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How Global Warming Affects Astronomical Observations

The VLT’s Laser Guide Star: A laser beam launched from VLT’s 8.2-metre Yepun telescope traverses the majestic southern sky, creating an artificial star 90 km in the Earth’s high mesosphere. The Laser Guide Star (LGS) is part of the VLT’s Adaptive Optics system and is used as a reference to correct images for the blurring effect of the atmosphere. Credit: ESO/G. Hüdepohl (atacamaphoto.com)

The quality of astronomical observations from the ground closely depends on the brightness of the atmosphere above the location from which they were taken. Locations for telescopes are therefore very carefully selected. They are often high above sea level, so there is less atmosphere between them and their targets. Many telescopes have also been built in deserts, as clouds and even water vapor hinder a clear view of the night sky.

A team of researchers led by the University of Bern and the National Center of Competence in Research (NCCR) PlanetS shows in a study published in the journal Astronomy and Astrophysics and presented at the Europlanet Science Congress 2022 in Granada, how one of the greatest challenges of our time – anthropogenic climate change – is now even affecting our view of the cosmos.

A blind spot in the selection process

“Even though telescopes usually have a lifetime of decades, site selection only considers atmospheric conditions over a short period of time. Usually in the past five years – too short to capture long-term trends, let alone future ones. changes due to global warming,” Caroline Haslebacher, lead author of the study and researcher at the NCCR PlanetS at the University of Bern, points out.

The team of researchers from the University of Bern and the NCCR PlanetS, ETH Zurich, the European Southern Observatory (ESO) and the University of Reading in the UK therefore took on the task of showing the long-term perspective.

Deteriorating conditions around the world

Their analysis of future climate trends, based on high-resolution global climate models, shows that major astronomical observatories from Hawaii to the Canary Islands, Chile, Mexico, South Africa and Australia are likely to experience a rise in temperature and atmospheric water content by 2050. . , can in turn mean a loss of observation time, as well as a loss of quality in the observations.

“Today, astronomical observatories are designed to operate under current on-site conditions and have few options for adaptation. Potential impacts of climatic conditions on telescopes are therefore a higher risk of condensation from an elevated dew point or faulty cooling systems. , which can lead to more air turbulence in the telescope dome,” Haslebacher said.

The fact that the effects of climate change on observatories had not been taken into account before was not a mistake, as study co-author Marie-Estelle Demory says, but more because of model limitations. “This is the first time such a study is possible. The higher resolution of the global climate models developed through the Horizon 2020 PRIMAVERA project allowed us to examine conditions in different locations around the world with great fidelity – something that we couldn’t with conventional models. These models are valuable tools for the work we do at the Wyss Academy,” said the senior scientist at the University of Bern and member of the Wyss Academy for Nature.

“As a result, we can now say with certainty that anthropogenic climate change must be taken into account in the selection of sites for next-generation telescopes and in the construction and maintenance of astronomical facilities,” says Haslebacher.

Long-term liquid water also on non-terrestrial planets?

More information:
C. Haslebacher et al., Impact of climate change on site features of eight major astronomical observatories using high-resolution global climate projections to 2050. Expected rise in temperature and humidity leads to worse astronomical observation conditions, Astronomy and Astrophysics (2022). DOI: 10.1051/0004-6361/202142493

Quote: How Global Warming Affects Astronomical Observations (2022, Sept. 22) retrieved Sept. 22, 2022 from https://phys.org/news/2022-09-global-affects-astronomical.html

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