The sky is running out of stars: "There are children who have not seen the Milky Way in their lives"

On March 30, 1973, the scientist Kurt W. Riegel warned in the magazine

about how light pollution was becoming a threat to astronomy: "It is damaging some astronomical programs and it is likely to become an important factor that limit progress in the next decade. It is very difficult to find suitable sites in the US for new dark sky observation facilities," said the Johns Hopkins University astronomer.

Half a century later, his predictions have not only come true.

Another study published today in the same magazine shows that despite the measures put in place and the greater awareness of

.

There are many places on Earth where it never gets completely dark, and forecasts suggest that for years to come, artificial light will continue to outshine the stars at a higher rate than satellite observations suggested.

Because it will be increasingly difficult to see stars.

To put into perspective what this increase in artificial lighting means, the authors of this study offer this estimate based on their data: a person born now in a place where 250 stars are visible will only be able to see 100 in 18 years. because of light pollution.

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The new research, led by

has been carried out with observations made by 51,351 citizen scientists over the last 12 years, between 2011 and 2022, around the world.

Until now, estimates of the impact of artificial light were made mostly with satellites and it was estimated that artificial light emissions increased by 2% per year.

But those satellites that can measure the brightness of the global sky have limited resolution and sensitivity, and often cannot observe the wavelengths produced by modern LED lights that have proliferated so widely in the past decade.

Using observations from the ground, they have now calculated that

Photos taken by astronauts of the same area of ​​Southeast Calgary, Alberta (Canada) in 2010 (top) and 2021 (bottom) Johnson Space Center / NASA

"The results presented in this study are extremely worrying, and not only for astronomers, since they affect all of humanity. We are terrified to think that this runaway light pollution could mean, in the not too distant future, the end of dark nights and the end of ground-based astronomy," Rafael Bachiller, director of the National Astronomical Observatory (IGN), told this newspaper.

"A nightmare for astronomers"

As the Spanish scientist explains, without any connection to this

"the bright background of the sky is a true nightmare for astronomers" which is forcing them to move the observatories to the most remote places on the planet." And to this is added another more recent problem, which is the

which pose a problem even in the most remote astronomical observatories on Earth".

And it is that from his point of view, "the situation is alarming.

. The Milky Way is hidden for a third of humanity, which includes to more than 60% of Europeans. If we look at the images taken from the International Space Station (ISS), the Earth at night increasingly resembles a huge light bulb that shines in space and dazzles us."

This type of pollution affects living beings in many ways, and not just terrestrial animals, as various studies have shown.

For example, research in 2015 noted that marine protected areas were increasingly exposed to artificial light due to the proliferation of cruise ships, oil rigs, and coastal development.

Lighting that modifies the behavior of marine inhabitants, since many species, such as squid and zooplankton, are guided by patterns of natural light.

Regarding the specific situation in Spain, Bachiller considers that it is not exemplary: "The night map of the Iberian Peninsula shows how the lights of our cities stand out. The satellite images of our country show the largest area saturated with light by Spanish

and Madrid and Valencia are among the cities with the highest light pollution on the continent".

POT

However, he considers that "Spain is playing an important role for its protection. Thus,

from light pollution and is now an authentic reserve for the study of the sky. The Starlight Foundation created in Spain is carrying out an exemplary job certifying the quality of the areas with darker skies (both in Spain and abroad) and recommending their urgent protection".

And the good news is that, according to the astronomer, it is an easy problem to solve: "Light is one of the easiest forms of pollution to correct: it is

In Spain we have left some of the darkest corners of Europe Let us trust that the new Royal Decree that seeks to regulate outdoor lighting takes into account the numerous allegations that are being prepared by associations of astronomers and other groups sensitive to the immense value of our dark night sky ".

Bachiller recalls that "many children and young people who live in urban areas have not been able to see the Milky Way in their entire lives and, if it continues like this, they will soon have to travel to remote places to see it. Everyone (and not just the astronomers) should be entitled to enjoy the darkness of the night sky.

According to the criteria of The Trust Project

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