Nothing steals away at the awe of the night sky more than light pollution. It is recognised by scientists all over the world as a threat not just to star gazing but also to nocturnal birds, insects, mammals and the ecosystems in which they live.
Light pollution also constitutes a huge waste of taxpayers’ money all over the world in funding of unnecessarily bright and badly-designed public and private exterior lighting schemes. It affects fields as diverse as ecology, astronomy, healthcare and land-use planning.
A new groundbreaking study was published last month in the journal Science Advances by researchers from Italy, Germany, the US and Israel. It aimed to quantify the effects of light pollution on a global scale using high-resolution satellite data as well as ground-based readings. Thousands of night sky brightness measurements were carried out to produce global colour-coded Earth maps that compare the levels of artificial brightness of the skies to natural levels.
It was found that over 80 per cent of the world’s population (including more than 99 per cent of the US and European populations) live under light-polluted skies. The Milky Way is not visible to more than a third of humanity, unless they travel to darker locations.
The most light polluted country is Singapore, followed by Kuwait, Qatar and the UAE. Malta is mentioned as having 89 per cent of its territory where the night skies are lit up to the extent that the Milky Way is hidden by light pollution.
In Western Europe there remain only a few small areas where the night sky is relatively unpolluted, including areas in Scotland, Sweden, Norway and some parts of Spain and Austria.
The study also highlights the effects of the transition from high-pressure sodium roadlighting to white LED lighting. White lighting increases light pollution by a factor of about 2.5 times. Artificial light from streetlamps and buildings creates ‘skyglow’ – the most visible effect of light pollution, the murky glow above our cities which obscures stars and constellations.
Exposure to artificial light at night has raised concerns about human health through a documented increase in risks of sleep disorders, diabetes, breast cancer and depression
Exposure to artificial light at night has also raised concerns about human health through a documented increase in risks of sleep disorders, diabetes, breast cancer and depression.
Light pollution is a global issue, but low-cost solutions already exist. Nobody is saying: “Let’s not have light at night”, and understandably, industrialised and developed countries as well as those with a high population density suffer most from light pollution.
There are easy solutions for lighting in a way which produces much less impact. There is no need to switch off any essential lighting. However, we should:
(a) only install fully shielded lights, that is, no light thrown into the sky or outside the areas intended to be lit;
(b) use the lowest recommended light levels for the task (anything more wastes energy and money);
(c) switch off or dim substantially lighting when not required, and
(d) not use high-colour temperature light sources (limit to a maximum of 3,000K).
Peeking through our light polluted skies in early August, one can manage to see all the bright planets in our solar system visible during the evening hours.
Soon after sunset one will be able to see Jupiter, with Mercury and Venus to its lower right-hand side as one faces west.
The thin crescent moon will be close by next Thursday and Friday. A flat, unobstructed western horizon will be necessary to catch these planets in the bright twilight.
As the skies get darker, a second grouping of planets is visible in the south/southwest, consisting of Mars and Saturn.
The annual Perseid meteor shower kicks off in the coming days, reaching its peak activity during the nights of August 12 and 13. The Perseids are best seen between 2 and 6am and there is speculation this year of increased activity, based on peaks over the past century.
The moon will be at a waxing gibbous phase, setting at around 1am, so there will be perfect natural darkness after that – except for any light pollution!
Alexei Pace is a member of the Astronomical Society of Malta.
Astronomical events during August
Tuesday: New moon
Thursday: Moon close to Venus and Mercury
Saturday: Moon close to Jupiter
Aug 10: Moon apogee: 404,300km
Aug 10: First quarter
Aug 12: Moon close to Saturn
Aug 12: Perseid meteor shower maximum
Aug 18: Full moon
Aug 22: Moon perigee: 367,000km
Aug 25: Last quarter
Aug 27: Venus close to Jupiter