All we need to find is the reason why are stars disappearing from the night sky. Well, its answer is “skyglow,” the stars in the sky are disappearing more quickly than in earlier decades.
What is Skyglow?
Skyglow, which occurs when artificial light sources are used excessively and inappropriately in densely populated urban areas worldwide, is the lightening of the night sky. For instance, streetlamps, floodlights, security illumination, lit structures, runway lights at airports, and so forth. While the average person may see hundreds of stars with their naked eye in a clear night sky, many stars and constellations are gradually disappearing.
Skyglow has long been recognized as a concern, but Globe at Night, an international research effort, contends that this issue is growing far more quickly than indicated by satellite measurements.
The night sky is becoming nearly 10% brighter annually thanks to artificial lighting, according to a recent study that examined data from more than 50,000 amateur astronomers.
That represents a significantly higher pace of change than what researchers had previously predicted using satellite data. The study, which uses data from 2011 to 2022, is released in the journal Science on Thursday.
“We are losing, year by year, the possibility to see the stars,” said Fabio Falchi, a physicist at the University of Santiago de Compostela, who was not involved in the study.
“If you can still see the dimmest stars, you are in a very dark place. But if you see only the brightest ones, you are in a very light-polluted place,” he said.
As cities expand and put up more lights, “skyglow” or “artificial twilight,” as the study authors call it, becomes more intense.
It “is a lot bigger than I imagined — something you’ll notice clearly within a lifetime,” said Christopher Kyba, a physicist at the German Research Centre for Geosciences in Potsdam and one of the study’s co-authors.
A kid is born when 250 stars are visible on a clear night, according to an example given by Kyba and his associates. Only 100 stars are still visible when that child reaches the age of 18 years.
“This is real pollution, affecting people and wildlife,” said Kyba, who said he hoped that policymakers would do more to curb light pollution. Some localities have set limits.
Similar methods were used to gather study data from amateur astronomers participating in the charity Globe at Night project. Volunteers search for the constellation Orion, keeping in mind the three stars that make up his belt, and compare what they see in the night sky to a succession of charts that display an expanding number of nearby stars.
Previous studies on artificial lighting that made use of nighttime satellite photographs of the Earth’s surface concluded that the brightness of the sky was increasing by around 2% annually.
However, the light emitted by energy-efficient LED bulbs as well as other light with wavelengths approaching the blue end of the spectrum cannot be detected by the satellites in use.
The researchers found that LED lights have been used in more than half of the recent outdoor lighting installations in the US.
According to Kyba, the satellites are also more effective at detecting light that spreads upward, like a spotlight, than light that spreads horizontally, like the glow of a billboard that has been lit at night.
According to Georgetown biologist Emily Williams, who was not involved in the study, skyglow interferes with both human circadian rhythms and those of other living things.
“Migratory songbirds normally use starlight to orient where they are in the sky at night,” she said. “And when sea turtle babies hatch, they use light to orient toward the ocean – light pollution is a huge deal for them.”
Part of what’s being lost is a universal human experience, said Falchi, the physicist at the University of Santiago de Compostela.
“The night sky has been, for all the generations before ours, a source of inspiration for art, science, and literature,” he said.
