Away from the glare of the blinding lights of civilization, an unobstructed view of the night sky makes you feel as if you are standing on the edge of eternity. But there is a place on Earth where the views extend a little more than anywhere else.
The researchers have measured the clarity of the stars at a major research station in Antarctica, discovering that it exceeds today’s top points for astronomy. The result may not be surprising, but for most of us, it’s a bit of a disappointment.
Dome A is the highest ice dome on the Antarctic polar plateau. Rising more than 4 kilometers (more than 13,000 feet) from sea level, and sitting approximately 1,200 kilometers (750 miles) from the ocean in the middle of the coldest continent, it is likely to cool.
In fact, temperatures can drop to -90 degrees Celsius (-130 Fahrenheit).
However, if that doesn’t discourage you, the rewards might be worth it.
This icy peak provides an astronomical perspective like no other, with a relatively unbroken view of light pollution spots, interference from numerous passing satellites, or even the occasional passing cloud.
“A telescope located in Dome A could outperform a similar telescope located anywhere else on the planet,” says Paul Hickson, an astronomer at the University of British Columbia (UBC).
“The combination of high altitude, low temperature, long periods of continuous darkness and an exceptionally stable atmosphere make Dome A a very attractive location for optical and infrared astronomy. A telescope located there would have sharper images and could detect fainter objects.” .
If you really wanted to get a deeper look at the depths of space and time, you would need to escape from the closest part of the atmosphere called the boundary layer. The gases that make up this thin blanket are not only clogged by dust and moisture: the heat from the ground makes it shine, making the stars seem to shine.
One way to quantify this annoying flickering is through a figure called astronomical vision, which is a description of the apparent diameter of a light source in units called arc seconds.
This number means the difference of distinguishing a point of light as a source or multiple, so the lower the turbulence and the clearer vision, the smaller the object will be (and therefore, the shorter the second of the arc ).
Right now, the best ground-based telescopes available to astronomers are at elevations where the boundary layer is relatively thin.
Chile’s high Atacama desert is currently considered one of the best places for telescopes, home to the Atacama Large Millimeter Array for radio imaging, and will soon house the incredibly huge Giant Magellan Telescope, a beast that will surpass Hubble.
In this corner of the world, atmospheric conditions can provide astronomical vision at regular figures as low as around 0.66 arcseconds. On some clear nights, that number could even cut in half for a few hours here and there.
Hickson and colleagues measured astronomical vision at Dome A’s Kunlun Station, a Chinese research post that was already considered an attractive site for astronomers.
Another cold inland Antarctic site called Dome C already had estimated values of 0.23 to 0.36 arcseconds. But no one yet had a good measure with respect to those in Dome A.
Setting his measuring equipment to 8 meters from the ground, the team recorded numbers as low as 0.13 arcseconds, placing him in the stadium of the observatories out of the atmosphere. In fact, the number reflects a boundary layer only 14 meters thick.
“After a decade of indirect evidence and theoretical reasoning, we finally have direct observation evidence of the extraordinarily good conditions at Dome A,” says astronomer Michael Ashley of the University of New South Wales in Australia.
Before packing your shaggy and trusty old telescope for a night of stargazing, you should know that conditions at Dome A don’t just threaten freezing. Your equipment would need to be state of the art.
“Our telescope observed the sky fully automatically at an unmanned station in Antarctica for seven months, with the air temperature dropping to -75 degrees Celsius at times. In itself, that’s a technological advance,” says the author. study lead UBC astronomer Bin Ma.
Even with advanced technology that could operate from a warmer location, the team had to deal with the scourge of ice. Overcoming the hurdle of extreme temperatures could help see even further, by as much as 12 percent.
While most of your reading of this will never see the clear sky observing conditions of Dome A, we can all benefit from the universal ideas of major astronomy projects set up there in the future.
This research was published in Nature.
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