 5 (5) Aug 31, 2009
I'd like to think of it as practice for building a scope on the moon. Sure it's not the same but no doubt some of the lessons will carry over.
5 / 5 (3) Aug 31, 2009
darpa is building multiple high altitude blimps for long duration (months) missions at 70,000 feet. . once the designs exist. building any one of them, and fitting it with a teloscope should be a HELL of a lot cheaper than building a ground based telescope in the most remote grounded location on earth.

i'd be surpirsed if , at any location in the world at an altitude of 70,000 feet, you didnt' get a picture at least as good as that from the ground in antarctica.
2.4 / 5 (5) Aug 31, 2009
the blimps is the way to go. You can have dozens or hundreds of smaller mirrors that combined will surpass anything in space or on the moon simply do their operational size from combining many smaller mirrors to act a one much larger than can physically be made anywhere.
4 / 5 (8) Aug 31, 2009
The blimps move too much. Put an automated telescope on ridge A that's as big or bigger as the biggest scopes and it will see three times further.
1.7 / 5 (14) Aug 31, 2009
Actually, having worked on a major high-profile astronomy project? "No way" is the way to go. Astronomy is a science that benefits 99.999% of the population by no greater extent than to provide pretty pictures. It's no threat to humanity (unlike nuclear physics), but at this stage, it's also no use. 100 years from now, maybe. 200 years, when we can get to the nearest stars, absolutely. By that time technology will be so advanced, kids with cameras will be able to make discoveries. In the meanwhile, NASA-type probes to bodies in the solar system are enough to chew on. Forget the pretty pictures of distant galaxies. So what.
5 / 5 (4) Aug 31, 2009
It would also be the perfect place for simulating a Mars colony. At -70 C, the temperature wouldn't be much different!
4.9 / 5 (48) Aug 31, 2009
I'm sure both methods will be pursued.
4.2 / 5 (6) Aug 31, 2009
docknowledge - by all means let's just not bother with it at all. I'm sure when we're ready for distant space travel it will all just come to us so we won't need to have laid down any ground work. Let's not do what we can with the time we all have to discover and document what we can. Pursuit of knowledge? Nah - let's wait for it pursue us.
5 / 5 (2) Aug 31, 2009
OMG I so want to go to this place and have a drink. It would be so calm and relaxing.

I'll have to remember to bring my warm jacket though.
4.8 / 5 (4) Sep 01, 2009
docknowledge. There are plenty of important discoveries that can be made with big telescopes. How about finding Earth sized planets with a signature of life? That would have profound psychological implications on people.

And what about testing superstring theories? If those are proven with smart observations it would greatly advance physics and might yield practical applications.

Then there's also the need to scan for comets and asteroids which could endanger the Earth.
3 / 5 (1) Sep 01, 2009
It will need a dedicated satellite to guarantee continuous and abundant communications. Not sure if a polar geostationary satellite is feasible due to the need for continuous repositioning, (no orbit). Ion drive would provide a possible answer, but it will increase the costs of satellite (build and maintenance) and the establishment the observation platform. What are the options for cabled solutions to Australia or South America? Almost zero, I guess.

Seems a great pity that this location was not researched before all the investment in Chile.

As for the floating platform, the atmospheric disturbance reduction would be significantly undermined by platform movement which can not be completely eliminated even with the fast reacting stabilizers. Cheap solutions are seldom best solutions. However, I am sure that if the telescope is pointing down it would provide a very financially attractive alternative to satellite based terrestrial surveying, especially while America has no operational space launch vehicles.
4 / 5 (1) Sep 01, 2009
For the polar satellite, we could try one of Robert Forward's "statites". They were designed to use a small solar sail to counteract Earth's gravity, and could hover directly over the pole. The physics aren't in doubt, but whether we could build one that would stay in place may be. It would be an interesting, and possibly useful, experiment, considering that we already have year-round bases in Antarctica that would be able to use it.

One advantage of Chile is that more of the northern sky is visible. A polar observatory is basically limited to the stars of one hemisphere.
4.5 / 5 (2) Sep 01, 2009
sounds like a peaceful place without humans. perhaps we could drop a robotic rover with a moderately sized telescope there just as a trial.....easy to do, just fly it in and let it fall to the ground with a parachute, you could use a scaled up larger size updated version of the mars exploring robots except they coudl run off both solar and wind energy. presumably the robots wouldn't move much either so they would only need enough power to move the angle of the telescope/run electronics and transmit data via sattelite.

if the test trial yield positive results cheaply, consider the full scale project.
4 / 5 (1) Sep 02, 2009
Not a bad idea, and a good way to test rover technology.
1 / 5 (1) Sep 06, 2009
but it's a dry cold
1 / 5 (1) Sep 06, 2009
By the time they get this built AGW will have washed Antarctica away and the telescope will be at sea level, higher than now, but not high enough. 8^)
5 / 5 (2) Sep 06, 2009
Build the biggest damn telescope you can! If that thing is almost equivalent to being in space, it's like gaining the ability to make a satelite with no weight restriction and no launch costs! build it!! And if you need help, call me!!!
not rated yet Sep 07, 2009
@ nkalanaga, Even though telescopes in Chile (or other Southern Hemisphere observatories) may be able to image more northerly declinations, think of the long integration times possible during the long Austral Winters. Imagine weeks (or months) of CCD integrations of the Magellanic Clouds, the Andromeda Galaxy, Sgr-A* or some distant Lyman-alpha emitter. A large telescope at this location would be ideal for imaging VERY FAINT objects, especially at near-IR wavelengths, useful for imaging distant (z>6) objects.

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