As the world's temperatures get warmer, it's getting harder and harder for some of our most advanced telescopes to make observations.
When designing high-tech equipment, particularly with the precision needed to see into space, temperature becomes a big concern. Thermal properties of the environment around telescopes can cause impact how it behaves optically and image blurring might be on the table. Simply put, some telescopes just weren't designed to handle changes caused by the higher temperatures of current world.
A recently published study details some of the impacts of climate change on astronomical observation. Specifically, the research focuses on decades worth of observations and studies from the European Southern Observatory's Very Large Telescope (VLT). I like to imagine that the naming of this telescope went a little something like this:
Lead astronomer: "What should we name it"
Astronomer 1: "Well, it is large... one might say, very large."
Astronomer 2: "Oh, and it's a telescope!"
Astronomer 1: "Perfect, we shall call it the Very Large Telescope!"
Lead Astronomer: "Good job team, now let's go grab lunch."
Science humor aside, the VLT is of the utmost importance when it comes to astronomical observation – it's the world's "most advanced visible-light astronomical observatory."
Data from the observatory revealed some of the ways in which climate change is affecting its ability to see into space. According to Faustine Cantalloube, lead researcher on the study "Climate change is affecting and will increasingly affect astronomical observations, particularly in terms of dome seeing, surface-layer turbulence, atmospheric water vapor content, and the wind-driven halo effect in exoplanet direct imaging."
Located in the Atacama desert in Chile, this specific region has warmed on average by 2.7 degrees Fahrenheit (1.5 degrees Celsius) over the last 40 years. This outpaces warming trends in the rest of the world over the same relative period, which stands at around 1.7 degrees Fahrenheit (1 degree Celsius).
The VLT sits in the Atacama desert, the driest place on Earth outside of the Antarctic. So it's no surprise that it outpaces average global warming rate. It being in the driest place is no coincidence. Although, even the low humidity in the Atacama cannot compensate for the issues caused by the higher temperatures in the region.
The effects of temperature on the VLT
Most notably, if the temperature at the end of the day is higher than 60 degrees Fahrenheit (16 degrees Celsius), the cooling system on the VLT can malfunction. When it was first installed in 1991, this wasn't an issue, but the climate has warmed so rapidly that it's becoming a recurring issue throughout the year.
The higher temperature can lead to a loss of image resolution in the telescope, due to the temperatures differential between the area outside the dome of the telescope and inside the dome. This causes an issue known as 'Dome Seeing', which Dr. Cantalloube explains as the degradation in the image quality due to turbulence in the air within the dome caused by a thermal differential between the inside and outside of the dome.
Increases in ambient temperatures in the region also makes the atmosphere less clear, which also leads to blurriness, and decreases how far the telescope can see.
Extreme weather events
Extreme weather events, particularly increased precipitation and cloud movements, can also have a negative impact. As the global climate warms, this brings changes to the movement of the jet stream and to other weather patterns. In reference to the Atacama and the VLT's direct location, it's expected that increased thermal changes in the region will bring increased atmospheric turbulence, along with higher humidity. These effects are detailed closely in the study, with the researchers noting:
"On the monthly average, we can directly see the seasonal changes (being more prominent in winter) and on the yearly average, we see longer trends linked with the El Niño Southern Oscillation (ENSO, 2 to 7 years variation) and the Pacific Decadal Oscillation (PDO, on longer time scales), both linked to the sea surface temperature anomalies. Over the 40 years of ERA5 data, we observe a slight increase in the average wind speed by about 3–4 m/s. When relating to the Niño 3.4 index (the best proxy for the strength of the ENSO), we observe a large fraction of wind-driven halo during strong El Niño events (the warm phase of the ENSO), such as the one in 2015."
It should also be noted that the main goal of this study was to examine historical data and how it related to the problems that the telescope is currently facing.
By looking back at several decades worth of data on the VLT and the surrounding climate, the researchers are able to predict the detrimental effects that further climate change may have on the telescopes' ability to see clearly into outer space.
The recommendation of the researchers
The biggest recommendation was one of planning for future telescopic construction. They suggest that future telescopes need to be designed to accommodate more extreme weather events, as there's a strong potential that the changes which have affected the VLT will become more prevalent and will affect other areas as well.
Their message at the end of the paper stating we need to follow through with sustainable actions against climate crises via
- Communicating inside and outside our community about the impact of climate change on our planet and our society,
- Optimizing the energy resources expended for our professional activity, and
- Revisiting and reshaping the whole scheme of research in astronomy to decrease our global footprint.
But of course, "To do so, a massive cultural shift is needed, and it is of prime importance that astronomy uses its unique perspective to claim this simple fact: there is no planet B."
Regardless of the cause, finding a way to mitigate this problem is paramount to our ability to conduct scientific research involving telescopes.