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Scientists point to the best place on Earth to see the cosmos at night



Aurora and stars, as seen from the US Amundsen-Scott South Pole Station in July 2020

Aurora and stars, as seen from the US Amundsen-Scott South Pole Station in July 2020

Geoff Chen

If you want to get the best possible view of the stars from here on Earth, you need to prepare for a long journey to the coldest place on the planet. About 650 nautical miles from the eastern edge of Antarctica you will find yourself on a pristine white plate, drawing to the horizon: Dome A.

A new study by Chinese researchers at the Dome A research station, published in the journal Nature on Wednesday, suggests it may be the best place on Earth for astronomers to survey the skies. . But you have to get there first.

The trek to Dome A is intense.

First, you got to Antarctica. It’s not hard these days, but you have to take an icebreaker so you can drop it on the shore of the East Antarctic. A helicopter takes you from the ship on the icy continent, and then the real journey begins. From there, you have to make your way through the ice in a container-like vehicle, pulled by a tractor at about 6 miles (10 kilometers) per hour. It takes about two weeks to arrive at your destination.

Only then can you begin to set up your telescope on an eight-meter high platform in the middle of the snow desert.

This is exactly what the team of researchers did during the summer of 2018-19 – and they report that the weather conditions are so good their views of the night sky are different from those anywhere else on Earth.

“The experience was unique and exciting,” says Zhaohui Shang, one of the researchers who was part of the expedition and co-authored the study. “We had a lot of hard work to complete, just about 3 weeks in the summer at Dome A.”

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The location of dome A.

Google Maps

Immaculate Conception

A dome has long been considered a great place for the look of the stars. But what makes the coldest place on Earth particularly good for seeing the cosmos?

“It comes down to atmospheric turbulence,” explains Michael Ashley, an astrophysicist at the University of New South Wales and co-author of the study.

“If you go to a good dark place somewhere, you see the stars being thrown and the twinkling is bad.”

Ashley says that planting is caused by the Earth’s atmosphere and is not helpful to astronomers trying to imagine the cosmos. But in Antarctica, there is little turbulence, because it is so flat and the winds moving around the area are extremely light.

“If you just have winds to spend on a snow surface with a dead cut, there’s no chance of generating turbulence,” he explains.

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Ice to see: the telescope was set up in dome A.

In addition, water vapor can wreak havoc with astronomy because it absorbs light, particularly at infrared wavelengths. But Antarctica is very dry – the water freezes – and that’s a big advantage for those looking to study the sky. Particularly if you want to study the cosmos at a millimeter wavelength, as does the Atacama range in the Chilean desert.

“We took a terahertz telescope there and found spectacular data,” says Ashley.

“And we’re much better than Atacama in terms of site conditions.”

Observations from telescopes at dome A are about two and a half times better than what you can see at some of the best Earth-based observatories in Chile or Hawaii.

China is planning to build another infrared optical telescope at the site known as the Kunlun Dark Universe Survey Telescope, KDUST. It has been in the works for about a decade and you see China put a telescope, almost twice as big, in place.

“At the moment, it’s kind of a stoppage in a review,” Ashley says. “I think they’re looking at it very closely. And I think this Nature card should go pretty far in some way to give it a bit of a boost.”

China’s recent scientific efforts also extend beyond the Earth, as well. Last week, the country launched the Tianwen-1 mission. A spaceship, carrying three robotic explorers, is located on the way to Mars and is expected to arrive there in February 2021.


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