Thursday Feb 2, 2023
Thursday Feb 2, 2023

Twinkle, twinkle fading stars: Hiding in our brighter skies


Nepalnews
2023 Jan 24, 7:12, WASHINGTON
A view from the camping platform Cedar Hammock on the east side of the Okefenokee National Wildlife Refuge picks up light pollution from the Southeast of the refuge, Wednesday, March 30, 2022, in Folkston, Ga. (AP Photo)

Every year, the night sky grows brighter, and the stars look dimmer.

A new study that analyzes data from more than 50,000 amateur stargazers finds that artificial lighting is making the night sky about 10% brighter each year.

That’s a much faster rate of change than scientists had previously estimated looking at satellite data. The research, which includes data from 2011 to 2022, is published Thursday in the journal Science.

As cities expand and put up more lights, “skyglow” or “artificial twilight,” as the study authors call it, becomes more intense.

The 10% annual change “is a lot bigger than I expected — something you’ll notice clearly within a lifetime,” said Christopher Kyba, a study co-author and physicist at the German Research Centre for Geosciences in Potsdam.

Kyba and his colleagues gave this example: A child is born when 250 stars are visible on a clear night. By the time that child turns 18, only 100 stars are still visible.

The study data from amateur stargazers in the nonprofit Globe at Night project was collected in a similar fashion. Volunteers look for the constellation Orion – remember the three stars of his belt – and match what they see in the night sky to a series of charts showing an increasing number of surrounding stars.

Dave Cooke observes the Milky Way over a frozen fish sanctuary in central Ontario, north of Highway 36 in Kawartha Lakes, Ontario, Canada, early Sunday, March 21, 2021. (via AP)
Dave Cooke observes the Milky Way over a frozen fish sanctuary in central Ontario, north of Highway 36 in Kawartha Lakes, Ontario, Canada, early Sunday, March 21, 2021. (via AP)

Prior studies of artificial lighting, which used satellite images of the Earth at night, had estimated the annual increase in sky brightness to be about 2% a year.

But the satellites used aren’t able to detect light with wavelengths toward the blue end of the spectrum — including the light emitted by energy-efficient LED bulbs.

More than half of the new outdoor lights installed in the United States in the past decade have been LED lights, according to the researchers.

The satellites are also better at detecting light that scatters upward, like a spotlight, than light that scatters horizontally, like the glow of an illuminated billboard at night, said Kyba.

Skyglow disrupts human circadian rhythms, as well as other forms of life, said Georgetown biologist Emily Williams, who was not part of the study.

Part of what’s being lost is a universal human experience, said Falchi, the physicist at the University of Santiago de Compostela.

READ ALSO:

new study stargazers artificial lighting night sky 10% brighter each year science Geosciences
Nepal's First Online News Portal
Published by Nepalnews Pvt Ltd
Editor: Raju Silwal
Information Department Registration No. 1505 / 076-77

Contact

KMC-02, UttarDhoka,
Lazimpat, Nepal

Newsroom
+977–01–4445751 / 4445754

E-mail
[email protected] [email protected]

Terms of Use Disclaimer
© NepalNews. 2021 All rights reserved. | Nepal's First News Portal