SANTA CRUZ DE TENERIFE, June 21 (EUROPA PRESS) –
The director of the Starlight Foundation and researcher at the Instituto de Astrofísica de Canarias (IAC), Antonia M. Varela, has written the article entitled ‘The growing effects of light pollution on professional and amateur astronomy’, recently published in the magazine ‘ Science’, in which he analyzes how it is increasingly difficult to observe the night sky due to artificial night light, radio interference and the rapid increase in satellite constellations
Each of these factors has an adverse impact on astronomical observations, limiting scientific discoveries, cultural connections to the night sky, and astrotourism opportunities.
“Until just a couple of years ago, our main concern was focused on the progressive loss of the night sky due to the increasing increase in light pollution,” explains Varela. “We astronomers were the first to warn of this threat and point out that this deterioration had serious implications not only for science, but also for the environment, biodiversity, health, associated cultural heritage and sustainable socio-economic development through of astrotourism”, he adds.
83% of the world’s population lives under light-polluted skies and 23% of the world’s land surface between 75ºN and 60ºS is already light-polluted, growing by 2% per year. In other words, if everything continues as before, it will double in about 35 years. By 2050, the world population is expected to reach 9.6 billion people, of whom 68% are expected to live in urban areas.
Astronomical observatories, located precisely in remote parts of the planet due to their very dark skies, are being seriously threatened by increasing light pollution. Ground-based astronomical observations continue to drive important discoveries with far-reaching implications in astrophysics and fundamental physics. They are often essential for interpreting observations from space telescopes. There are more than 40 ground-based optical telescopes with mirrors 3 meters or more in diameter. Astronomical observations require dark skies. Any glare from the sky can saturate the weak signal from astronomical objects, making them impossible to detect.
However, Varela also warns that in recent years there has been a rise in new and very serious threats to professional and amateur astronomy. The deployment of satellites in Low Earth Orbit (LEO) has had an unforeseen impact on astronomy. When a prototype batch of 60 satellites was launched in May 2019, astronomers were surprised by how bright they appeared from the ground.
With plans for up to 400,000 satellites in such constellations by 2030, thousands of these satellites will be visible from every location at any given time. This means that up to 30% of wide field exposures in a large telescope would be lost during the early hours of the night and almost 50% of twilight exposures would be contaminated. Some of the projects that will be seriously affected will be automated surveys in search of moving objects such as potentially dangerous asteroids.
But constellations of low-orbiting satellites will not only affect nighttime observations, they will also have consequences for radio astronomy, which observes the Universe at wavelengths that are also used by human-generated radio communications. And it is that the increase in bandwidth and transmission power of radio communications has caused an increase in radio frequency interference in astronomical observations. The array of LEO constellations will produce hundreds of bright, fast-moving sources of radio interference, visible to radio telescopes at any time of day.
Light pollution already has effective regulations and technology for its reduction and some steps are already being taken, the first of which was the 1988 Sky Law of the Canary Islands, but the risk of losing the night sky due to mega-constellations is advancing very rapidly. it is devastating and the solutions are complex. The proliferation of small satellites increases the risk of collision and, therefore, the risk of generating space debris. These collisions can endanger observation satellites, terrestrial surveillance and communications, crucial for our security among other aspects.
CONSEQUENCES FOR AMATEUR ASTRONOMY
Approximately one million people are engaged in amateur astronomy, two orders of magnitude more than the number of professional astronomers worldwide. Amateur astronomy is also strongly threatened by artificial light at night (ALAN) and by mega-constellations of satellites, especially in the realms of amateur-professional science research programs, astrophotography and astrotourism.
Amateur astronomers use cameras and telescopes with wider fields of view than large professional telescopes, so their images are more likely to contain artificial satellite trails.
Amateur astronomers discover comets, search for supernovae, conduct variable star and meteorite tracking campaigns, and confirm exoplanet candidates. These activities are especially vulnerable to light pollution and mega-constellations of satellites because amateur astronomers do not have access to the economic and technological resources necessary to mitigate its effects. The increasing levels of light pollution seriously compromise these activities, which will be practically impossible in the next decade if current trends continue.
“It is absolutely necessary that observatories, industry, the astronomical community, science funding bodies, national and international policy makers work in a coordinated manner seeking the necessary measures to limit the impact of light pollution, radio frequencies and mega-constellations on astronomy”, insists the researcher.
In his article, Varela points out the need to establish strict national and international regulations and standards and monitor their compliance. In this sense, the role played by the recently created Center for the Protection of the Dark and Silent Sky (CPS) from interference from mega-constellations of the IAU is encouraging.
“It is urgent to establish a global pact in defense of the sky – concludes the director of the Starlight Foundation -. This implies educating and raising awareness in society as a whole, something that we do at the Starlight Foundation, through the dissemination of astronomy and the local socio-economic development of local communities through astrotourism, adding adhesions to the Declaration of La Palma in Defense of the Night Sky and the Right to the Light of the Stars, and going one step further, defending before the United Nations together with the association of business women and professionals BPW Spain, that the sky is a Sustainable Development Goal, because without sky there is no planet”.
