Our stars are disappearing from the night sky – here’s why
The Milky Way in a dark night sky with illuminating stars, part of the galaxy that contains our solar system, as seen from the sandy beach of Halkidiki, Greece
Stargazing is increasingly difficult in today’s world – and according to new research, it’s only getting worse.
The US astronomy research center NOIRLab has found that a child born today can see, for example, 250 stars in the sky at their own place. But by the time they turn 18, that number may have dropped to a hundred.
In fact, now about 30 percent of the world’s population can no longer see all the stars they should be able to. from NOIRLab a citizen science program named Earth at nightwhere crowdsourced results were posted online.
And we should be able to see several thousand stars on a clear but dark night, everywhere in the Milky Way, without telescopes, just through patient skygazing.
Where are the stars really going?
It is clear that the stars have not disappeared anywhere.
It all depends on that our own world of light – something we have previously measured via satellites by looking at Earth’s brightness at night – as this obscures our view of the night sky.
USA at night is a combination compiled from data collected by the Finnish nuclear power plant satellite in April and October 2012.
But these new Globe at Night observations show that our stars are disappearing from view faster than satellite measurements previously suggested.
Astronomers have called the phenomenon “sky glow,” where the night sky is illuminated by something other than natural elements such as stars and the moon.
Globe at Night suggests that sky brightness (sky glow) increased by 9.6% per year over the past decade, compared to 2% measured by satellites.
Astronomer Connie Walker warned that these observations highlight the “importance of redoubling our efforts” to reduce the “sky glow”.
The crowdsourced study, based on 50,000 observations from Europe and North America between 2011 and 2022, provides an estimate of the “unaided-eye-limited magnitude” – a measure of how bright something needs to be before it can be seen.
How serious is the sky glow?
The sky glow is unnatural and disrupts the natural cycle of day and night, which means it affects wildlife as many animals’ instincts are based on their reaction to daylight.
National Geographic has also highlighted that light pollution also affects humans, reducing melatonin production, triggering sleep disorders, fatigue, headaches, stress, anxiety and other health problems in humans.
And while the study focused on observations from Europe and North America, the increasing use of artificial light in other parts of the world means skyglows are likely to occur there too.
There are also concerns about what is happening in the night sky from our previous measurements.
“This shows that existing satellites are not enough to study how Earth’s night changes,” said study lead author Christopher Kyba of the German Geosciences Research Institute.