PhD Position in Metrology for Skyglow Measurement and Monitoring (4 years – 100%)

The Swiss Federal Institute of Metrology METAS is the reference institute for measurements and measuring instruments in Switzerland. To ensure that a litre is always a litre (e.g. when filling up with petrol), METAS carries out calibrations, conformity assessments and consultations for industry, research and administration. Measurement accuracy creates trust, especially at the social and political level, and is essential in many areas: road traffic, electricity billing, time transmission, measurements in the environmental and health sectors, etc. At METAS, different fields of expertise come together and complement each other – and have done so since 1862. <br><br><b>Project & Position Overview:</b> The research project

A few bright buildings light up the entire night sky

When millions of people turn off their lights for Earth Hour each year, something remarkable happens in the night sky above cities. New research from Hong Kong published in Scientific Reports shows that just a small number of decorative buildings and advertising boards can dramatically brighten the entire urban night sky and when they go dark, the sky becomes up to 50% darker.

Natural experiments from Earth Hour reveal urban night sky being drastically lit up by few decorative buildings - Scientific Reports

Light pollution, a typically underrecognized environmental issue, has gained attention in recent years. While controlling light pollution requires sustained efforts, Earth Hour offers a unique natural experimental setting to assess temporary lights-out measures. Using photometric and spectroscopic sensors, we observed up to 50% night sky darkening during Earth Hour from 2011 to 2024 in Hong Kong, primarily as a result of a small but critical number of lights-out instances in central business districts, as evidenced by crowd-sourced photography records. Weekend lighting pattern in the city during Earth Hour remained unaffected. The emission reductions mostly occurred in the 445–500, 500–540, and 615–650 nm spectral ranges—corresponding to peak emissions from LED billboard screens— and in the 585–595 nm range, associated with metal halide floodlights used for facades and billboards. Our study identifies these sources as major contributors to urban light pollution. By combining multimodal observations, we offer a comprehensive assessment of light pollution sources and the potential benefits of sustainable lighting practices in urban environments. This research highlights the importance of targeted light pollution mitigation efforts and provides critical insights for policymakers to enhance urban sustainability and human well-being.

From ground to sky: reconciling light pollution measurements from above and below

Image credit: lightpollutionmap.info and Globe At Night 1513 words / 6-minute read

Tiny Moth Seen Navigating by The Stars in Scientific First

Every year, the bogong moth makes an epic journey across Australia.

Light pollution stimulates cyanobacterial growth and metabolic processes in lakes | IGB

New ESO analysis confirms severe damage from industrial complex planned near Paranal

An in-depth technical analysis by the European Southern Observatory (ESO) has evaluated the impact of the INNA megaproject on the facilities at the Paranal Observatory, Chile — and the results are alarming. The analysis reveals that INNA would increase light pollution above the Very Large Telescope (VLT) by at least 35% and by more than 50% above the south site of the Cherenkov Telescope Array Observatory (CTAO-South). INNA would also increase air turbulence in the area, further degrading conditions for astronomical observations, while vibrations from the project could seriously impair the functioning of some of the astronomical facilities, like the Extremely Large Telescope (ELT), at the Paranal Observatory.