Light Pollution Archives

January 10, 2025January 10, 2025 by Andy Tomaswick

A New Industrial Megaproject Threatens the View of the World’s Best Observatories

The dark skies above ESO’s Paranal Observatory, home to ESO’s Very Large Telescope (VLT), yield breathtaking views so clear and so full of stars that you could almost touch them. Standing atop a platform at VLT, ESO Photo Ambassador Petr Horálek reaches towards a standout object in the sky. You may assume this bright body, like many others in the sky, to be a star, but it is in fact a planet in our Solar System: the gas giant Jupiter. Closer to Earth, the four Unit Telescopes (UTs) that comprise the VLT can be seen in the background. Each UT features an 8.2-metre mirror and they operate synergistically to produce some of the sharpest views of the Universe. Accompanying the four UTs are four smaller, moveable Auxiliary Telescopes (ATs) which have 1.8-metre mirrors. The Chilean Atacama desert once again proves its value as the ideal location for ESO’s VLT. The remoteness of the observatory means that there is very little to no light pollution, which is vital for astronomy and also yields such breathtaking views.

Astronomers have been battling threats to their clear skies on all fronts lately. One of the most notable battles, which we have reported on repeatedly, is the one against Starlink and other mega-constellations of satellites, which, while they offer high-speed internet in the most far-flung places, also disrupt observations by sensitive telescopes due to their reflectivity and fast movement speed. They also pose a global problem, whereas a more down-to-earth issue is cropping up at one very special observatory. A vast industrial plant threatens the European Southern Observatory’s Paranal telescope planned only a few kilometers from the site.

January 8, 2025January 8, 2025 by Brian Koberlein

Astronomers are Losing the Night Sky (and Radio Sky) to Satellite Megaconstellations

How constellation satellites can create light pollution for radio telescopes. Credit: IAU CPS/NOIRLab/SKAO

When was the last time you looked up into the night sky and saw the Milky Way? If you happen to live in one of the truly remote areas of the world, your answer might be “last night.” If you live in one of the generally “rural” areas of your country, you might remember how you used to see the Milky Way regularly, but the rise of LEDs, particularly the blue/white ones, has gradually erased the Milky Way from your nights. For the large majority of humans on our small world, the answer is “never.”

September 19, 2024September 19, 2024 by Mark Thompson

Building a Worldwide Map of Light Pollution

As someone that has always lived in the UK countryside I am no stranger to the glory of a dark star-filled sky. Sadly 60% of the world’s population has already lost access to the night sky thanks to light pollution. Across Europe and the US that number climbs to nearer 80%. A team of researchers want to try and track the growth of light pollution and to that end have developed an inexpensive sensor made from “off-the-shelf” parts. Their hope is that people around the world will build and install these sensors to share their data enabling them to track the spread of light pollution. If you’ve got technical skills, this could be a fun project.

February 1, 2024February 1, 2024 by Evan Gough

Space Junk is Going to be a Problem for Vera Rubin

The Vera Rubin Observatory is poised to begin observations next year. It could detect 130 Near Earth Objects each night. Image Credit: Rubin Observatory/NSF/AURA/B. Quint

The Vera Rubin Observatory (VRO) is different than other large telescopes, and that difference makes it more vulnerable to space junk. Other telescopes, like the Giant Magellan Telescope and the European Extremely Large Telescope, focus on distant objects. But the VRO’s job is to repeatedly image the entire available night sky for ten years, spotting transients and variable objects.

All that space junk can look like transient events, impairing the VRO’s vision and polluting its results.

December 31, 2023December 31, 2023 by Carolyn Collins Petersen

How a Small Town in Japan Fiercely Defends its Dark Skies

The arch of the Milky Way seen over Bisei Town in Japan. It prides itself on its dark skies, but faces scattered light pollution from other nearby municipalities. Courtesy DarkSky.Org.

Light pollution ruins dark skies. It’s a scourge that ground-based observatories have to deal with in one form or another. Scientists used a small observatory in Japan to measure what changed when a nearby town improved its lighting practices. They also noted the challenges it still faces.

October 6, 2023October 6, 2023 by Evan Gough

One of the Brightest Stars in the Sky is Actually a Satellite

The bright streaks drawing an arc across the night sky are caused by the satellite BlueWalker 3. The prototype satellite is brighter than most stars. Image Credit: Ilse Plauchu-Frayn

Back in the 70s, kids used to look up at the summer sky and try to be the first one to shout, “Satellite!” That seems like a relic from the past now, alongside Polaroid cameras and astronauts on the Moon. These days, it’s rare to spend any amount of time looking at the sky without seeing a satellite, or several of them.

A new satellite is emphasizing that fact. It’s a prototype communications satellite with a roughly 700-square-foot antenna, and it’s brighter than most stars.

August 4, 2023August 4, 2023 by Andy Tomaswick

Light Pollution from Skyglow Changes Bird Behavior

In the astronomy community, we typically this of light pollution as an overall negative. Much research points out its negative effect on our sleep and even our observational equipment. It also significantly impacts wildlife; however, according to a new paper from some Belgian, Swiss, and German researchers, not all of that impact is negative.

July 7, 2023July 7, 2023 by Brian Koberlein

Astronomers Map out the Radio Waves Coming From Large Satellite Constellations

Illustration Starlink satellites over LOFAR. Credit: Daniëlle Futselaar

Satellite internet constellations such as Starlink have the potential to make connect nearly the entire world. Starlink already provides internet access to remote areas long excluded by the internet revolution, and other projects such as OneWeb and Project Kuiper are in the works. But there are side effects to creating a massive array of low-orbit satellites, and one of them is the potentially serious effect on astronomy.

June 29, 2023June 29, 2023 by Evan Gough

Light Pollution is Out of Control

The Earth at night. What will it look like 100 years from now? Image credit: NASA-NOAA

Concern over global light pollution is growing. Astronomers are noticing its growing effect on astronomical observations, just as predicted in prior decades. Our artificial light, much of which is not strictly necessary, is interfering with our science.

But there’s more than just scientific progress at stake. Can humanity afford to block out the opportunities for wonder, awe, and contemplation that the night sky provides?

January 20, 2023January 20, 2023 by Evan Gough

Light Pollution is Obscuring the Night Sky. RIP Stargazing

A startling analysis from Globe at Night — a citizen science program run by NSF’s NOIRLab — concludes that stars are disappearing from human sight at an astonishing rate. Image Credit: NOIRLab/NSF/AURA, P. Marenfeld

A citizen science initiative called Globe at Night has some sobering news for humanity. Our artificial light is drowning out the night sky for more and more people. And it’s happening more rapidly than thought.