People love to wish upon the first star seen at night -- but a third of the world's population are missing out.
A new study has shone a light on the issue of artificial brightness and it's found a lot of the world is missing out on the dark.
Instead, the intensity and amount of bright lights in populated areas fog out the Milky Way.
Researchers in Italy, Germany, Israel and the US worked together to create the new World Atlas of Artificial Sky Brightness, which was published in the Science Advances journal on Saturday.
An interactive map of light pollution has been released as part of the work.
(Falchi et al., Sci. Adv., Jakob Grothe/NPS contractor, Matthew Price/CIRES.)
By area, Canada and Australia are the least polluted, while Singapore, Italy and South Korea are the most.
And when it comes to wishing on a star, those in South Korea and Saudi Arabia are the mostly likely to miss out, their bright views having a dimmer effect.
World map of artificial sky brightness (Supplied)
In New Zealand, artificial light blocks eight in 10 people from seeing the stars.
And for nearly five percent of the population, light pollution is so bright people's eyes can't adapt properly to the dark.
Map of artificial sky brightness for New Zealand, Australia and Indonesia (Supplied)
US scientist Chris Elvidge works with NOAA's National Centers for Environmental Information in Colorado.
Eighty percent of people in the States can't see the stars from their homes, and he says it means there are "entire generations" of people who haven't seen the Milky Way.
"It's a big part of our connection to the cosmos -- and it's been lost."
Dark skies are important for more than just stargazing -- artificial lighting disturbs the day/night cycle for wildlife.
The Milky Way disappears in Berlin's light-dome (A. Jechow / IGB)
The research is an important map of the night environment as the world nears a widescale transition to LED technology, lead author Fabio Falchi from the Italian Light Pollution Science and Technology Institute says.
"Unless careful consideration is given to LED colour and lighting levels, this transition could unfortunately lead to a 2-3 fold increase in skyglow on clear nights," he says.
A similar atlas was published in 2001 and the researchers say the new report is a major advancement.
Data was gathered through the American Suomi NPP satellite, which carried a new instrument designed to accurately observe urban lights from space, and calibrated with nearly 21,000 "Sky Quality Meters" worldwide.
Around 20 percent of the calibration data was provided by citizen scientists, something study co-author Dr Christopher Kyba says was crucial to the success of the atlas.
"Without them we would not have had calibration data from countries outside of Europe and North America."
Newshub.
