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Our view of space is becoming blurrier as our planet warms, astronomers warn



The world’s most advanced telescopes have not been made for today’s temperatures and are interfering with our observations of the night sky.

Thirty-year data from the Paranal Observatory in northern Chile, home of the European Southern Observatory’s Very Large Telescope (VLT), revealed several ways in which climate change is already affecting astronomical observations. And several ways it could get worse.

The VLT is located in the Atacama Desert, the driest place on Earth outside of Antarctica.

While the rest of the world has warmed by an average of 1 ° C since the pre-industrial era, the Atacama has warmed by 1.5 ° C over the past four decades.

The VLT simply wasn̵

7;t designed for such hot conditions. First, its cooling system does not work properly if the sunset temperature is above 16 ° C. Yet over the years there have been more occasions when end-of-day temperatures have exceeded this threshold.

This means that when the dome opens, the outside temperature is warmer than the inside dome and this can lead to a reduction in image resolution due to internal turbulence, something astronomers refer to as “dome vision”.

Essentially, this temperature causes turbulence inside the dome, which degrades image quality and causes blurring.

Outside of the dome, climate change is also affecting turbulence in the atmosphere, and the authors of this new study noted an increase in turbulence in the air near the ground, which also caused more blurring in the images.

Given recent construction changes in the landscape, the team cannot directly link this change to global warming, but they speak of a broader potential threat as our planet warms rapidly.

Numerous state-of-the-art instruments are also installed at the telescope, sensitive to local atmospheric changes.

Even though the Atacama is a desert, this region is still closely linked to El Niño events and the summer monsoons, both of which are expected to intensify due to future climate change. But to make infrared observations of the night sky, it is necessary that there is a low water vapor content in the air.

The southern subtropical jet stream, which in turn is influenced by El Niño, is also responsible for causing a ‘wind-driven halo’, where atmospheric turbulence conditions vary so rapidly that the telescope’s control system cannot correct them.

“This limits the contrast capabilities of the instrument and could potentially limit studies on exoplanets,” explain the authors.

“An increase in water vapor in the atmosphere could also lead to a reduction in the astronomical signal.”

Relative humidity and cloud cover can also interfere with submillimeter and radio wavelength observations, and although the data suggests the Atacama will become drier in the future, we still need much more research on local and global climate. and on all its various complexities before we can say for sure.

If the world warms up another 4 ° C before the turn of the century – a worst case scenario – the team of astronomers, climatologists and meteorologists say our images of the night sky will likely only get blurrier.

That’s why we should build future telescopes with extreme warming scenarios in mind, they say, because otherwise our technology won’t do well.

“Each telescope site is likely to have its own microclimate that requires individual study,” admits the team, “but we highlighted three different areas – dome vision, surface layer turbulence, and wind-driven halo effect – that will have an effect. growing negative impact on astronomical observations at Paranal as climate change worsens. ”

And the authors also have another message. Their article joins six other articles in the current issue of Nature Astronomy, dedicated to raising awareness about climate change and how it affects our vision of space.

Although astronomy is not often linked to climate change, planetary scientists and astrobiologists can offer unique perspectives to research on our planet.

In the past, astronomers have expressed concern about geoengineering solutions, which they fear could brighten or blur the night sky and make sharp astronomical observations much more challenging.

“[A]Stronomists know that the origin of life on Earth was a complex process made possible only by the coincidence of extremely rare circumstances, “explains the study’s press release.

“There is no second Earth in our neighborhood.”

The study was published in Nature Astronomy.


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